Статті в журналах: "REACTIVE POWER LIMIT"

1

Hiskens, I. A., and B. B. Chakrabarti. "Direct calculation of reactive power limit points." Fuel and Energy Abstracts 37, no. 3 (May 1996): 192. http://dx.doi.org/10.1016/0140-6701(96)88682-6.

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2

Hiskens, I. A., and B. B. Chakrabarti. "Direct calculation of reactive power limit points." International Journal of Electrical Power & Energy Systems 18, no. 2 (February 1996): 121–29. http://dx.doi.org/10.1016/0142-0615(95)00058-5.

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3

Sundaravazhuthi*, V., Dr A. Alli Rani, and M. Manoj Kumar. "Raise Voltage Stability Limit of a Power System using Reactive Power Compensation Technique." International Journal of Innovative Technology and Exploring Engineering 8, no. 12 (October 30, 2019): 2931–34. http://dx.doi.org/10.35940/ijitee.k1752.1081219.

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Анотація:

In recent years, voltage stability problems have been increasing since power systems operate close to stability limits. The voltage stability problem of a power system is associated with a rapid voltage drop due to heavy system load and it occurs because of inadequate reactive power support at some critical bus. One of the serious consequences of the voltage stability is a system blackout, and this has received more attention in recent years. Accurate determination of stability limit and amount of reactive power injection to stabilize is important.This paper proposes to determine voltage stability margin of a critical bus and also provide amount of reactive power injection to the bus particularly during overload, a simple two bus equivalent model of the power system is used to determine the maximum apparent power for different power factors. Any required apparent power can directly obtained by correcting the reactive power at critical bus. Experimental results support our theoretical findings.

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4

Hu, Shu Ju, Ling Ling Wang, and Ya Deng. "Analysis on Power Output Capability and its Power Control Strategy of DFIG Wind Turbine under Unbalanced Grid Voltage." Applied Mechanics and Materials 448-453 (October 2013): 1819–24. http://dx.doi.org/10.4028/www.scientific.net/amm.448-453.1819.

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Wind turbines are required by gird codes that active and reactive power should be fed into power grid during gird faults such as voltage sags. Power output capability is important for DFIG wind turbine to provide active and reactive power support. Constraints of stator, rotor maximum current and maximum output voltage of rotor-side converter (RSC) of DFIG are considered to analyze stator power output limit of the DFIG under unbalanced voltage sags, and newton-raphson method is used to solve the power limits, then the power control strategy based on power limit analysis is proposed. Simulation, calculation and comparison are carried out by a 1.5MW DFIG wind turbine model, and the effectiveness of the analysis and the proposed control strategy is verified.

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5

Pavlović, Jelena, Bojan Radojičić, Lazar Stančić, Jasna Dragosavac, Sava Dobričić, and Žarko Janda. "Algorithm of reactive power dispatching "per generator" realization on TPP Nikola Tesla A." Zbornik radova Elektrotehnicki institut Nikola Tesla, no. 32 (2022): 113–23. http://dx.doi.org/10.5937/zeint32-41760.

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The algorithm of reactive power dispatching "per generator" realization is presented in the paper. Dispatching "per generator" and "per grid" are two modes of reactive power dispatching used by coordinated reactive power and voltage regulator (GRRS). Reactive power dispatching "per generator" ensures equal heating of the generators, while dispatching "per grid" ensures maximal reactive power reserve when generated reactive power either increases, or decreases. Reactive power dispatching "per generator" is more complex for realization because the dispatching criterion may have wider generator's reactive power operation area than the working capability curve. In these cases, the additional limiting of the generator reactive power is necessary, while other generators take over the remaining reactive power, still considering the reactive power dispatching criteria "per generator" and the limits of the remaining generators. Both reactive power dispatching modes are presented in two examples, while operating near and far from the limit area. Eventually, as the verification of the algorithm and its realization, the operating results of GRRS while dispatching "per generator" is active, are presented.

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6

Tamimi, Behnam, Claudio A. Canizares, and Sadegh Vaez-Zadeh. "Effect of Reactive Power Limit Modeling on Maximum System Loading and Active and Reactive Power Markets." IEEE Transactions on Power Systems 25, no. 2 (May 2010): 1106–16. http://dx.doi.org/10.1109/tpwrs.2009.2036798.

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7

Liu, Guan Qi, Long Shao, and Shou Shu Guan. "The Research of Reactive Power Output of Doubly-Fed Induction Generator when Large-Scale Wind Power Integration." Applied Mechanics and Materials 380-384 (August 2013): 3061–64. http://dx.doi.org/10.4028/www.scientific.net/amm.380-384.3061.

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The technology of large-scale wind power connected to grid is a key technology in the application of wind power. However, the large-scale wind power will cause the negative effect on the voltage of grid. So, the regulation of reactive power is necessary, which can stabilize the voltage level of the grid. The doubly-fed induction generators (DFIG) themselves own the ability of providing reactive power. Considering the reactive power demand when the power grid is operating, and then rationally allocating static and dynamic reactive power compensation equipment, the operational efficiency can be improved. The particle analyzes the reactive power limit of DFIG, considering the limit of stator and rotor. In this way, the reactive power compensation capacity of DFIG is used first, the use of reactive power compensation equipments are greatly reduced, so the economy of the wind farm is obviously improved.

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8

Kataoka, Yoshihiko, and Yukio Shinoda. "Voltage Stability Limit of Electric Power System with Reactive Power Constraints on Generators." IEEJ Transactions on Power and Energy 123, no. 6 (2003): 704–17. http://dx.doi.org/10.1541/ieejpes.123.704.

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9

Kataoka, Y., and Y. Shinoda. "Voltage Stability Limit of Electric Power Systems With Generator Reactive Power Constraints Considered." IEEE Transactions on Power Systems 20, no. 2 (May 2005): 951–62. http://dx.doi.org/10.1109/tpwrs.2005.846080.

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10

Abdelaziz, Morad Mohamed Abdelmageed. "Effect of Detailed Reactive Power Limit Modeling on Islanded Microgrid Power Flow Analysis." IEEE Transactions on Power Systems 31, no. 2 (March 2016): 1665–66. http://dx.doi.org/10.1109/tpwrs.2015.2412690.

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11

Xu, Xue Yong, Pan Zhou, Qi Zhe Huang, Chun Ming Deng, Meng Meng Shi, and Gang Xue. "Optimization of Voltage and Reactive Power in Regional Power Network Based on MCR." Advanced Materials Research 986-987 (July 2014): 394–99. http://dx.doi.org/10.4028/www.scientific.net/amr.986-987.394.

