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Vilela Junior, Wagner A., Antonio P. Coimbra, Gabriel A. Wainer, Joao Caetano Neto, Jose A. G. Cararo, Marcio R. C. Reis, Paulo V. Santos und Wesley P. Calixto. „Analysis and Adequacy Methodology for Voltage Violations in Distribution Power Grid“. Energies 14, Nr. 14 (20.07.2021): 4373. http://dx.doi.org/10.3390/en14144373.
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This paper proposes a computational process development capable of filling the electric power sector shortage regarding voltage non-conformities identification in electric distribution power grid accounting for loads dynamic behavior at medium and low voltages. Actual distribution power grid data are used, with georeferencing to signal voltage transgressions locations, generate a report with voltage transgression indices and financial reimbursement values provided by legislation. The methodology compares regulatory requirements and makes available in software some possible actions in an attempt to adjust voltage levels, avoiding inconvenience and penalties for energy utilities providers. The method involves a data extractor construction for electricity provider company’s databases, computer simulations and comparison of obtained results with values established in electricity quality control standards. Thus, finding non-conformity locations and determining network adjustments to correct tension indexes in permanent regulation. The proposal features a reduction in electricity utilities operating costs, increasing efficiency in operation and energy quality available to consumers.
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Ma, Xing He, Bing Yao Yan und Yong Sheng Wang. „Medium Voltage Distribution Network Voltage Grade Sequence Comprehensive Evaluation Based on Gray/Ahp“. Applied Mechanics and Materials 273 (Januar 2013): 332–37. http://dx.doi.org/10.4028/www.scientific.net/amm.273.332.
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Analyze our country medium voltage distribution network voltage grade sequence current situation, consider technological factors, economic factors and equipment factors, establish voltage grade sequence analysis model, through the grey /ahp, evaluation analysis model. Finally, Given the typical regional network model, the grey/ahp analyses. Example showes, the method is helpful for regional power grid voltage grade the qualitative and quantitative evaluation.
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Save, Nishant, Marjan Popov, Arjen Jongepier und Gert Rietveld. „PMU-based power system analysis of a medium-voltage distribution grid“. CIRED - Open Access Proceedings Journal 2017, Nr. 1 (01.10.2017): 1927–30. http://dx.doi.org/10.1049/oap-cired.2017.1035.
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Diamenu, Godwin. „Statistical Analysis of Electric Power Distribution Grid Outages“. European Journal of Engineering and Technology Research 6, Nr. 3 (12.04.2021): 27–33. http://dx.doi.org/10.24018/ejers.2021.6.3.2406.
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Power systems in general supply consumers with electrical energy as economically and reliably as possible. Reliable electric power systems serve customer loads without interruptions in supply voltage. Electric power generation facilities must produce enough power to meet customer demand. Electrical energy produced and delivered to customers through generation, transmission and distribution systems, constitutes one of the largest consumers markets the world over. The benefits of electric power systems are integrated into the much faster modern life in such extent that it is impossible to imagine the society without the electrical energy. The rapid growth of electric power distribution grids over the past few decades has resulted in a large increment in the number of grid lines in operation and their total length. These grid lines are exposed to faults as a result of lightning, short circuits, faulty equipment, mis-operation, human errors, overload, and aging among others. A fault implies any abnormal condition which causes a reduction in the basic insulation strength between phase conductors or phase conductors and earth, or any earthed screens surrounding the conductors. In this paper, different types of faults that affected the electric power distribution grid of selected operational districts of Electricity Company of Ghana (ECG) in the Western region of Ghana was analyzed and the results presented. Outages due to bad weather and load shedding contributed significantly to the unplanned outages that occurred in the medium voltage (MV) distribution grid. Blown fuse and loose contact faults were the major contributor to unplanned outages in the low voltage (LV) electric power distribution grid.
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Jia, Yu Wei, Wang Ding und Jia Dong Huang. „Medium Voltage Distribution Network Planning of City Based on Reliability“. Advanced Materials Research 655-657 (Januar 2013): 2401–4. http://dx.doi.org/10.4028/www.scientific.net/amr.655-657.2401.
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Power network planning is an important foundation of the development of the grid, its planning level and quality directly affects the security, reliability, and economic level of the power grid. This article will carry on the analysis according to the reliable condition to the city distribution network, mainly includes the structure of the urban network wiring, the form of the host wiring and medium voltage distribution network wiring and so on.
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Schultis, Daniel-Leon, und Albana Ilo. „Increasing the Utilization of Existing Infrastructures by Using the Newly Introduced Boundary Voltage Limits“. Energies 14, Nr. 16 (19.08.2021): 5106. http://dx.doi.org/10.3390/en14165106.
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The increasing share of distributed generation aggravates voltage limit compliance at customers’ delivery points. Currently, grid operators validate compliance with the voltage limits specified in Grid Codes by conducting load flow simulations at the medium voltage level, considering the connected low voltage grids as ‘loads’ to reduce the modeling effort. This approach does not support the accurate validation of limit compliance, as the voltage drops at the low voltage level are unknown. Nevertheless, to guarantee acceptable voltages even under worst-case conditions, safety margins are involved that impair the utilization of the electricity infrastructure. This study conducts load flows simulations in a test distribution grid, revealing the variable character of the voltage limits at different system boundaries. The conventional load model is extended by new parameters—the boundary voltage limits—to enable the consideration of variable voltage limits in load flow analysis of LINK-based smart grids. The standardized structure of the LINK-architecture allows for the systematic and accurate validation of voltage limit compliance by reducing the required modeling data to the technically necessary minimum. Use cases are specified that allows smart grids to increase the utilization of the electricity infrastructure by day-ahead scheduling and short-term adaptation of boundary voltage limits.
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Montoya, Oscar Danilo, Walter Gil-González, Andrés Arias-Londoño, Arul Rajagopalan und Jesus C. Hernández. „Voltage Stability Analysis in Medium-Voltage Distribution Networks Using a Second-Order Cone Approximation“. Energies 13, Nr. 21 (02.11.2020): 5717. http://dx.doi.org/10.3390/en13215717.
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This paper addresses the voltage stability margin calculation in medium-voltage distribution networks in the context of exact mathematical modeling. This margin calculation is performed with a second-order cone (SOCP) reformulation of the classical nonlinear non-convex optimal power flow problems. The main idea around the SOCP approximation is to guarantee the global optimal solution via convex optimization, considering as the objective function the λ-coefficient associated with the maximum possible increment of the load consumption at all the nodes. Different simulation cases are considered in one test feeder, described as follows: (i) the distribution network without penetration of distributed generation; (ii) the distribution network with penetration of distributed generation; and (iii) the distribution grid with capacitive compensation. Numerical results in the test system demonstrated the effectiveness of the proposed SOCP approximation to determine the λ-coefficient. In addition, the proposed approximation is compared with nonlinear tools available in the literature. All the simulations are carried out in the MATLAB software with the CVX package and the Gurobi solver.
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Zhang, Meng, Feng Zhan Zhao, Xiao Li Meng, Xiao Hui Song, Ren Gang Yang, Ye Sheng und Zhi Jun Ye. „Establishment of Smart Distribution Grid Evaluation System“. Applied Mechanics and Materials 719-720 (Januar 2015): 443–47. http://dx.doi.org/10.4028/www.scientific.net/amm.719-720.443.
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This paper analyzes the core values of the smart grid that is the need of significant stakeholders, the reliable and efficient electricity supply for users and running economy for power grid enterprises. Using fishbone analysis gets the main elements, which are the quality and reliability of power supply, grid structure, equipments situation, intelligence level and operation level. Due to the complexity of the evaluation system,the entire system divided into three layer levels,the target layer, the element layer and the index layer. The structure and operation of low voltage distribution grid and medium-high voltage distribution are significantly different,they separate into two systems to evaluate,it can get the evaluation index system. Compared with the traditional distribution grid evaluation system, this system is more comprehensive and systematic for evaluation the development level of the smart distribution grid,it is practically valuable for evaluation work.
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D.Srinivasa Rao & Dr. Anupama A. Deshpande. „DAB Based DC-DC High Frequency Link PET for Interconnecting MVDC-LVDC Grids“. International Journal for Modern Trends in Science and Technology 7, Nr. 05 (27.05.2021): 165–71. http://dx.doi.org/10.46501/ijmtst0705028.
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This paper proposes dual active bridge (DAB) based high frequency power electronic transformer (PET) for interconnecting medium voltage dc (MVDC) and low voltage dc (LVDC) grids for dc power distribution. The above proposed concept works on dual active phase shift principle and square wave HF modulation technique for bidirectional power transfer. Compared to the traditional dc transformer scheme, The proposed power electronic transformer (PET) can disconnect from LVDC distribution grid effectively as a dc breaker when a short circuit fault occurs in the distribution grid. The isolated DC-DC PET topology with a wide range of voltage conversion ratio is useful for High Voltage DC tapping. The DAB based on switched capacitor is connected to the medium voltage DC side and acts as an inverter. The proposed topology has the ability to transfer higher power, and lower circulating power, lower high frequency link voltage, and RMS current and peak values with the same transmission power in the MVDC side. This paper analyzes the topology, voltage and power characterization, control strategy in detail. Increase in the intermediate AC frequency will reduce the size of the transformer and other passive elements significantly in the circuit. The theoretical analysis is supported by MATLAB simulation.
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Camargo, Luis Ramirez, Jane Wuth, Markus Biberacher und Wolfgang Dorner. „A spatially explicit assessment of middle and low voltage grid requirements in Bavaria until 2050“. GeoScape 13, Nr. 2 (01.12.2019): 88–97. http://dx.doi.org/10.2478/geosc-2019-0008.
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Abstract The energy transition towards high shares of renewables and the continued urbanization process have a direct and strong impact on the shape and characteristics of the electricity transmission and distribution systems. At the continental and national scale, improved high voltage grids should allow the transmission and balance of electricity from hot-spots of variable renewable energy generation installations to demand centres. At the regional and municipal scale, the medium and low voltage grids should be capable of bringing sufficient electricity to users and allow the integration of distributed renewable generation installations. While data on the transmission systems is widely available, spatial and attribute data of the medium and mainly the low voltage grids are scarce. Additionally, while there are plenty of studies on the requirements of the grid to allow the energy transition, there is very little information on the necessary transformation of the grid due to changes generated by the expected urbanization process. This study relies on a data set that estimates the topology of the medium and low voltage grids of Bavaria (Germany) as well as data from the LUISA territorial modelling platform of the European Commission to calculate key figures of grid requirements depending on population and land use for the current case and the decades to come. Typologies of grid requirements are proposed based on a statistical analysis of population and land use data of each square kilometre of the federal state. These typologies are extrapolated to changes in the structure of settlements that are expected in the years 2030 and 2050. Results are presented using maps with expected absolute values of grid requirements and their temporal changes for each square kilometre of the project area. Grid requirements are expected to increase in cities and to be reduced in most of the rural areas. The largest changes are expected to take place in the suburbs of the major cities. Highlights for public administration, management and planning: • Medium and low voltage grid shapes and lengths are estimated for the entire federal state of Bavaria, Germany. • On average, distribution grid length requirements per person are between 13 and 16 times larger in rural regions than in city centres. • While city centres and suburbs expect an increase in grid requirements, the total grid length of Bavaria is expected to decrease in the near future. • Suburbs of large cities are not only expected to change steadily but also to show the largest changes in grid length requirements until 2050.
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Lazaropoulos, Athanasios G. „Broadband over Power Lines Systems Convergence: Multiple-Input Multiple-Output Communications Analysis of Overhead and Underground Low-Voltage and Medium-Voltage BPL Networks“. ISRN Power Engineering 2013 (15.09.2013): 1–30. http://dx.doi.org/10.1155/2013/517940.
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This review paper reveals the broadband potential of overhead and underground low-voltage (LV) and medium-voltage (MV) broadband over power lines (BPL) networks associated with multiple-input multiple-output (MIMO) technology. The contribution of this review paper is fourfold. First, the unified value decomposition (UVD) modal analysis is introduced. UVD modal analysis is a new technique that unifies eigenvalue decomposition (EVD) and singular value decomposition (SVD) modal analyses achieving the common handling of traditional SISO/BPL and upcoming MIMO/BPL systems. The validity of UVD modal analysis is examined by comparing its simulation results with those of other exact analytical models. Second, based on the proposed UVD modal analysis, the MIMO channels of overhead and underground LV and MV BPL networks (distribution BPL networks) are investigated with regard to their inherent characteristics. Towards that direction, an extended collection of well-validated metrics from the communications literature, such as channel attenuation, average channel gain (ACG), root-mean-square delay spread (RMS-DS), coherence bandwidth (CB), cumulative capacity, capacity complementary cumulative distribution function (CCDF), and capacity gain (GC), is first applied in overhead and underground MIMO/LV and MIMO/MV BPL channels and systems. It is found that the results of the aforementioned metrics portfolio depend drastically on the frequency, the power grid type (either overhead or underground, either LV or MV), the MIMO scheme configuration properties, the MTL configuration, the physical properties of the cables used, the end-to-end distance, and the number, the electrical length, and the terminations of the branches encountered along the end-to-end BPL signal propagation. Third, three interesting findings concerning the statistical properties of MIMO channels of distribution BPL networks are demonstrated, namely, (i) the ACG, RMS-DS, and cumulative capacity lognormal distributions; (ii) the correlation between RMS-DS and ACG; and (iii) the correlation between RMS-DS and CB. By fitting the numerical results, unified regression distributions appropriate for MIMO/BPL channels and systems are proposed. These three fundamental properties can play significant role in the evaluation of recently proposed statistical channel models for various BPL systems. Fourth, the potential of transformation of overhead and underground LV/BPL and MV/BPL distribution grids to an alternative solution to fiber-to-the-building (FTTB) technology is first revealed. By examining the capacity characteristics of various MIMO scheme configurations and by comparing these capacity results against SISO ones, a new promising urban backbone network seems to be born in a smart grid (SG) environment.
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Schultis, Daniel-Leon, und Albana Ilo. „Behaviour of Distribution Grids with the Highest PV Share Using the Volt/Var Control Chain Strategy“. Energies 12, Nr. 20 (12.10.2019): 3865. http://dx.doi.org/10.3390/en12203865.
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The large-scale integration of rooftop PVs stalls due to the voltage limit violations they provoke, the uncontrolled reactive power flow in the superordinate grids and the information and communications technology (ICT) related challenges that arise in solving the voltage limit violation problem. This paper attempts to solve these issues using the LINK-based holistic architecture, which takes into account the behaviour of the entire power system, including customer plants. It focuses on the analysis of the behaviour of distribution grids with the highest PV share, leading to the determination of the structure of the Volt/var control chain. The voltage limit violations in low voltage grid and the ICT challenge are solved by using concentrated reactive devices at the end of low voltage feeders. Q-Autarkic customer plants relieve grids from the load-related reactive power. The optimal arrangement of the compensation devices is determined by a series of simulations. They are conducted in a common model of medium and low voltage grids. Results show that the best performance is achieved by placing compensation devices at the secondary side of the supplying transformer. The Volt/var control chain consists of two Volt/var secondary controls; one at medium voltage level (which also controls the TSO-DSO reactive power exchange), the other at the customer plant level.
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Yao, Sen Jing, Zheng Guo Zhu, Hua Ying Zhang, Jun Wei Cao und Guang Yi Zhang. „The Design of Filter Parameters of Dynamic Voltage Restorer in Medium Voltage Network“. Applied Mechanics and Materials 654 (Oktober 2014): 133–41. http://dx.doi.org/10.4028/www.scientific.net/amm.654.133.
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Dynamic Voltage Compensator (DVR) is able to handle the dynamic power quality problems in distribution network, such as voltage sags and voltage unbalance, and the parameters of the output filter will have important affect on the compensation results. In this paper, the parameter design method of the output filter of a cascaded H-bridge based DVR applied in medium-voltage distribution grid is studied. Through the analysis of the case when filter inductor current has the maximum value, the theoretical expression of the relationship between the low limit of the value of filter inductor and the capability of voltage compensation and power factor is derived. Meanwhile, the method of selecting the filter capacitor value is obtained. The realization of the proposed method are given by taking an engineering project as an example, the correctness and validity of the design method of filter parameters proposed in this paper are verified by simulation.
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Kotsalos, Konstantinos. „Decentralized Voltage Regulation in radial Medium Voltage Networks with high presence of Distributed Generation“. U.Porto Journal of Engineering 3, Nr. 1 (26.03.2018): 26–38. http://dx.doi.org/10.24840/2183-6493_003.001_0003.