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Along with the increasing use of cables in power grid and the increasing ration of distributed power sources’ synchronization, such as small hydropower’s synchronization, increasing the reactive power transmission on the line, make it difficult to achieve the balance of reactive hierarchical partition. Take a certain region’s power grid for actual examples, after the installation of magnetic control reactor (MCR), using immune genetic algorithm (IGA) to coordinate the capacity of magnetic control reactor and the existing reactive power resources, the results show that the magnetic control reactor does much good to absorb the system’s excessive reactive power and limit the voltage’s increasing.

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12

Zhu, Yingfeng, Xiaosu Xie, Dong Yang, Song Gao, Weichao Zhang, and Xunkui Yuan. "Simulation of reactive power regulation of DFIG." E3S Web of Conferences 233 (2021): 01025. http://dx.doi.org/10.1051/e3sconf/202123301025.

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Doubly fed induction generator (DFIG) wind power generation system is widely used in wind farm all over the world. Reactive power can be generated both in grid-side converter and generator-side converter of DFIG. In this paper, working principle and control method of DFIG are introduced, and the reactive power limit of DFIG is derived, finally reactive power regulation is simulated in Simulink.

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13

Lin, Zhiyuan, Fei Tang, Caiyang Yu, Haibo Li, Lei Zhong, Xinyu Wang, and Huipeng Deng. "Reactive Power Compensation Strategy of the Electric Vehicle Connected to the Distribution Network in the Limit State Considering Voltage Constraint." Sustainability 15, no. 11 (May 26, 2023): 8634. http://dx.doi.org/10.3390/su15118634.

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To solve the voltage stability problem of electric vehicles connected to the distribution network in the limit state, a reactive power compensation strategy based on the holomorphic embedding method and electrical distance is proposed. Firstly, the load model of the electric vehicle charging station is constructed, and the limit of the charging power of the electric vehicle connected to a certain bus is obtained. Then, the power flow embedding equation of the power system is constructed by the holomorphic embedding method, and the analytical expression of the voltage rational function is introduced based on the Padé approximation algorithm. The voltage collapse point is solved by the distribution of zeros and poles of the rational function. Then, a method of reactive power and voltage control partition based on electrical distance is proposed. According to the principle of weak regional coupling and strong interval coupling, the power system is divided into several regions by spectral clustering and a k-means clustering algorithm. The order of the voltage stability margin value s is obtained by connecting the limit charging power to each bus of the power system. In this paper, the reactive power compensation strategy proposes to add reactive power compensation devices to the buses with the weakest voltage stability margin in different zones. Finally, compared with other reactive power compensation strategies 1 and 2, the reactive power compensation strategy provided in this paper is increased by 1.626121813 and 1.160494345 times, respectively. The superiority of this method is verified by simulation.

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14

Chen, Shuhao, Ting Yuan, and Fei Lin. "Research on Reactive Voltage Control of Distribution Network with Distributed Photovoltaic Sources." Journal of Physics: Conference Series 2310, no. 1 (October 1, 2022): 012025. http://dx.doi.org/10.1088/1742-6596/2310/1/012025.

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Abstract Aiming at the problem that the voltage of multiple nodes exceeds the limit after the distributed photovoltaic source is connected, a reactive voltage control method of distribution network is proposed. It modeled the distribution network system with distributed photovoltaic sources, determined the maximum photovoltaic output and adjustable amount, and calculated the power flow. The line loss can be obtained from the node voltage and rated power, and the power distribution of each branch of the whole network can be further obtained. This paper analyzed the influence of photovoltaic power access on the voltage quality of the distribution network from the perspective of power. It calculated the reactive output power of reactive power compensation equipment of upstream and downstream nodes. In this paper, the active power of distributed generation is locally reduced at each out-of-limit node to control the voltage. The experimental results show that the proposed method can effectively improve the relationship between photovoltaic output and voltage, and realize the correction of photovoltaic regulation. Therefore, it can reduce the risk of voltage out of limit and improve the voltage quality.

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15

Zhang, Song Tao, Gong Bao Wang, and Hui Bo Wang. "Application of Tabu-Genetic Algorithm in Reactive Power Optimization." Advanced Materials Research 1006-1007 (August 2014): 1021–25. http://dx.doi.org/10.4028/www.scientific.net/amr.1006-1007.1021.

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By using tabu search algorithm which has strong local search ability as mutation operator of genetic algorithm, the tabu-genetic algorithm is designed for reactive power optimization in this paper, the strong global search ability of genetic algorithm and strong local search ability of tabu search algorithm is combined, the disadvantage of weak local search ability of genetic algorithm is conquered. Otherwise, the over limit of population is recorded and filtered, to ensure the final individual is under limit and effective. The tabu-genetic algorithm and simple genetic algorithm are used for simulation of IEEE 14-bus system 500 times, the results indicate that the performance of the tabu-genetic algorithm is much better than the simple genetic algorithm, its local search ability is improved obviously, and the active power loss is reduced more.

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16

Duong, Thanh Long, Minh Quan Duong, Van-Duc Phan, and Thang Trung Nguyen. "Optimal Reactive Power Flow for Large-Scale Power Systems Using an Effective Metaheuristic Algorithm." Journal of Electrical and Computer Engineering 2020 (March 1, 2020): 1–11. http://dx.doi.org/10.1155/2020/6382507.

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In this paper, stochastic fractal search method (SFS) is employed for solving the optimal reactive power flow (ORPF) problem with a target of optimizing total active power losses (TPL), voltage deviation (VD), and voltage stability index (VSI). SFS is an effective metaheuristic algorithm consisting of diffusion process and two update processes. ORPF is a complex problem giving challenges to applied algorithms by taking into account many complex constraints such as operating voltage from generators and loads, active and reactive power generation of generators, limit of capacitors, apparent power limit from branches, and tap setting of transformers. For verifying the performance, solutions of IEEE 30 and 118-bus system with TPL, VD, and VSI objectives are found by the SFS method with different control parameter settings. Result comparisons indicate that SFS is more favorable than other methods about finding effective solutions and having faster speed. As a result, it is suggested that SFS should be used for ORPF problem, and modifications performed on SFS are encouraged for better results.

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17

Wang, Xiangdong, Lei Wang, Wenfa Kang, Tiecheng Li, Hao Zhou, Xuekai Hu, and Kai Sun. "Distributed Nodal Voltage Regulation Method for Low-Voltage Distribution Networks by Sharing PV System Reactive Power." Energies 16, no. 1 (December 28, 2022): 357. http://dx.doi.org/10.3390/en16010357.