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The continuous growth of distributed generation along the medium voltage distribution networks (MVDN) induces multifaceted technical challenges that have to be addressed by alternative control architecture schemes beyond the centralized strategies and the fit and forget doctrine. The active participation of DG essentially drives the network to pave towards the Smart Grid concept. This paper entails a decentralized control strategy which is based on a sensitivity analysis to stipulate the proper dispatch set-points for the DGs; hence, all nodal voltages are in permissible bounds. An overview of sensitivity approaches is presented and discussed for their adequacy to be used in MVDN. The proposed method is simulated on a 13- Node Test Feeder IEEE benchmark, while its consistency is compared with a centralized scheme.
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Artale, Giovanni, Giuseppe Caravello, Antonio Cataliotti, Valentina Cosentino, Dario Di Cara, Salvatore Guaiana, Ninh Nguyen Quang, Marco Palmeri, Nicola Panzavecchia und Giovanni Tinè. „A Virtual Tool for Load Flow Analysis in a Micro-Grid“. Energies 13, Nr. 12 (18.06.2020): 3173. http://dx.doi.org/10.3390/en13123173.
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This paper proposes a virtual tool for load flow analysis in energy distribution systems of micro-grids. The solution is based on a low-cost measurement architecture, which entails low-voltage power measurements in each secondary substation and a voltage measurement at the beginning of the medium voltage (MV) feeder. The proposed virtual tool periodically queries these instruments to acquire the measurements. Then, it implements a backward–forward load flow algorithm, to evaluate the power flow in each branch and the voltage at each node. The virtual tool performances are validated using power measurements acquired at the beginning of each MV feeder. The uncertainties on each calculated quantity are also evaluated starting from the uncertainties due to the used measurement instruments. Moreover, the influence of the line parameter uncertainties on the evaluated quantities is also considered. The validated tool is useful for the online analysis of power flows and also for planning purposes, as it allows verifying the influence of future distributed generator power injection. In fact, the tool is able to off-line perform the load flow calculation in differently distributed generation scenarios. The micro-grid of Favignana Island was used as a case study to test the developed virtual tool.
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Grzanic, Flammini und Prettico. „Distribution Network Model Platform: A First Case Study“. Energies 12, Nr. 21 (25.10.2019): 4079. http://dx.doi.org/10.3390/en12214079.
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Decarbonisation policies have recently seen an uncontrolled increase in local electricity production from renewable energy sources (RES) at distribution level. As a consequence, bidirectional power flows might cause high voltage/ medium voltage (HV/MV) transformers to overload. Additionally, not-well-planned installation of electric vehicle (EV) charging stations could provoke voltage deviations and cables overloading during peak times. To ensure secure and reliable distribution network operations, technology integration requires careful analysis which is based on realistic distribution grid models (DGM). Currently, however, only not geo-referenced synthetic grids are available inliterature. This fact unfortunately represents a big limitation. In order to overcome this knowledge gap, we developed a distribution network model (DiNeMo) web-platform aiming at reproducing the DGM of a given area of interest. DiNeMo is based on metrics and indicators collected from 99 unbundled distribution system operators (DSOs) in Europe. In this work we firstly perform a validation exercise on two DGMs of the city of Varaždin in Croatia. To this aim, a set of indicators from the DGMs and from the real networks are compared. The DGMs are later used for a power flow analysis which focuses on voltage fluctuations, line losses, and lines loading considering different levels of EV charging stations penetration.
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Hindarianto, Jepi Yuli. „Analysis Of Power Quality Effect On The Life Time Transformer“. ACMIT Proceedings 5, Nr. 1 (19.03.2019): 57–64. http://dx.doi.org/10.33555/acmit.v5i1.75.
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In the industry that runs today, of course, electricity cannot be separated from the electricity used for all production processes. In Indonesia, currently PT. PLN (Persero) (PLN) is the only one of electrical energy provider for the medium and larger scale of industry. The electricity power for industry is usually supplied by 20 kV distribution grid. Meanwhile, industrial utilities, equipment and machinery mostly require lower voltage. Therefore, it is necessary to step down the voltage of the PLN distribution grid from 20 kV to 2 kV, 1 kV, 400 Volt or lower by using step down transformer. Step down transformer has very important role in any industrial facility. Failure and under performance in the maintenance and operation of step down transformer will cause significant effect to the continuation of industrial facility. There are several things that can affect the lifetime of the transformer, one of them is the power quality of the supplied electricity from the grid. The power quality in the form of Total Harmonic Distortion Voltage (THDV), Total Harmonic Distortion Current (THDI), voltage sag, flicker, current, and power must be maintained in required limit or standard range so that it keeps the step down transformer in the best performance and also longer lifetime. In order to know the performance and lifetime of the transformer, there are two important tests that need to carry out periodically which are Dissolved Gas Analysis (DGA) and Break Down Voltage (BDV) test. These tests examine the dissolved gas content and dielectric strength in the transformer oil. The work in this thesis is to carry out a study of power quality effect on a transformer lifetime. The supplied power quality of the PLN grid in the outgoing of step down transformer was measured by using HIOKI PW319 power analyser. Experiment and analysis in this thesis concluded that there is a strong correlation between the supplied power quality of PLN grid and the performance and lifetime of the examined transformers. Poor power quality causes the running lifetime and the performance of the examined transformers decreases.
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Gloe, Arne, Clemens Jauch und Thomas Räther. „Grid Support with Wind Turbines: The Case of the 2019 Blackout in Flensburg“. Energies 14, Nr. 6 (18.03.2021): 1697. http://dx.doi.org/10.3390/en14061697.
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The work presented in this paper aims to show how modern wind turbines can help to control the frequency in a small grid which suffers from large power imbalances. It is shown for an exemplary situation, which occurred in Flensburg’s distribution grid in 2019: a major blackout, which occurred after almost two hours in islanding operation, affecting almost the entire distribution grid, which supplies approximately 55,000 households and businesses. For the analysis, a wind turbine model and a grid support controller developed at the Wind Energy Technology Institute are combined with real measurements from the day of the blackout to generate a fictional yet realistic case study for such an islanding situation. For this case study, it is assumed that wind turbines with grid support functionalities are connected to the medium voltage distribution grid of the city. It is shown to what extent wind turbines can help to operate the grid by providing grid frequency support in two ways: By supplying synthetic inertia only, where the wind turbines can help to limit the rate of change of frequency in the islanded grid directly after losing the connection to the central European grid. In combination with the primary frequency control capabilities of the wind turbines (WTs), the disconnection of one gen set in the local power station might have been avoided. Furthermore, wind turbines with primary frequency control capabilities could have restored the grid frequency to 50 Hz shortly after the islanding situation even if the aforementioned gen-set was lost. This would have allowed connecting a backup medium voltage line to the central European grid and thereby avoiding the blackout.
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Saad, N. Md, M. Z. Sujod, Lee Hui Ming, M. F. Abas, M. S. Jadin, M. R. Ishak und N. R. H. Abdullah. „Impacts of Photovoltaic Distributed Generation Location and Size on Distribution Power System Network“. International Journal of Power Electronics and Drive Systems (IJPEDS) 9, Nr. 2 (01.06.2018): 905. http://dx.doi.org/10.11591/ijpeds.v9.i2.pp905-913.
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As the rapid development of photovoltaic (PV) technology in recent years with the growth of electricity demand, integration of photovoltaic distributed generation (PVDG) to the distribution system is emerging to fulfil the demand. There are benefits and drawbacks to the distribution system due to the penetration of PVDG. This paper discussed and investigated the impacts of PVDG location and size on distribution power systems. The medium voltage distribution network is connected to the grid with the load being supplied by PVDG. Load flow and short circuit calculation are analyzed by using DigSILENT Power Factory Software. Comparisons have been made between the typical distribution system and the distribution system with the penetration of PVDG. Impacts in which PVDG location and size integrates with distribution system are investigated with the results given from the load flow and short circuit analysis. The results indicate positive impacts on the system interconnected with PVDG such as improving voltage profile, reducing power losses, releasing transmission and distribution grid capacity. It also shows that optimal locations and sizes of DGs are needed to minimize the system’s power losses. On the other hand, it shows that PVDG interconnection to the system can cause reverse power flow at improper DG size and location and increases short circuit level.
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Potenciano Menci, Sergio, Julien Le Baut, Javier Matanza Domingo, Gregorio López López, Rafael Cossent Arín und Manuel Pio Silva. „A Novel Methodology for the Scalability Analysis of ICT Systems for Smart Grids Based on SGAM: The InteGrid Project Approach“. Energies 13, Nr. 15 (24.07.2020): 3818. http://dx.doi.org/10.3390/en13153818.
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Information and Communication Technology (ICT) infrastructures are at the heart of emerging Smart Grid scenarios with high penetration of Distributed Energy Resources (DER). The scalability of such ICT infrastructures is a key factor for the large scale deployment of the aforementioned Smart Grid solutions, which could not be ensured by small-scale pilot demonstrations. This paper presents a novel methodology that has been developed in the scope of the H2020 project InteGrid, which enables the scalability analysis of ICT infrastructures for Smart Grids. It is based on the Smart Grid Architecture Model (SGAM) framework, which enables a standardized and replicable approach. This approach consists of two consecutive steps: a qualitative analysis that aims at identifying potential bottlenecks in an ICT infrastructure; and a quantitative analysis of the identified critical links under stress conditions by means of simulations with the aim of evaluating their operational limits. In this work the proposed methodology is applied to a cluster of solutions demonstrated in the InteGrid Slovenian pilot. This pilot consists of a Large Customer Commercial Virtual Power Plant (VPP) that provides flexibility in medium voltage for tertiary reserve and a Traffic Light System (TLS) to validate such flexibility offers. This approach creates an indirect Transmission System Operator (TSO)—Distribution System Operator (DSO) coordination scheme.
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Kim, Juyong, Hongjoo Kim, Jintae Cho, Youngpyo Cho, Yoonsung Cho und Sukcheol Kim. „Demonstration Study of Voltage Control of DC Grid Using Energy Management System Based DC Applications“. Energies 13, Nr. 17 (02.09.2020): 4551. http://dx.doi.org/10.3390/en13174551.
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This paper is about the development of the real-time direct current (DC) network analysis applications for the operation of DC power systems. The applications are located in the central energy management system (EMS) and provide the operator with the optimal solution for operation in real time. Developed DC applications are not limited by voltage level. Applications can be used at all DC voltage levels such as low voltage, medium voltage and high voltage. A program configuration and sequence for analyzing the DC distribution system are suggested. Algorithms of each program are presented and the differences when compared with the processes of the applications of the existing alternating current (AC) systems are analyzed. The DC grid demonstration site at the Korea Electric Power Corporation (KEPCO) power testing center is introduced. The details of EMS and applications installation are described. The developed DC applications were installed in the EMS of the demonstration site and verification tests have been carried out. The configuration of the test scenario for testing the voltage control of the DC network is described. The voltage control result is analyzed and the measured data and the results of the applications are verified for compatibility by comparing them with the results of an off-line simulation tool. Finally, the future direction of the development of technology for the operation of the DC grid is introduced.
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Montoya, Oscar Danilo, Federico Martin Serra und Cristian Hernan De Angelo. „On the Efficiency in Electrical Networks with AC and DC Operation Technologies: A Comparative Study at the Distribution Stage“. Electronics 9, Nr. 9 (20.08.2020): 1352. http://dx.doi.org/10.3390/electronics9091352.
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This research deals with the efficiency comparison between AC and DC distribution networks that can provide electricity to rural and urban areas from the point of view of grid energy losses and greenhouse gas emissions impact. Configurations for medium- and low-voltage networks are analyzed via optimal power flow analysis by adding voltage regulation and devices capabilities sources in the mathematical formulation. Renewable energy resources such as wind and photovoltaic are considered using typical daily generation curves. Batteries are formulated with a linear representation taking into account operative bounds suggested by manufacturers. Numerical results in two electrical networks with 0.24 kV and 12.66 kV (with radial and meshed configurations) are performed with constant power loads at all the nodes. These simulations confirm that power distribution with DC technology is more efficient regarding energy losses, voltage profiles and greenhouse emissions than its AC counterpart. All the numerical results are tested in the General Algebraic Modeling System widely known as GAMS.
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Siodla, Krzysztof, Aleksandra Rakowska und Slawomir Noske. „The Proposal of a New Tool for Condition Assessment of Medium Voltage Power Cable Lines“. Energies 14, Nr. 14 (08.07.2021): 4116. http://dx.doi.org/10.3390/en14144116.
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A medium voltage (MV) cable network is a substantial component of the distribution network. Present management of this grid segment is mainly based on the failure rate analysis, i.e., a rise in the number and kind of faults on the actual line means that its technical condition is getting worse. The efficiency of the power system is low and additional costs of repair works, supply interruption, difficulties in the investment planning and operation and maintenance works are necessary. The aim of the R&D works done in the realised project is to implement the management of the MV cable network based on the estimated condition of the individual cable line, obtained from diagnostic measurements. The diagnostic investigations of the cable lines are the reference. Many years of research work have led to the development of the Health Index based on diagnostic, technical and service data.
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LIU, Changyi, Rong ZHU und Yang WANG. „Economic Assessment and Policy Analysis on Wind Energy Development in China“. Chinese Journal of Urban and Environmental Studies 05, Nr. 04 (Dezember 2017): 1750026. http://dx.doi.org/10.1142/s2345748117500269.
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Considering rapid development and emerging new challenges of China's wind energy development, this paper summarizes and analyzes five critical problems. First, according to an economic potential assessment, if the feed-in tariff is set 0.60 Yuan/kWh, the economic potential of wind electricity of China will reach 6.63[Formula: see text]PWh, it could meet as much as 2/3 of total power demand by 2030, thus the targeted wind power proportion in future high renewable energy penetration can be achieved. Second, wind energy is abundant but little consumed in Northwest, Northeast and North China while it is insufficient in South and East of China, where grid-connection condition is well. Due to this reverse distribution pattern of wind power endowment and consumption in China, grid-connection transmission must be strengthened in the future, particularly the West–East and North–South power transmission projects must be pushed forward. Third, to address the issue of increasing wind energy curtailment in Northeast, Northwest and North China, stimulating local consumption of wind power by multiple ways is a possible solution in the short term, however, in the medium and long run, it is necessary to accelerate the construction of Ultra-High Voltage power grid in order to expand power transmission to other provinces and regions. Fourth, a new electricity market mechanism should be established as the fundamental measure of promoting new energy development, while green certificate trading market and carbon trading market will form the basis for such market mechanism in the long run. Fifth, though wind power development can bring multiple benefits to economy, employment, and environment, large-scale wind power development will, to some extent, affect local and regional climate. As global warming continues, the wind power resource distribution of China and the world may experience significant changes.
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Deilami, Sara, und S. M. Muyeen. „An Insight into Practical Solutions for Electric Vehicle Charging in Smart Grid“. Energies 13, Nr. 7 (26.03.2020): 1545. http://dx.doi.org/10.3390/en13071545.
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The electrification of transportation has been developed to support energy efficiency and CO2 reduction. As a result, electric vehicles (EVs) have become more popular in the current transport system to create more efficient energy. In recent years, this increase in EVs as well as renewable energy resources (RERs) has led to a major issue for power system networks. This paper studies electrical vehicles (EVs) and their applications in the smart grid and provides practical solutions for EV charging strategies in a smart power system to overcome the issues associated with large-scale EV penetrations. The research first reviews the EV battery infrastructure and charging strategies and introduces the main impacts of uncontrolled charging on the power grid. Then, it provides a practical overview of the existing and future solutions to manage the large-scale integration of EVs into the network. The simulation results for two controlled strategies of maximum sensitivity selection (MSS) and genetic algorithm (GA) optimization are presented and reviewed. A comparative analysis was performed to prove the application and validity of the solution approaches. This also helps researchers with the application of the optimization approaches on EV charging strategies. These two algorithms were implemented on a modified IEEE 23 kV medium voltage distribution system with switched shunt capacitors (SSCs) and a low voltage residential network, including EVs and nonlinear EV battery chargers.
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Lazaropoulos, Athanasios G. „Towards Modal Integration of Overhead and Underground Low-Voltage and Medium-Voltage Power Line Communication Channels in the Smart Grid Landscape: Model Expansion, Broadband Signal Transmission Characteristics, and Statistical Performance Metrics (Invited Paper)“. ISRN Signal Processing 2012 (16.10.2012): 1–17. http://dx.doi.org/10.5402/2012/121628.