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With the intensive integration of photovoltaic (PV) sources into the low-voltage distribution networks (LVDN), the nodal voltage limit violations and fluctuation problem cause concerns on the safety operation of a power system. The intermittent, stochastic, and fluctuating characteristics of PV output power leads to the frequent and fast fluctuation of nodal voltages. To address the voltage limit violation and fluctuation problem, this paper proposes a distributed nodal voltage regulation method based on photovoltaic reactive power and on-load tap changer transformers (OLTC). Using the local Q/V (Volt/Var) feedback controller derived from the grid sensitivity matrix, the voltage magnitude information is adopted to adjust the output of PV systems. Moreover, in order to share the burden of voltage regulation among distributed PV systems, a weighted distributed reactive power sharing algorithm is designed to achieve the voltage regulation according to the rated reactive power. Theoretical analysis is provided to show the convergence of the proposed algorithm. Additionally, the coordination strategy for distributed PV systems and OLTC is provided to reduce the reactive power outputs of PV systems. Five simulation case studies are designed to show the effectiveness of the proposed voltage regulation strategy, where the voltage regulation and proportional reactive power sharing can be achieved simultaneously.

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18

Sutjipto, Rachmat, Ika Noer Syamsiana, and Widya Pratiwi. "Analisis Pengaruh Pengaturan Sudut Penyalaan Thyristor Pada Tegangan Eksitasi Terhadap Keluaran Daya Reaktif Generator di PT.PJB PLTU Gresik Unit 3." ELPOSYS: Jurnal Sistem Kelistrikan 8, no. 3 (November 22, 2021): 53–58. http://dx.doi.org/10.33795/elposys.v8i3.77.

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The process of changing mechanical energy into electrical energy is carried out by a synchronous generator using an excitation system that functions to supply a DC source to the generator field winding. In this study, the excitation system used is a static excitation system that uses a transformer and several thyristors connected in a bridge configuration. The excitation system is then implemented on a generator with a capacity of 200 MVA / 15 kV using the MATLAB Simulink R2017b simulation. By using the above circuit, the thyristor ignition angle setting can be adjusted so that it can adjust the excitation voltage and obtain the appropriate excitation current to maintain the stability of the generator output voltage. The simulation was carried out with variations in generator load and using 2 different types of excitation settings. The first setting is to set the thyristor ignition angle to 30° with t=10 ms, at this setting the generator can maintain a stable V out value with a voltage regulation limit of ±5% and the reactive power that can be generated by the generator is +50 MVAr and - 40 MVAr. When given a constant excitation at an angle of 35° with t=1 ms, the value of Vout exceeds the expected regulatory limit and the resulting reactive power limit is between +60 MVAr and -100 MVAR where the reactive power does not match the load requirements. This can have an impact on the interconnection system, namely when the reactive power of the generator is greater than the load requirement, the generator with a smaller reactive power will absorb reactive power in the interconnection system and can disrupt the stability of the interconnection network.

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19

Anichebe, I. B., and A. O. Ekwue. "Improvement of bus voltage profiles of Nigerian power network in the presence of Static Synchronous Compensator (STATCOM) and Doubly Fed Induction Generator (DFIG)." Nigerian Journal of Technology 39, no. 1 (April 3, 2020): 228–37. http://dx.doi.org/10.4314/njt.v39i1.26.

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Frequent blackouts and unstable supply of electricity show that the voltage instability problem has been one of the major challenges facing the power system network in Nigeria. This study investigates the voltage stability analysis of the Nigerian power network in the presence of renewable energy sources; FACTS device is used as a voltage controller. A 330kV, 28-bus power system network was studied using the PSS/E software-based Newton-Raphson load-flow technique. The results show that 10 out of the 28 buses had voltages lying below the statutory limit of 0.95 ≤ 1.05 p.u. The application of STATCOM and DFIG devices on two of the weakest buses restored the voltages to acceptable statutory limits. The total active and reactive power losses were reduced to 18.76% and 18.82% respectively. Keywords: Voltage stability analysis; Integration of renewable energy sources; FACTS controllers, Reactive Power, Power Flow.

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20

Schultis, Daniel-Leon, and Albana Ilo. "Behaviour of Distribution Grids with the Highest PV Share Using the Volt/Var Control Chain Strategy." Energies 12, no. 20 (October 12, 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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21

Tian, Na, Tongfei Cui, Shiyang Rong, Jifeng Liang, and Jingyuan Dong. "Dynamic Reactive Power Optimization Configuration of New Energy Power Station Based on Fault Limit Removal Time." Journal of Physics: Conference Series 2474, no. 1 (April 1, 2023): 012012. http://dx.doi.org/10.1088/1742-6596/2474/1/012012.

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Abstract The large-scale construction of long-distance, high voltage level transmission projects and sustained load demand increase negatively influence transient voltage stability. A certain amount of dynamic Var compensation at the receiving end of the power grid can significantly improve the stability. Most new energy power plants, such as wind power, and photovoltaic generation, have installed dynamic Var compensation devices. The potential for safety and stability control should be fully exploited. In this paper, it is concluded that the critical fault clearing time is the main index to measure the transient voltage stability of the system, and the critical fault clearing time has been extended by allocating dynamic Var compensation. According to these conclusions, a method for optimal allocation of dynamic Var compensation to improve critical fault clearing time is proposed. The method has determined the optimal capacity and the installation point. The effectiveness of the proposed method is illustrated through simulations on the actual power grid.

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22

Bhargavi, R. Naveena, and R. Anurup Bhargavi. "Optimal Location and Sizing of Reactive Power Compensation Devices for Voltage Stability Improvement of Radial Power Systems." ECS Transactions 107, no. 1 (April 24, 2022): 367–75. http://dx.doi.org/10.1149/10701.0367ecst.

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With the advancement in technology, the electricity demand is increasing day by day. Power supply utilities are facing the problem to expand their network owing to the problems like availability of land in urban areas and Right of Way (ROW). Due to these problems, many of the existing lines are operating nearer to their thermal stability limit. Maintaining the voltage within the limits will be a challenging task for the utilities. Increased loading of the lines is making the power system to the verge of voltage stability. Many indices are proposed in the literature for predicting the voltage stability of the system. In this paper, L-Index is used for voltage stability analysis of the radial distribution system. L-Index sensitivity method is used to the locate and size the reactive power compensation devices. The effectiveness of L-Index sensitivity method on the larger power system like IEEE-33 bus system is presented in this paper and simulation studies are performed using MATLAB/SIMULINK.