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The established statistical analysis, already used to treat overhead transmission power grid networks, is now implemented to examine the factors influencing modal transmission characteristics and modal statistical performance metrics of overhead and underground low-voltage/broadband over power lines (LV/BPL) and medium-voltage/broadband over power lines (MV/BPL) channels associated with power distribution in smart grid (SG) networks. The novelty of this paper is threefold. First, a refined multidimensional chain scattering matrix (TM2) method suitable for overhead and underground LV/BPL and MV/BPL modal channels is evaluated against other relative theoretical and experimental proven models. Second, applying TM2 method, the end-to-end modal channel attenuation of various LV/BPL and MV/BPL multiconductor transmission line (MTL) configurations is determined. The LV/BPL and MV/BPL transmission channels are investigated with regard to their spectral behavior and their end-to-end modal channel attenuation. It is found that the above features depend drastically on the frequency, the type of power grid, the mode considered, the MTL configuration, the physical properties of the cables used, the end-to-end distance, and the number, the electrical length, and the terminations of the branches encountered along the end-to-end BPL signal propagation. Third, the statistical properties of various overhead and underground LV/BPL and MV/BPL modal channels are investigated revealing the correlation between end-to-end modal channel attenuation and modal root-mean-square delay spread (RMS-DS). Already verified in the case of overhead high-voltage (HV) BPL systems, this fundamental property of several wireline systems is also modally validated against relevant sets of field measurements, numerical results, and recently proposed statistical channel models for various overhead and underground LV/BPL and MV/BPL channels. Based on this common inherent attribute of either transmission or distribution BPL networks, new unified regression trend line is proposed giving a further boost towards BPL system intraoperability. A consequence of this paper is that it aids in gaining a better understanding of the range and coverage that BPL solutions can achieve; a preliminary step toward the system symbiosis between BPL systems and other broadband technologies in an SG environment.
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Pavón, Wilson, Esteban Inga und Silvio Simani. „Optimal Routing an Ungrounded Electrical Distribution System Based on Heuristic Method with Micro Grids Integration“. Sustainability 11, Nr. 6 (16.03.2019): 1607. http://dx.doi.org/10.3390/su11061607.
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This paper proposes a three-layer model to find the optimal routing of an underground electrical distribution system, employing the PRIM algorithm as a graph search heuristic. In the algorithm, the first layer handles transformer allocation and medium voltage network routing, the second layer deploys the low voltage network routing and transformer sizing, while the third presents a method to allocate distributed energy resources in an electric distribution system. The proposed algorithm routes an electrical distribution network in a georeferenced area, taking into account the characteristics of the terrain, such as streets or intersections, and scenarios without squared streets. Moreover, the algorithm copes with scalability characteristics, allowing the addition of loads with time. The model analysis discovers that the algorithm reaches a node connectivity of 100%, satisfies the planned distance constraints, and accomplishes the optimal solution of underground routing in a distribution electrical network applied in a georeferenced area. Simulating the electrical distribution network tests that the voltage drop is less than 2% in the farthest node.
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Зорин, Евгений Юрьевич, Александр Александрович Чепелюк, Юрий Степанович Грищук und Владимир Владимирович Воинов. „The efficiency analysis of constructive solutions of the capacitive currents compensation plants in medium voltage power distribution grids“. Bulletin of NTU "KhPI". Series: Problems of Electrical Machines and Apparatus Perfection. The Theory and Practice, Nr. 1 (17.04.2019): 11–17. http://dx.doi.org/10.20998/2079-3944.2019.1.03.
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Olama, Mohammed, Jin Dong, Isha Sharma, Yaosuo Xue und Teja Kuruganti. „Frequency Analysis of Solar PV Power to Enable Optimal Building Load Control“. Energies 13, Nr. 18 (04.09.2020): 4593. http://dx.doi.org/10.3390/en13184593.
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In this paper, we present a flexibility estimation mechanism for buildings’ thermostatically controlled loads (TCLs) to enable the distribution level consumption of the majority of solar photovoltaic (PV) generation by local building TCLs. The local consumption of PV generation provides several advantages to the grid operation as well as the consumers, such as reducing the stress on the distribution network, minimizing voltage fluctuations and two-way power flows in the distribution network, and reducing the required battery storage capacity for PV integration. This would result in increasing the solar PV generation penetration levels. The aims of this study are twofold. First, spectral (frequency) analyses of solar PV power generation together with the power consumption of multiple building TCLs (such as heating, ventilation, and air conditioning (HVAC) systems, water heaters, and refrigerators) are performed. These analyses define the bandwidth over which these TCLs can operate and also describe the PV generation frequency bandwidth. Such spectral analyses, in frequency domain, can help identify the flexible components of PV generation that can be consumed by the various TCLs through optimal building load utilization. Second, a quadratic optimization problem based on model predictive control is formulated to allow consuming most of the low and medium frequency content of the PV power locally by building TCLs, while maintaining occupants’ comfort and TCLs’ physical constraints. The solution to the proposed optimization problem is achieved using optimal control strategies. Numerical results show that most of the low and medium frequency content of the PV generation can be consumed locally by building TCLs. The remaining high-frequency content of the PV generation can then be stored/offset using energy storage systems.
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Lazaropoulos, Athanasios G. „Practical Coupled Resonators in Domino Arrangements for Power Transmission and Distribution: Replacing Step-Down Power Transformers and Their Branches across the Power Grid“. Journal of Energy 2013 (2013): 1–25. http://dx.doi.org/10.1155/2013/795835.
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This paper considers the potential of replacing step-down power transformers of the entire power grid as well as part of their transmission line branches with wireless power transfer (WPT) technology components. Exploiting the state-of-the-art evolutions in the fields of WPT technology, coupled resonators in domino arrangements—domino coupled resonator (DCR) configurations—are proposed as suitable technological substitute for step-down power transformers and are investigated in terms of performance metrics such as power transfer efficiency (PTE) and transformation ratio (TR). The contribution of this paper is fivefold. First, an analytical theoretical analysis appropriate to the study of practical DCR configurations is demonstrated. In order to support the DCR configuration replacement venture, a detailed set of assumptions regarding efficient mid- and long-range high-power WPTs as well as related technical issues is first presented. The validity of the theoretical analysis is verified through experimental measurements. Second, applying the proposed theoretical analysis, a wealth of system parameters that mainly influences the PTE and TR of DCR configurations is identified. Their quantitative effect as well as corresponding DCR configuration adjustments are first presented. Third, an approximate method, denoted as approximate chain scattering matrix (CSM) method, is first introduced. Based on the scattering matrix theory formalism, the approximate CSM method is suitable for mid- and long-range DCR configurations when the theoretical analysis becomes computationally slow. The numerical results of approximate CSM method are compared with the respective ones of theoretical analysis validating the extent and the accuracy of approximate CSM method. Fourth, the potential of power transformer replacement with practical DCR configurations is thoroughly investigated in terms of their TRs. A plethora of high-voltage/medium-voltage (HV/MV), MV/low-voltage (MV/LV), and HV/LV power transformers used across the world is investigated verifying their replacement potential with practical DCR configurations in all the cases examined. Fifth, based on a detailed collection of dimensions concerning power transformers and transmission line branches, it is first verified that practical DCR configurations cannot only substitute all step-down power transformers of the today's power grid but also replace entire transmission line branches too. Finally, it is obvious that there is a long journey ahead for WPT technology and its ultramodern DCR configurations to be affordably, widely, reliably, sustainably, and safely adopted in the human society. During these first steps of WPT development for power transmission and distribution, theoretical analyses and visions are necessary. The last cable problem, that is, the seamless power delivery as easily as information is now transmitted through the air, is one of the major technological challenges of the 21st century, and, thus, WPT technology will certainly play key role.
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Pathan, E., S. A. Zulkifli, U. B. Tayab und R. Jackson. „Small Signal Modeling of Inverter-based Grid-Connected Microgrid to Determine the Zero-Pole Drift Control with Dynamic Power Sharing Controller“. Engineering, Technology & Applied Science Research 9, Nr. 1 (16.02.2019): 3790–95. http://dx.doi.org/10.48084/etasr.2465.
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This paper presents a small signal state space modeling of three-phase inverter-based microgrid (MG) system with consideration of improved droop control. The complete system matrices for one distribution source-grid connects to the local load have been elaborated by applying high, medium and low-frequency clusters to the system without considering the switching action on the inverter during power-sharing. Moreover, the final matrices will be used to determine the location of the eigenvalues for the control parameters gains due to dynamic effect of the MG, by observing the root locus graph on cluster identification. Sensitivity analysis of all types of frequency cluster showed that power-sharing control parameters such as load current, source current, and inverter voltage are influencing system stability and must be considered when designing the proportional-integral (PI) control when different load scenarios have been applied from the zero-pole drifting. Those eigenvalues of the system model are indicating the frequency and damping oscillatory components when there is sudden changed at the inverter-grid connection. The matrices’ eigenvalues are being plotted using MATLAB/Simulink to identify system stability region and find the PI controller parameters.
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Botton, Gianluigi, und Gilles L′Espérance. „Effects of accelerating voltage and thickness on the signal-to-noise ratio in Electron Energy Loss Spectroscopy (EELS)“. Proceedings, annual meeting, Electron Microscopy Society of America 47 (06.08.1989): 414–15. http://dx.doi.org/10.1017/s0424820100154044.
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The advantages of medium accelerating voltages (200-400KV) for EELS have been considered to be an improved jump ratio of edges and an improved signal to background ratio for an increased range of thiknesses. However, very little experimental data of the Signal to Noise Ratio (SNR) as a function of incident electron energy (Eo) can be found in the literature. The interest in performing such measurements is to investigate the effect of accelerating voltage on the detectability limits in EELS since SNR can be related to the minimum detectable fraction. In this paper, measurements made on NiO samples show an improved SNR with increasing Eo at a constant thickness value. Changes in the angular distribution of scattering are considered to be responsible for the improved SNR.The NiO sample studied was prepared by evaporation on a copper supporting grid. Uniform areas of different thicknesses (t) caused by the superposition of the film were analysed. Values of mean free path (λ) for NiO were found in the literature. All analyses were carried out with a Philips CM30 and a GATAN 666 Parallel EEL spectrometer (PEELS) coupled to a Link AN10000 MCA. Spectra were transfered on to an external computer for SNR calculations.
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Sarstedt, Marcel, Leonard Kluß, Johannes Gerster, Tobias Meldau und Lutz Hofmann. „Survey and Comparison of Optimization-Based Aggregation Methods for the Determination of the Flexibility Potentials at Vertical System Interconnections“. Energies 14, Nr. 3 (29.01.2021): 687. http://dx.doi.org/10.3390/en14030687.
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The aggregation of operational active and reactive power flexibilities as the feasible operation region (FOR) is a main component of a hierarchical multi-voltage-level grid control as well as the cooperation of transmission and distribution system operators at vertical system interconnections. This article presents a new optimization-based aggregation approach, based on a modified particle swarm optimization (PSO) and compares it to non-linear and linear programming. The approach is to combine the advantages of stochastic and optimization-based methods to achieve an appropriate aggregation of flexibilities while obtaining additional meta information during the iterative solution process. The general principles for sampling an FOR are introduced in a survey of aggregation methods from the literature and the adaptation of the classic optimal power flow problem. The investigations are based on simulations of the Cigré medium voltage test system and are divided into three parts. The improvement of the classic PSO algorithm regarding the determination of the FOR are presented. The most suitable of four sampling strategies from the literature is identified and selected for the comparison of the optimization methods. The analysis of the results reveals a better performance of the modified PSO in sampling the FOR compared to the other optimization methods.
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Bharatiraja, C., und Harish Chowdary V. „Real Time Power Quality Phenomenon for Various Distribution Feeders“. Indonesian Journal of Electrical Engineering and Computer Science 3, Nr. 1 (01.07.2016): 10. http://dx.doi.org/10.11591/ijeecs.v3.i1.pp10-16.
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Power Quality (PQ) brings more challenges to the large- scale and medium scale industries because in the recent years most of them use high efficiency and low energy devices which cause vulnerable PQ disturbances at Point of Common Coupling (PCC). In this paper, the measurement at different times during load condition and analysis of all types of disturbances occurred has been done. When large rated equipments run, the disturbance (harmonics, RMS variations, and switching transients) levels are very high and poor power factor (PF) has also appeared. Due to this poor PF, reactive power consumption in load increases and accordingly total power increases. An electronic device such as LED lights, fluorescent lamps, computers, copy machines, and laser printers also disturb the supply voltage. We are very well known that every PQ problem directly or indirectly must affect economically. Many researchers have investigated PQ audit for over three decades. However these studies and analysis have been done only at simulation level. Hence, the PQ analyzer based study is required to find out the PQ issues at distribution feeders. It will be a valuable guide for researchers, who are interested in the domain of PQ and wish to explore the opportunities offered by these techniques for further improvement in the field of PQ. This paper gives a brief Real Time PQ measurement using PQ analyzer HIOKI PW3198 at Distribution Feeders and it gives an idea to the researcher to optimize problems-related to PQ with respect to the high rated and low rated electric machinery of different feeders at PCC level. This study further extends to analyze the grid disturbances and looks forward to the optimization methods for each individual PQ disturbance.
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Dimovski, Aleksandar, Matteo Moncecchi, Davide Falabretti und Marco Merlo. „PV Forecast for the Optimal Operation of the Medium Voltage Distribution Network: A Real-Life Implementation on a Large Scale Pilot“. Energies 13, Nr. 20 (13.10.2020): 5330. http://dx.doi.org/10.3390/en13205330.
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The goal of the paper is to develop an online forecasting procedure to be adopted within the H2020 InteGRIDy project, where the main objective is to use the photovoltaic (PV) forecast for optimizing the configuration of a distribution network (DN). Real-time measurements are obtained and saved for nine photovoltaic plants in a database, together with numerical weather predictions supplied from a commercial weather forecasting service. Adopting several error metrics as a performance index, as well as a historical data set for one of the plants on the DN, a preliminary analysis is performed investigating multiple statistical methods, with the objective of finding the most suitable one in terms of accuracy and computational effort. Hourly forecasts are performed each 6 h, for a horizon of 72 h. Having found the random forest method as the most suitable one, further hyper-parameter tuning of the algorithm was performed to improve performance. Optimal results with respect to normalized root mean square error (NRMSE) were found when training the algorithm using solar irradiation and a time vector, with a dataset consisting of 21 days. It was concluded that adding more features does not improve the accuracy when adopting relatively small training sets. Furthermore, the error was not significantly affected by the horizon of the forecast, where the 72-h horizon forecast showed an error increment of slightly above 2% when compared to the 6-h forecast. Thanks to the InteGRIDy project, the proposed algorithms were tested in a large scale real-life pilot, allowing the validation of the mathematical approach, but taking also into account both, problems related to faults in the telecommunication grids, as well as errors in the data exchange and storage procedures. Such an approach is capable of providing a proper quantification of the performances in a real-life scenario.
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Sirviö, Katja H., Hannu Laaksonen, Kimmo Kauhaniemi und Nikos Hatziargyriou. „Evolution of the Electricity Distribution Networks—Active Management Architecture Schemes and Microgrid Control Functionalities“. Applied Sciences 11, Nr. 6 (21.03.2021): 2793. http://dx.doi.org/10.3390/app11062793.
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The power system transition to smart grids brings challenges to electricity distribution network development since it involves several stakeholders and actors whose needs must be met to be successful for the electricity network upgrade. The technological challenges arise mainly from the various distributed energy resources (DERs) integration and use and network optimization and security. End-customers play a central role in future network operations. Understanding the network’s evolution through possible network operational scenarios could create a dedicated and reliable roadmap for the various stakeholders’ use. This paper presents a method to develop the evolving operational scenarios and related management schemes, including microgrid control functionalities, and analyzes the evolution of electricity distribution networks considering medium and low voltage grids. The analysis consists of the dynamic descriptions of network operations and the static illustrations of the relationships among classified actors. The method and analysis use an object-oriented and standardized software modeling language, the unified modeling language (UML). Operational descriptions for the four evolution phases of electricity distribution networks are defined and analyzed by Enterprise Architect, a UML tool. This analysis is followed by the active management architecture schemes with the microgrid control functionalities. The graphical models and analysis generated can be used for scenario building in roadmap development, real-time simulations, and management system development. The developed method, presented with high-level use cases (HL-UCs), can be further used to develop and analyze several parallel running control algorithms for DERs providing ancillary services (ASs) in the evolving electricity distribution networks.
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Aziz, Israa, Hai Jin, Ihsan Abdulqadder, Zaid Hussien, Zaid Abduljabbar und Firas Flaih. „A Lightweight Scheme to Authenticate and Secure the Communication in Smart Grids“. Applied Sciences 8, Nr. 9 (01.09.2018): 1508. http://dx.doi.org/10.3390/app8091508.