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23

Chen, Shaoyu, Zhen Li, Bolong Shi, Xianting Ren, and SuiRong Li. "Research on reactive power and voltage coordinated control of intelligent distributed network." Journal of Physics: Conference Series 2427, no. 1 (February 1, 2023): 012047. http://dx.doi.org/10.1088/1742-6596/2427/1/012047.

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Abstract with the continuous expansion of the scale of distributed new energy grid-connected power generation in the distribution network and the continuous improvement of penetration rate, the problem of distribution network voltage out of limit caused by distributed new energy grid connected can not be ignored. This paper analyzes the basic principle of voltage out of limit caused by the connection of distributed new energy sources to the distribution network,and analyzes the factors affecting the reactive power and voltage of the active distribution network with distributed new energy sources through BPA simulation, The compensation effects of the distributed series reactor and distributed shunt reactor are compared.

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24

Bondar, Oleh, Mikola Kostin, Andrei Mukha, Olha Sheikina, and Svitlana Levytska. "Fryze reactive power of trams in effective stochastic recuperation processes." MATEC Web of Conferences 294 (2019): 01006. http://dx.doi.org/10.1051/matecconf/201929401006.

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Urban electric transport system, particularly tram systems, is not a direct current system not only in traction mode but in regenerative modes as both voltage on a collector and regenerative current are stochastic abruptly variable processes. The above- mentioned facts determine availability of Fryze’s reactive power in this system that flows from a railway substation to trams, leads to incidental losses of energy and significantly reduces its quality. So evaluation of power effectiveness of the system in electrical trams operation is impossible without determining the level of reactive power in this system. We have analytical expression of reactive power by Fryze. Numerical calculations for trams type T3D and T4D in regenerative braking modes are done. Probabilistic statistical data processing operation of reactive power expressions is done. It is determined that reactive power changes in the limit of 10…100 kilo-volt ampere reactive with mathematical expectation – 37,0 kilo-volt ampere reactive. Statistical allocation of random power values are different. Numerical calculations of incidental losses, energy of recuperation are done and they range supplementary – 20% from total losses. It is stated that coefficient of reactive power of system route of trams is exceeding permissible value 0,25.

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25

Schultis, Daniel-Leon, and Albana Ilo. "Effect of Individual Volt/var Control Strategies in LINK-Based Smart Grids with a High Photovoltaic Share." Energies 14, no. 18 (September 8, 2021): 5641. http://dx.doi.org/10.3390/en14185641.

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The increasing share of distributed energy resources aggravates voltage limit compliance within the electric power system. Nowadays, various inverter-based Volt/var control strategies, such as cosφ(P) and Q(U), for low voltage feeder connected L(U) local control and on-load tap changers in distribution substations are investigated to mitigate the voltage limit violations caused by the extensive integration of rooftop photovoltaics. This study extends the L(U) control strategy to X(U) to also cover the case of a significant load increase, e.g., related to e-mobility. Control ensembles, including the reactive power autarky of customer plants, are also considered. All Volt/var control strategies are compared by conducting load flow calculations in a test distribution grid. For the first time, they are embedded into the LINK-based Volt/var chain scheme to provide a holistic view of their behavior and to facilitate systematic analysis. Their effect is assessed by calculating the voltage limit distortion and reactive power flows at different Link-Grid boundaries, the corresponding active power losses, and the distribution transformer loadings. The results show that the control ensemble X(U) local control combined with reactive power self-sufficient customer plants performs better than the cosφ(P) and Q(U) local control strategies and the on-load tap changers in distribution substations.

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26

Li, Gan, Li Jie Ding, and Dan Dan Li. "SVG Graphical Analysis Tool Online Regional Reactive Power Optimization System Development." Advanced Materials Research 986-987 (July 2014): 2073–77. http://dx.doi.org/10.4028/www.scientific.net/amr.986-987.2073.

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Online region reactive power optimization is used to reduce power bus voltage operation over limit and reduce net loss for the economy to ensure that the power grid of great significance. SVG graphics file is a standard file format used by our dispatching operation, analysis file and basic information within the file corresponds to reactive power optimization system can guarantee the system reactive power optimization of interactive graphics capability and versatility. In this paper, we design and development of a SVG graphics file parsing tool that can automatically complete the import SVG, structural analysis, and text parsing; graphics and connectivity analysis to ensure the accuracy of the topology; the module contains a custom chart for human-computer interaction element, Element Properties and topological analysis and dynamic trend function, to meet human-computer interaction and reactive power optimization computing needs. This module has been applied to a region with reactive power optimization system, with good results.

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27

Baharizadeh, Mehdi, Hamidreza Karshenas, and Jafar Ghaisari. "Limit Cycle Occurrence During Reactive Power Generation by Interlinking Converter in Hybrid Microgrids." Canadian Journal of Electrical and Computer Engineering 39, no. 2 (2016): 181–89. http://dx.doi.org/10.1109/cjece.2016.2531904.

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28

Badrudeen, Tayo Uthman, Funso Kehinde Ariyo, Ayodeji Olalekan Salau, and Sepiribo Lucky Braide. "Analysis of a new voltage stability pointer for line contingency ranking in a power network." Bulletin of Electrical Engineering and Informatics 11, no. 6 (December 1, 2022): 3033–41. http://dx.doi.org/10.11591/eei.v11i6.4266.

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Improper management of reactive power in a power network could lead to voltage instability. This paper presents a well-detailed study on voltage instability due to violation of power equilibrium in a power network and introduces a new voltage stability pointer (NVSP). The proposed NVSP is developed from a reduced 2-bus interconnected network to predict the sensistivity of voltage stability to reactive power variation. The simulation results from MATLAB were evaluated on IEEE 14-bus test system. The contingency ranking was achieved by varying the reactive power on the load buses to its maximum loading limit. The maximum reactive power point was taken at each load bus and the critical lines were ranked according to their vulnerability to voltage collapse. The results were compared with other notable voltage stability indices. The results prove that the NVSP is an essential tool in predicting voltage collapse.

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29

NAYFEH, ALI H., AHMAD M. HARB, and CHAR-MING CHIN. "BIFURCATIONS IN A POWER SYSTEM MODEL." International Journal of Bifurcation and Chaos 06, no. 03 (March 1996): 497–512. http://dx.doi.org/10.1142/s0218127496000217.