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Self-reconfiguration in electrical power grids is a significant tool for their planning and operation during both normal and abnormal conditions. The increasing in employment of Intelligent Electronic Devices (IEDs), as well as the rapid growth of the new communication technologies have increased the application of Feeder Automation (FA) in Distribution Networks (DNs). In a Smart Grid (SG), automation equipment, such as a Smart Breaker (SB), is used. Using either a wired or a wireless network or even a combination of both, communication between the Control Center (CC) and SBs can be made. Nowadays, wireless technology is widely used in the communication of DNs. This may cause several security vulnerabilities in the power system, such as remote attacks, with the goal of cutting off the electrical power provided to significant consumers. Therefore, to preserve the cybersecurity of the system, there is a need for a secure scheme. The available literature investments proposed a heavyweight level in security schemes, while the overhead was not considered. To overcome this drawback, this paper presents an efficient lightweight authentication mechanism with the necessary steps to ensure real-time automatic reconfiguration during a fault. As a first stage, authentication will be made between CC and SB, SB then sends the information about its status. To ensure the integrity of the authentication exchange, a hash function is used, while the symmetric algorithm is used to ensure privacy. The applicability of the suggested scheme has been proved by conducting security performance and analysis. The proposed scheme will be injected on ABB medium voltage breaker with the REF 542plus controller. Therefore, the probable benefit of the suggested scheme is the contribution to provide more flexibility for electrical utilities in terms of reducing the overall computational overhead and withstanding to various types of attacks, while also opening new prospects in FA of SGs.
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Ahmad, Fiaz, Akhtar Rasool, Esref Emre Ozsoy, Asif Sabanoviç und Meltem Elitas. „Successive-over-relaxation based recursive Bayesian approach for power system configuration identification“. COMPEL - The international journal for computation and mathematics in electrical and electronic engineering 36, Nr. 4 (03.07.2017): 1043–58. http://dx.doi.org/10.1108/compel-10-2016-0462.
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Purpose The purpose of this paper is to propose successive-over-relaxation (SOR) based recursive Bayesian approach (RBA) for the configuration identification of a Power System. Moreover, to present a comparison between the proposed method and existing RBA approaches regarding convergence speed and robustness. Design/methodology/approach Swift power network configuration identification is important for adopting the smart grid features like power system automation. In this work, a new SOR-based numerical approach is adopted to increase the convergence speed of the existing RBA algorithm and at the same time maintaining robustness against noise. Existing RBA and SOR-RBA are tested on IEEE 6 bus, IEEE 14 bus networks and 48 bus Danish Medium Voltage distribution network in the MATLAB R2014b environment and a comparative analysis is presented. Findings The comparison of existing RBA and proposed SOR-RBA is performed, which reveals that the latter has good convergence speed compared to the former RBA algorithms. Moreover, it is robust against bad data and noise. Originality value Existing RBA techniques have slow convergence and are also prone to measurement noise. Their convergence speed is effected by noisy measurements. In this paper, an attempt has been made to enhance convergence speed of the new identification algorithm while keeping its numerical stability and robustness during noisy measurement conditions. This work is novel and has drastic improvement in the convergence speed and robustness of the former RBA algorithms.
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Muhammad Ridzuan, Mohd, und Sasa Djokic. „Energy Regulator Supply Restoration Time“. Energies 12, Nr. 6 (19.03.2019): 1051. http://dx.doi.org/10.3390/en12061051.
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In conventional reliability analysis, the duration of interruptions relied on the input parameter of mean time to repair (MTTR) values in the network components. For certain criteria without network automation, reconfiguration functionalities and/or energy regulator requirements to protect customers from long excessive duration of interruptions, the use of MTTR input seems reasonable. Since modern distribution networks are shifting towards smart grid, some factors must be considered in the reliability assessment process. For networks that apply reconfiguration functionalities and/or network automation, the duration of interruptions experienced by a customer due to faulty network components should be addressed with an automation switch or manual action time that does not exceed the regulator supply restoration time. Hence, this paper introduces a comprehensive methodology of substituting MTTR with maximum action time required to replace/repair a network component and to restore customer duration of interruption with maximum network reconfiguration time based on energy regulator supply requirements. The Monte Carlo simulation (MCS) technique was applied to medium voltage (MV) suburban networks to estimate system-related reliability indices. In this analysis, the purposed method substitutes all MTTR values with time to supply (TTS), which correspond with the UK Guaranteed Standard of Performance (GSP-UK), by the condition of the MTTR value being higher than TTS value. It is nearly impossible for all components to have a quick repairing time, only components on the main feeder were selected for time substitution. Various scenarios were analysed, and the outcomes reflected the applicability of reconfiguration and the replace/repair time of network component. Theoretically, the network reconfiguration (option 1) and component replacement (option 2) with the same amount of repair time should produce exactly the same outputs. However, in simulation, these two options yield different outputs in terms of number and duration of interruptions. Each scenario has its advantages and disadvantages, in which the distribution network operators (DNOs) were selected based on their operating conditions and requirements. The regulator reliability-based network operation is more applicable than power loss-based network operation in counties that employed energy regulator requirements (e.g., GSP-UK) or areas with many factories that required a reliable continuous supply.
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Müller, Ulf Philipp, Birgit Schachler, Malte Scharf, Wolf-Dieter Bunke, Stephan Günther, Julian Bartels und Guido Pleßmann. „Integrated Techno-Economic Power System Planning of Transmission and Distribution Grids“. Energies 12, Nr. 11 (31.05.2019): 2091. http://dx.doi.org/10.3390/en12112091.
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The energy transition towards renewable and more distributed power production triggers the need for grid and storage expansion on all voltage levels. Today’s power system planning focuses on certain voltage levels or spatial resolutions. In this work we present an open source software tool eGo which is able to optimize grid and storage expansion throughout all voltage levels in a developed top-down approach. Operation and investment costs are minimized by applying a multi-period linear optimal power flow considering the grid infrastructure of the extra-high and high-voltage (380 to 110 kV) level. Hence, the common differentiation of transmission and distribution grid is partly dissolved, integrating the high-voltage level into the optimization problem. Consecutively, optimized curtailment and storage units are allocated in the medium voltage grid in order to lower medium and low voltage grid expansion needs, that are consequently determined. Here, heuristic optimization methods using the non-linear power flow were developed. Applying the tool on future scenarios we derived cost-efficient grid and storage expansion for all voltage levels in Germany. Due to the integrated approach, storage expansion and curtailment can significantly lower grid expansion costs in medium and low voltage grids and at the same time serve the optimal functioning of the overall system. Nevertheless, the cost-reducing effect for the whole of Germany was marginal. Instead, the consideration of realistic, spatially differentiated time series led to substantial overall savings.
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Ji, Shi Qi, Xiao Jie Shi, Zhe Yu Zhang, Wen Chao Cao und Fred Wang. „Benefits of High Voltage SiC Applications in Medium Voltage Power Distribution Grids“. Materials Science Forum 924 (Juni 2018): 875–78. http://dx.doi.org/10.4028/www.scientific.net/msf.924.875.
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This paper evaluates potential benefits of high voltage (HV) SiC devices in medium voltage (MV) distribution grids. The MV microgrid, that HV SiC devices can benefit most, is selected as the “killer application” and focused in this paper. The design and simulation are carried out to compare Si-and SiC-based grid interface converters for the quantitative benefit assessment both at converter level and system level. The SiC-based converter has significant benefits in weight and size, and shows enhanced performance and functionality on power quality, system stability and low voltage ride through (LVRT) as well.
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Hoffmann, Martin W., Stephan Wildermuth, Ralf Gitzel, Aydin Boyaci, Jörg Gebhardt, Holger Kaul, Ido Amihai et al. „Integration of Novel Sensors and Machine Learning for Predictive Maintenance in Medium Voltage Switchgear to Enable the Energy and Mobility Revolutions“. Sensors 20, Nr. 7 (08.04.2020): 2099. http://dx.doi.org/10.3390/s20072099.
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The development of renewable energies and smart mobility has profoundly impacted the future of the distribution grid. An increasing bidirectional energy flow stresses the assets of the distribution grid, especially medium voltage switchgear. This calls for improved maintenance strategies to prevent critical failures. Predictive maintenance, a maintenance strategy relying on current condition data of assets, serves as a guideline. Novel sensors covering thermal, mechanical, and partial discharge aspects of switchgear, enable continuous condition monitoring of some of the most critical assets of the distribution grid. Combined with machine learning algorithms, the demands put on the distribution grid by the energy and mobility revolutions can be handled. In this paper, we review the current state-of-the-art of all aspects of condition monitoring for medium voltage switchgear. Furthermore, we present an approach to develop a predictive maintenance system based on novel sensors and machine learning. We show how the existing medium voltage grid infrastructure can adapt these new needs on an economic scale.