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Bifurcations are performed for a power system model consisting of two generators feeding a load, which is represented by an induction motor in parallel with a capacitor and a combination of constant power and impedance PQ load. The constant reactive power and the coefficient of the reactive impedance load are used as the control parameters. The response of the system undergoes saddle-node, subcritical and supercritical Hopf, cyclic-fold, and period-doubling bifurcations. The latter culminate in chaos. The chaotic solutions undergo boundary crises. The basin boundaries of the chaotic solutions may consist of the stable manifold of a saddle or an unstable limit-cycle. A nonlinear controller is used to control the subcritical Hopf and the period-doubling bifurcations and hence mitigate voltage collapse.

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30

Tazky, Matej, Michal Regula, and Alena Otcenasova. "Impact of Changes in a Distribution Network Nature on the Capacitive Reactive Power Flow into the Transmission Network in Slovakia." Energies 14, no. 17 (August 27, 2021): 5321. http://dx.doi.org/10.3390/en14175321.

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The main emphasis in the operation of an electricity system is placed on its safe and reliable operation. The flow of reactive power in a network can affect voltage conditions in individual nodes of the transmission system. In recent years, there have been changes in the network that have resulted in increased capacitive reactive power flows from lower voltage levels to higher ones. These flows can cause the voltage to rise above the limit. This paper examines recent changes in the reactive power transmission in the network, especially at lower voltage levels. The possible impact of these changes on the flow of capacitive reactive power at higher voltage levels is analyzed. This paper also presents a description and the simulated impact of power lines at different voltage levels on reactive power flows. Real measurements of different types of consumers at the low-voltage (LV) level are analyzed. Finally, a simulation model was created to simulate the impact of a customer’s power contribution to the reactive power flows from the point of view of a 110 kV voltage node. This node is characterized as a supply point.

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31

Zhong, Qidi, Yulong Ma, Zhichuang Li, Yajun Lu, and Ming Li. "Reactive Power Control and SVG Coordinated Control Method for HVDC Transmission System." Journal of Physics: Conference Series 2532, no. 1 (June 1, 2023): 012007. http://dx.doi.org/10.1088/1742-6596/2532/1/012007.

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Abstract This paper proposes a reactive power and SVG coordinated control method for a HVDC transmission system. The method includes calculating the reactive power ΔQ exchanged between the converter station and the AC system. Set the dead zone range of ΔQ and limit the output of ΔQ. Set the restriction condition of SVG’s ability to adjust and judge whether the reactive power emitted by SVG is restricted. Based on whether the reactive power sent by the SVG is limited and the limitation results of ΔQ, the input of the PI controller in the QPC module is calculated to complete the reactive power, and SVG coordinated control process. When this control method is adopted, the operating time of the converter greater than the rated angle is significantly reduced, the loss of the converter is effectively reduced. Meanwhile, the DC voltage rise and fall are stabilized, and the AC voltage fluctuations due to the passive switching are greatly reduced.

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32

Yan, Tian Xiang, Xiao Lan Xie, Xin Yu Chen, and Peng Niu. "Analysis of Thyristor Switched Three-Phase Capacitor." Advanced Materials Research 722 (July 2013): 311–16. http://dx.doi.org/10.4028/www.scientific.net/amr.722.311.

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Анотація:

it can limit the reactive power transmission to improve the voltage quality of power grid by installing parallel capacitors for reactive power compensation. But due to presence of transient transition process during power capacitors switching, it will seriously affect the service life of power capacitors and the safe operation of power system if the switching process of capacitors is not properly controlled. Firstly, this article described the fundamental principle and switching conditions of Thyristor Switched Capacitor (TSC). Secondly, the selection of switching time was analyzed for Thyristor Switched Three-phase Capacitor (TSTC). Finally, the simulation for TSTC was carried out by using MATLAB to verify the feasibility of analysis.

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33

Wu, Hong Mei, and Wen Ting Hui. "Study of a Multi Objective Reactive Power Compensation Device Considering Fault Current Limiting." Applied Mechanics and Materials 397-400 (September 2013): 1868–72. http://dx.doi.org/10.4028/www.scientific.net/amm.397-400.1868.

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Анотація:

With the increasing demands of power quality, high-quality power supply has become a necessary condition of modern social life. Power quality problems include voltage sag/swell, voltage unbalance and harmonics. To solve the above problem, a multi objective reactive power compensation device considering fault current limiting is designed, which can provide a certain degree of reactive power compensation to solve multi-objective system powered composite power quality problems during the normal working of the power system, and be able to quickly to limit the short-circuit current mode switching when power system under fault conditions. Finally, on the basis of theoretical analysis, experiments and simulations confirmed the correctness and effectiveness of the control strategy.

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34

Sakti, Fredi Prima, and Jimmy Trio Putra. "Optimal Reactive Power Dispatch untuk Meminimalkan Rugi Daya Menggunakan Flower Pollination Algorithm." Jurnal Teknik Elektro 11, no. 2 (December 20, 2019): 36–43. http://dx.doi.org/10.15294/jte.v11i2.21680.

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This paper presents the Flower Pollination Algorithm (FPA) metaheuristic used to solve the Optimal Reactive Power Dispatch (ORPD) problem. ORPD is a non-linear optimization problem in the electric power system that regulates the generation of reactive power at the generator to minimize the real power loss on the transmission line while maintaining all parameters at the allowable value. In this case the FPA algorithm is used to find the minimum power loss by adjusting the voltage magnitude value of the generator, the transformer tap settings, and the reactive power compensator value in the system while maintaining the magnitude of the bus voltage, active and reactive power at the generator, and the channel capacity remains at its safe limit. ORPD is applied to the IEEE-30 Bus system test consisting of 8 generating units, 4 transformers, 9 reactive power compensators and 41 channels. The system has a load of 283.4 MW and 126.2 MVAR. The results after being optimized using FPA shows the power loss in the channel is reduced to 4,895 MW or reduced by 15.89%. The results of optimization using FPA showed better results compared to Genetic Algorithm and Particle Swarm Optimization.

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35

Wilson, David G., Rush D. Robinett, Giorgio Bacelli, Ossama Abdelkhalik, and Ryan G. Coe. "Extending Complex Conjugate Control to Nonlinear Wave Energy Converters." Journal of Marine Science and Engineering 8, no. 2 (January 30, 2020): 84. http://dx.doi.org/10.3390/jmse8020084.

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This paper extends the concept of Complex Conjugate Control (CCC) of linear wave energy converters (WECs) to nonlinear WECs by designing optimal limit cycles with Hamiltonian Surface Shaping and Power Flow Control (HSSPFC). It will be shown that CCC for a regular wave is equivalent to a power factor of one in electrical power networks, equivalent to mechanical resonance in a mass-spring-damper (MSD) system, and equivalent to a linear limit cycle constrained to a Hamiltonian surface defined in HSSPFC. Specifically, the optimal linear limit cycle is defined as a second-order center in the phase plane projection of the constant energy orbit across the Hamiltonian surface. This concept of CCC described by a linear limit cycle constrained to a Hamiltonian surface will be extended to nonlinear limit cycles constrained to a Hamiltonian surface for maximum energy harvesting by the nonlinear WEC. The case studies presented confirm increased energy harvesting which utilizes nonlinear geometry realization for reactive power generation.

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36

Zubiaga, Markel, Alain Sanchez-Ruiz, Eneko Olea, Eneko Unamuno, Aitor Bilbao, and Joseba Arza. "Power Capability Boundaries for an Inverter Providing Multiple Grid Support Services." Energies 13, no. 17 (August 20, 2020): 4314. http://dx.doi.org/10.3390/en13174314.

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It is getting more common every day to install inverters that offer several grid support services in parallel. As these services are provided, a simultaneous need arises to know the combined limit of the inverter for those services. In the present paper, operational limits are addressed based on a utility scale for a real inverter scenario with an energy storage system (ESS) (1.5 MW). The paper begins by explaining how active and reactive power limits are calculated, illustrating the PQ maps depending on the converter rated current and voltage. Then, the effect of the negative sequence injection, the phase shift of compensated harmonics and the transformer de-rating are introduced step-by-step. Finally, inverter limits for active filter applications are summarized, to finally estimate active and reactive power limits along with the harmonic current injection for some example cases. The results show that while the phase shift of the injected negative sequence has a significant effect in the available inverter current, this is not the case for the phase shift of injected harmonics. However, the amplitude of the injected negative sequence and harmonics will directly impact the power capabilities of the inverter and therefore, depending on the grid-side voltage, it might be interesting to design an output transformer with a different de-rating factor to increase the power capabilities.

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37

Wang, Jianing, Yuan Fu, and Xiangyu Zhang. "Adaptive control of DFIG-based wind turbines for fault ride-through and reactive power support based on stator current transient component." Journal of Physics: Conference Series 2564, no. 1 (August 1, 2023): 012060. http://dx.doi.org/10.1088/1742-6596/2564/1/012060.

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Abstract The fault ride-through performance is improved through the control of the transient components of the stator current. The reactive power provided by the DFIG within the margin of the converter can significantly enhance the grid-connected safety of the DFIG. Firstly, the reasons for the fault overcurrent of the DFIG’s rotor are analyzed. Secondly, according to the operating conditions of the wind turbine, the reactive power support limit of the DFIG-based wind turbines based on the stator current transient component control is analyzed, and an adaptive reactive power support control suitable for fault ride-through is proposed to maximize its support potential for grid-connected voltage. Finally, the DFIG can not only suppress the rotor overcurrent through the transient component of the stator current but also have a reactive power support capability that is superior to the grid-connected standard.

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38

Hosseini Rostami, Seyyed Mohammad, Ahmad Jafari, Mohamadreza Darvish, and Mahdie Tari. "Optimal Reactive Power Allocation in Distribution Grid with Emphasis on Voltage Stability Using Particle Swarm Optimization Algorithm." Journal of Computational and Theoretical Nanoscience 18, no. 6 (June 1, 2021): 1737–43. http://dx.doi.org/10.1166/jctn.2021.9728.

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Анотація:

The structured environment requires an appropriate solution to reactive power management. During the restructuring of the electricity industry, power systems were divided into three main parts: generation, transmission, and distribution companies, coordinated by an independent system operator. Active power is the most important commodity traded in the electricity market. The independent operator of the grid has the duty of providing the necessary conditions for the realization of energy contracts on the transmission grid at any time. The arrangements that are considered for the production and delivery of energy to the consumer are called ancillary services. Among the various ancillary services required in a competitive market, reactive power services to control the bus voltage are among the most important services provided by the system operator. Lack of reactive power in the grid is one of the factors that limit the fulfillment of energy contracts and can even endanger the security and voltage stability in the grid. In references, by assuming the results of the active power market is constant, the optimal load of reactive power is distributed. This model always entitles the generator to receive cost for the reactive power needed to stabilize its active energy.

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39

Hosseini Rostami, Seyyed Mohammad, Ahmad Jafari, Mohamadreza Darvish, and Mahdie Tari. "Optimal Reactive Power Allocation in Distribution Grid with Emphasis on Voltage Stability Using Particle Swarm Optimization Algorithm." Journal of Computational and Theoretical Nanoscience 18, no. 6 (June 1, 2021): 1737–43. http://dx.doi.org/10.1166/jctn.2021.9728.

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Анотація:

The structured environment requires an appropriate solution to reactive power management. During the restructuring of the electricity industry, power systems were divided into three main parts: generation, transmission, and distribution companies, coordinated by an independent system operator. Active power is the most important commodity traded in the electricity market. The independent operator of the grid has the duty of providing the necessary conditions for the realization of energy contracts on the transmission grid at any time. The arrangements that are considered for the production and delivery of energy to the consumer are called ancillary services. Among the various ancillary services required in a competitive market, reactive power services to control the bus voltage are among the most important services provided by the system operator. Lack of reactive power in the grid is one of the factors that limit the fulfillment of energy contracts and can even endanger the security and voltage stability in the grid. In references, by assuming the results of the active power market is constant, the optimal load of reactive power is distributed. This model always entitles the generator to receive cost for the reactive power needed to stabilize its active energy.

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40

Zainuddin, Muammar, Frengki Eka Putra Surusa, Muhammad Asri, and Aprian Mokoagow. "Reactive power control of solar photovoltaic inverters for grid code compliance support." International Journal of Applied Power Engineering (IJAPE) 12, no. 3 (July 25, 2023): 300. http://dx.doi.org/10.11591/ijape.v12.i3.pp300-311.