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Dib, M., M. Ramzi und A. Nejmi. „Voltage regulation in the medium voltage distribution grid in the presence of renewable energy sources“. Materials Today: Proceedings 13 (2019): 739–45. http://dx.doi.org/10.1016/j.matpr.2019.04.035.
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Kharchenko, V. A. „The getters in silicon“. Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering 21, Nr. 1 (22.06.2019): 5–17. http://dx.doi.org/10.17073/1609-3577-2018-1-5-17.
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The processes of gettering of fast-diffusing metal impurities and structure defects in silicon, mainly used in the production of integrated circuits, power high-voltage devices, nuclear-doped silicon, are considered. The getters based on structural defects and gas-phase getters based on chlorine-containing compounds are analyzed. It is noted that for the formation of getters on the basis of structural defects, it is necessary to create internal sources for generation of dislocations and formation of precipitate — dislocation clusters. It is shown that dislocations are generated in the mouths of microfractures, which then form a sedentary dislocation grid on the non-working side of the plates. In the second case, defects are created in the area of the plate adjacent to the active layer of the electronic component. The process of creating an internal getter is based on the decomposition of a supersaturated solid oxygen solution in silicon, due to which a complex defect medium consisting of various precipitate-dislocation clusters is formed in the crystal. The packing defect as oxide precipitate with a cloud of Frank’s loops is formed. Two variants of creating an internal getter are considered — first is associated with the distillation of an oxygen impurity from the near-surface region of the plate, the second is associated with a fine adjustment of the distribution of vacancies along the plate thickness. The analysis of the influence of the getter as the defect structure reducing the magnitude of mechanical stress of the beginning of the generation of dislocations, which ultimately can determine the mechanical strength of the silicon wafer.This paper also considers the mechanism of gas-phase medium impurities and defects gettering with the addition of chlorine-containing compounds. It is shown that at elevated temperatures, due to the interaction of silicon atoms with chlorine in the near-surface region of the plate, it is possible to create vacancies that penetrate the sample volume with some probability. As a result, the case DСv > 0, DCi £ 0 is realized, that leads to a change in the composition of microdefects and their density. The examples of practical application of heat treatment in chlorine-containing atmosphere silicon wafer during application of the oxide film, in the case of the target the need for dissolution of the microdefects and of the withdrawal of fast diffusing impurities from the crystal volume, and to prevent the formation of generation-recombination centers in the manufacturing process of devices and in a nuclear doping silicon.
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Kaspirek, Martin, Ladislav Mikulas, David Mezera, Karel Prochazka, Pavel Santarius und Petr Krejci. „Analysis of voltage quality parameters in MV distribution grid“. CIRED - Open Access Proceedings Journal 2017, Nr. 1 (01.10.2017): 517–21. http://dx.doi.org/10.1049/oap-cired.2017.0148.
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Benali, Abdelkrim, Mounir Khiat und Mouloud Denai. „Voltage profile and power quality improvement in photovoltaic farms integrated medium voltage grid using dynamic voltage restorer“. International Journal of Power Electronics and Drive Systems (IJPEDS) 11, Nr. 3 (01.09.2020): 1481. http://dx.doi.org/10.11591/ijpeds.v11.i3.pp1481-1490.
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<p class="Abstract">In this paper, we have presented a simulation study to analyze the power quality of three phases medium voltage grid connected with distribution generation (DG) such as photovoltaic (PV) farms and its control schemes. The system uses two-stage energy conversion topology composed of a DC to DC boost converter for the extraction of maximum power available from the solar PV system based on incremental inductance technique and a three-level voltage source inverter (VSI) to connect PV farm to the power grid. To maintain the grid voltage and frequency within tolerance following disturbances such as voltage swells and sags, a fuzzy logic-based Dynamic Voltage Restorer is proposed. The role of the DVR is to protect critical loads from disturbances coming from the network. Different fault conditions scenarios are tested and the results such as voltage stability, real and reactive powers, current and power factor at the point of common coupling (PCC) are compared with and without the DVR system.</p>
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Kryltcov, Sergei, Aleksei Makhovikov und Mariia Korobitcyna. „Novel Approach to Collect and Process Power Quality Data in Medium-Voltage Distribution Grids“. Symmetry 13, Nr. 3 (12.03.2021): 460. http://dx.doi.org/10.3390/sym13030460.
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The paper is devoted to the development of the structure of a fast and flexible data collecting system based on the proposed approach to measure power quality indicators in three-phase medium-voltage distribution grids with an example of a Mikhailovsky mining and processing plant. The approach utilizes the properties of a space vector, obtained from grid currents and voltages with disturbed waveform, to allow faster extraction of the harmonic components compared to traditional approaches, based on the direct Fourier-transform applied to a line or phase values. During the study, the concept of a universal measurement device was introduced, which allows fast estimation of the following values at the grid node: magnitudes and phases of voltage and current harmonic components, active and reactive power of harmonics and fundamental components, positive and negative instantaneous powers. The structure of interconnected measurement and control units for the considered grid node with simultaneous operation of two active variable frequency drives with active rectifiers was proposed in accordance with a concept of the Internet of things. The benefits of the proposed solution are shown by the example of the model of the grid node with two operating draglines and nonlinear load, which was developed in MATLAB/Simulink software. The proposed approach was utilized to produce distributed references for control systems of grid inverters to compensate nonlinear currents, which allowed to significantly improve THDi of the grid node input power.
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Short, Tom A. „Arc-Flash Analysis Approaches for Medium-Voltage Distribution“. IEEE Transactions on Industry Applications 47, Nr. 4 (Juli 2011): 1902–9. http://dx.doi.org/10.1109/tia.2011.2153810.
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Chen, Xiaofang, Li’an Chen, Dong Wang und Qihao Chen. „Study on safety operation of medium voltage distribution network“. E3S Web of Conferences 260 (2021): 02004. http://dx.doi.org/10.1051/e3sconf/202126002004.
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Aiming at the problem of safe operation in the medium voltage distribution network with neutral point grounding through small resistance, the distribution network model was built, and on this basis, MW-level photovoltaic (PV) system, doubly fed Induction generator (DFIG) wind turbine, permanent magnet synchronous generator (PMSG) wind turbine and energy storage device was connected respectively in this paper. The ground current and earth potential rise was studied when the power was delivered by mistake. The simulation results show that in the system with neutral point grounding through small resistance, whether it is the traditional or the active distribution network, the three-phase power delivery method is more able to ensure the personal safety of power grid operators. However, The access to distributed generator (DG) in the distribution network will have a greater impact on ground current and earth potential rise in the case of three-phase power delivery. Especially when the ground current and earth potential rise will increase after DG connected to distribution network, which is still likely to pose a threat to personal safety and needs further research.
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Kuzmina, I. A. „Feasibility Assessment of Urban Electricity Distribution Networks Transition to the Voltage Level of 20 kV“. Mechanical Engineering and Computer Science, Nr. 12 (04.01.2018): 57–65. http://dx.doi.org/10.24108/1217.0001358.
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The article gives a feasibility assessment for increasing a voltage level of the urban electricity distribution networks from 6 and 10 kV to 20 kV.The emphasis is on the urban electricity distribution network in Moscow. It is noted that by now the reliability, efficiency and automation indicators of Moscow electrical grids are substantially lower than those of Europe, America, etc. The electrical grids in Moscow have a high wear and tear of equipment, a historically developed non-optimal structure, and a high loading level. In recent years, the situation has been significantly improved due to numerous government programs for the development of the electric power industry.It was noted that the high rate of development in Moscow resulted in a significantly increasing density of power loads. So modernisation of grids is a necessary-and-proper step to deliver electric power of good quality and in appropriate volume to all consumers. As the most promising option of such modernisation, the article’s proposal is to increase a voltage level of the electrical grid of medium voltage from 6 and 10 kV to 20 kV.The main advantages of the electrical grid transition to the higher voltage level is an increased power grid capacity and reduced losses of voltage and electric power when transmitting through the electrical grid elements. The article presents some calculations to prove decreasing several times losses in medium voltage cable lines. The shortcoming of the transition to an electrical grid of 20 / 0.4 kV is significant implementation costs, most of which will lead to increasing tariff for consumers.The experience of other countries examined in the article proves that increasing voltage level of the distribution network in Moscow and other megacities is expedient. At the same time, a gradual introduction of 20 / 0.4 kV substations to the electrical grid structure with a gradual unloading and elimination of 10 kV electrical grid elements is expected. The article appeals to successful experience available in the transition of large industrial enterprises to a voltage level of 20 / 0.4 kV.