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The compensation of reactive power in smart inverters is one solution to address the issue of voltage violations in the distribution network due to the penetration of solar photovoltaic power generation. However, options for reactive power control are limited during variations in irradiation and daily load on the feeder. This study aims to investigate the performance difference between four reactive power control techniques including Q(V) control, Q(P) control, fixed Q-Var, and fixed power factor (PF) available in smart inverters to reduce voltage violations due to PV integration and comply with the grid-code. Three-phase balanced power flow was simulated in a medium voltage distribution network (MVDN) considering the reactive power control mode of the inverter under variations in solar radiation and daily load. The results showed that the Q(V) control was more effective in improving distribution feeder voltage than other techniques and showed its compliance with the grid-code. The limiting setting point for var injection or power factor limit should be proportional to the daily grid load profile.

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41

Trinh, Chuong Trong. "VOLTAGE STABILITY INVESTIGATION OF GRID CONNECTED WIND FARM." Science and Technology Development Journal 12, no. 8 (April 28, 2009): 38–46. http://dx.doi.org/10.32508/stdj.v12i8.2273.

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At present, it is very common to find renewable energy resources, especially wind power, connected to distribution systems. The impact of this wind power on voltage distribution levels has been addressed in the literature. The majority of this works deals with the determination of the maximum active and reactive power that is possible to be connected on a system load bus, until the voltage at that bus reaches the voltage collapse point. It is done by the traditional methods of P-V curves reported in many references. Theoretical expression of maximum power limited by voltage stability transfer through a grid is formulated using an exact representation of distribution line with ABCD parameters. The expression is used to plot PV curves at various power factors of a radial system. Limited values of reactive power can be obtained. This paper presents a method to study the relationship between the active power and voltage (PV) at the load bus to identify the voltage stability limit. It is a foundation to build a permitted working operation region in complying with the voltage stability limit at the point of common coupling (PCC) connected wind farm.

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42

Wang, Xiaosheng, Ke Dai, Xinwen Chen, Xin Zhang, Qi Wu, and Ziwei Dai. "Reactive Power Compensation and Imbalance Suppression by Star-Connected Buck-Type D-CAP." Energies 12, no. 10 (May 18, 2019): 1914. http://dx.doi.org/10.3390/en12101914.

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Reactive power and negative-sequence current generated by inductive unbalanced load will not only increase line loss, but also cause the malfunction of relay protection devices triggered by a negative-sequence component in the power grid, which threatens the safe operation of the power system, so it is particularly important to compensate reactive power and suppress load imbalance. In this paper, reactive power compensation and imbalance suppression by a three-phase star-connected Buck-type dynamic capacitor (D-CAP) under an inductive unbalanced load are studied. Firstly, the relationship between power factor correction and imbalance suppression in a three-phase three-wire system is discussed, and the principle of D-CAP suppressing load imbalance is analyzed. Next, its compensation ability for negative-sequence currents is determined, which contains theoretical and actual compensation ability. Then an improved control strategy to compensate reactive power and suppress imbalance is proposed. If the load is slightly unbalanced, the D-CAP can completely compensate the reactive power and negative-sequence currents. If the load is heavily unbalanced, the D-CAP can only compensate the positive-sequence reactive power and a part of the negative-sequence currents due to the limit of compensation ability. Finally, a 33 kVar/220 V D-CAP prototype is built and experimental results verify the theoretical analysis and control strategy.

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43

Mark Ndubu, Nwohu. "Estimation of Bifurcation Point in Multi-Bus System Using Generator Reactive Power Limit Approach." International Journal of Electrical and Power Engineering 4, no. 2 (February 1, 2010): 154–59. http://dx.doi.org/10.3923/ijepe.2010.154.159.

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44

Gupta, Neeraj, Vinay Pant, and Biswarup Das. "Probabilistic load flow incorporating generator reactive power limit violations with spline based reconstruction method." Electric Power Systems Research 106 (January 2014): 203–13. http://dx.doi.org/10.1016/j.epsr.2013.08.011.

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45

Zhang, Yue Qiang, Yong Qiang Zhu, and Yan Zhang Liu. "Studies on Power Distribution of AC and VSC-HVDC Hybrid System for Wind Power Integration." Advanced Materials Research 676 (March 2013): 204–8. http://dx.doi.org/10.4028/www.scientific.net/amr.676.204.

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In order to study the power distribution strategy of AC and VSC-HVDC hybrid system for wind power integration, a strategy based on improving the transmission capacity of AC lines and reducing the power loss is proposed. By use of the decouple control of active and reactive power of the VSC-HVDC, the transmission capacity of the AC lines can be improved by absorbing enough reactive power, AC lines have the priority before they have reached their transmission limit, meanwhile the VSC-HVDC acts as STATCOM. When the AC lines have been fully used, the VSC-HVDC will act as STATCOM as well as transmit the rest power. A DFIG wind power integration system is set up by use of PSCAD/EMTDC, the simulation results show that the power distribution strategy can realize the wind power integration successfully and reduce the power loss, it can regard as a good method for wind power integration.

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46

Maklakov, Aleksandr S., Aleksandr A. Nikolaev, and Tatyana A. Lisovskaya. "Control over Grid Reactive Power by Using a Powerful Regenerative Controlled-Speed Synchronous Motor Drive." Designs 7, no. 3 (May 8, 2023): 62. http://dx.doi.org/10.3390/designs7030062.

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The authors propose a technique for reactive power compensation using a powerful regenerative controlled-speed synchronous motor drive (SMD) based on a three-level (3L) neutral point clamped (NPC) active front-end rectifier (AFE) and a voltage source inverter (VSI). The review of technical solutions for reactive power compensation showed that the limitations on the transmitted reactive power in the system under consideration still have not been studied. The paper provides a mathematical description and proposes synthesis-friendly block diagrams of the mathematical 3L-NPC-AFE-VSI and SMD models. The developed models allow defining the instantaneous values of the total 3L-NPC-AFE power consumed from the grid depending on the SMD load diagram. It is noted that the 3L-NPC-AFE-VSI-SMD system is designed without considering the opportunities for reactive power generation. It was determined that the limit value of reactive power generated by a 3L-NPC-AFE depends on the DC link voltage, the grid current consumption and the modulation index. The possibility of reactive power compensation by the SMD system through a 3L-NPC-AFE was experimentally tested on the main drive of a metal plate hot rolling mill. The analysis of the results obtained showed that during the breakdown, an SMD can generate reactive power equal to 16% of the total rated power using a 3L-NPC-AFE at a rated DC link voltage and without overcurrent. It was shown that generating reactive power is expedient in low-load SMD operation modes or at idle. Research in this area is promising due to the widespread use of high-power SMD based on a 3L-NPC-AFE-VSI and the tightening of requirements for energy saving and efficiency and supply voltage quality. The proposed reactive power control technique can be used as part of an industrial smart grid.

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47

Ma, Jinhui, Haifeng Ye, Zhi Li, Pingping Han, Zihao Lin, and Jianxiong Shi. "Research on Source-Network Coordination Voltage Control Strategy of Photovoltaic Power Plant Considering the Stability of Inverter Port Voltage." E3S Web of Conferences 143 (2020): 02018. http://dx.doi.org/10.1051/e3sconf/202014302018.

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Анотація:

At present, the reactive power distribution method considering the reactive power adjustment capacity of the inverter in the photovoltaic (PV) power plant will lead to the output voltage of the inverter exceeding the limit. In particular, the PV inverter adopts the constant reactive power control to support the voltage at point of common coupling (PCC), which has a good effect in the steady-state operation. However, when the system is subject to transient disturbance, the PV inverter cannot flexibly support the voltage level of the system by changing the reactive power output. Therefore, this paper proposes a source-network coordination control strategy aiming at the stability of bus voltage at PCC and inverter port voltage. Firstly, the paper introduced the advantages of constant voltage control of PV inverter. Then, the voltage and reactive power control objectives of the PV Inverter in the PV power plant were calculated by considering the PCC voltage, tie lines, power collection lines, the power of transformers and the voltage loss to realize the voltage and reactive power balance control between the inverters. Finally, an actual PV power plant simulation model was built to analyse the PCC voltage under the two conditions of PV output fluctuation and system fault to verify the effectiveness of the control strategy proposed in this paper. The proposed strategy has engineering application value for the realization of closed-loop voltage control between the power grid and PV power plant and the improvement of the active response ability to the PCC voltage.

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48

Махошев, А. А., О. А. Гаврина, and Р. В. Клюев. "Reactive Power Compensation in Thermal Ore Production." Вестник КРАУНЦ. Физико-математические науки, no. 2 (July 8, 2023): 126–40. http://dx.doi.org/10.26117/2079-6641-2023-43-2-126-140.

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Анотація:

В работе рассматриваются вопросы компенсации реактивной мощности при работе дуговых сталеплавильных печей (ДСП) при руднотермическом производстве. Приведены значения коэффициентов несинусоидальности напряжения для различных режимов плавки ДСП. Были осуществлены комплексные исследования, представляющие анализ эффективности снижения искажения напряжения силовыми фильтрами, которые могут быть представлены без динамической группы, и сравнение полученных данных с результатами использования фильтров 3-й и 5-й гармоник, входящих в состав компенсаторов реактивной мощности. Результаты исследований искажения формы кривой напряжения при работе ДСП свидетельствуют о том, что при отсутствии устройств динамической компенсации требования государственного стандарта по качеству электроэнергии обеспечиваются без включения фильтров. Фильтры необходимы для ограничения потребления при исключении возможности резонанса в параллельно включенных конденсаторах и индуктивных сопротивлениях связи с источником. По итогам выполненных расчетов видно, что установив фильтр 3-ей гармоники на шинах ЗРУ-35 кВ достигнуты существенные результаты, а именно обеспечена минимизация размахов напряжения (до 0,78%) и одновременно решен вопрос компенсации реактивной мощности (cosφ = 0,95) при минимальных удельных затратах. The paper deals with the issues of reactive power compensation during the operation of arc steelsmelting furnaces (EAF) in ore-thermal production. The values of voltage non-sinusoidality coefficients for various EAF melting modes are given. Comprehensive studies were carried out, presenting an analysis of the effectiveness of reducing voltage distortion by power filters, which can be presented without a dynamic group, and comparing the data obtained with the results of using filters of the 3rd and 5th harmonics, which are part of reactive power compensators. The results of studies of the distortion of the shape of the voltage curve during the operation of the EAF indicate that in the absence of dynamic compensation devices, the requirements of the state standard for the quality of electricity are provided without turning on filters. Filters are needed to limit consumption while eliminating the possibility of resonance in parallelconnected capacitors and source-coupled inductive reactances. According to the results of the performed calculations, it can be seen that by installing the 3rd harmonic filter on the ZRU-35 kV buses, significant results were achieved, namely, the voltage swings were minimized (up to 0.78%) and the issue of reactive power compensation was simultaneously resolved (cosφ = 0.95) at the lowest unit cost.

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49

Shende, Divya, Prashant Jagtap, and Rutuja Hiware. "Enhanced power quality using unified power flow controller systems." Journal of Physics: Conference Series 2089, no. 1 (November 1, 2021): 012035. http://dx.doi.org/10.1088/1742-6596/2089/1/012035.

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Abstract Electrical system frequently finds and issue due to unstable nature and power quality because of, in relation to great number of nonlinear charges. So, there is need to limit inside of these difficulties and produce fine voltage quality concerns. The Flexible Alternate Flow Transmission Systems (FACTS) are the framework made out of static gear works for the AC transmission of electrical energy. Unified_Power_Flow Controls (UPFC) are the excellent FACTS tools to attach series and shunt together and it could use for framing Power transmission sensitive and active power. Here in the paper, Unified Power Flow Control (UPFC) used to clear the voltage sink and Surge. Unified Control was developed and engineered using amplifiers and rectifiers. The real and reactive modifications in congruous control orientations at the receiver side. Use of Simulink of MATLAB checks quality of energy in the use of Unified Control.

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50

Sheng, Hao, Hsiao-Dong Chiang, and Yan-Feng Jiang. "Local Bifurcations of Electric Distribution Networks with Renewable Energy." International Journal of Bifurcation and Chaos 24, no. 07 (July 2014): 1450102. http://dx.doi.org/10.1142/s0218127414501028.

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Recent years have witnessed a growing trend towards the development and deployment of distributed generation (DG). It is shown that electric distribution networks with DGs can encounter two types of local bifurcations: saddle-node bifurcation and structure-induced bifurcation. The structure-induced bifurcation occurs when a transition between two structures of the distribution network takes place due to limited amount of reactive power supports from renewable energies. The saddle-node bifurcation occurs when the underlying distribution network reaches the limit of its delivery capability. The consequence of structure-induced bifurcation is an immediate instability induced by reactive power limits of renewable energy. It is numerically shown that both types of local bifurcations can occur at both small distribution networks and large-scale distribution networks with DGs. Physical explanations of these two local bifurcations are provided. Studies of local bifurcations in distribution networks provide insights regarding how to design controls to enhance distribution networks with DGs.

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