To see the other types of publications on this topic, follow the link: POWER SYSTEM DISTRIBUTION.
Dissertations / Theses on the topic 'POWER SYSTEM DISTRIBUTION'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'POWER SYSTEM DISTRIBUTION.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Fletcher, Robert Henry. "Optimal distribution system horizon planning /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/6018.
Full text
2
Yu, Xuebei. "Distribution system reliability enhancement." Thesis, Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/41091.
Full textAbstract:
Practically all everyday life tasks from economic transactions to entertainment depend on the availability of electricity. Some customers have come to expect a higher level of power quality and availability from their electric utility. Federal and state standards are now mandated for power service quality and utilities may be penalized if the number of interruptions exceeds the mandated standards. In order to meet the requirement for safety, reliability and quality of supply in distribution system, adaptive relaying and optimal network reconfiguration are proposed. By optimizing the system to be better prepared to handle a fault, the end result will be that in the event of a fault, the minimum number of customers will be affected. Thus reliability will increase.
The main function of power system protection is to detect and remove the faulted parts as fast and as selectively as possible. The problem of coordinating protective relays in electric power systems consists of selecting suitable settings such that their fundamental protective function is met under the requirements of sensitivity, selectivity, reliability, and speed. In the proposed adaptive relaying approach, weather data will be incorporated as follows. By using real-time weather information, the potential area that might be affected by the severe weather will be determined. An algorithm is proposed for adaptive optimal relay setting (relays will optimally react to a potential fault). Different types of relays (and relay functions) and fuses will be considered in this optimization problem as well as their coordination with others. The proposed optimization method is based on mixed integer programming that will provide the optimal relay settings including pickup current, time dial setting, and different relay functions and so on.
The main function of optimal network reconfiguration is to maximize the power supply using existing breakers and switches in the system. The ability to quickly and flexibly reconfigure the power system of an interconnected network of feeders is a key component of Smart Grid. New technologies are being injected into the distribution systems such as advanced metering, distribution automation, distribution generation and distributed storage. With these new technologies, the optimal network reconfiguration becomes more complicated. The proposed algorithms will be implemented and demonstrated on a realistic test system. The end result will be improved reliability. The improvements will be quantified with reliability indexes such as SAIDI.
3
Rivas-Davalos, Francisco. "A genetic algorithm for power distribution system planning." Thesis, Brunel University, 2004. http://bura.brunel.ac.uk/handle/2438/7891.
Full textAbstract:
The planning of distribution systems consists in determining the optimum site and size of new substations and feeders in order to satisfy the future power demand with minimum investment and operational costs and an acceptable level of reliability. This problem is a combinatorial, non-linear and constrained optimization problem. Several solution methods based on genetic algorithms have been reported in the literature; however, some of these methods have been reported with applications to small systems while others have long solution time. In addition, the vast majority of the developed methods handle planning problems simplifying them as single-objective problems but, there are some planning aspects that can not be combined into a single scalar objective; therefore, they require to be treated separately. The cause of these shortcomings is the poor representation of the potential solutions and their genetic operators This thesis presents the design of a genetic algorithm using a direct representation technique and specialized genetic operators for power distribution system expansion planning problems. These operators effectively preserve and exploit critical configurations that contribute to the optimization of the objective function. The constraints of the problems are efficiently handle with new strategies. The genetic algorithm was tested on several theoretical and real large-scale power distribution systems. Problems of network reconfiguration for loss reduction were also included in order to show the potential of the algorithm to resolve operational problems. Both single-objective and multi-objective formulations were considered in the tests. The results were compared with results from other heuristic methods such as ant colony system algorithms, evolutionary programming, differential evolution and other genetic algorithms reported in the literature. From these comparisons it was concluded that the proposed genetic algorithm is suitable to resolve problems of largescale power distribution system planning. Moreover, the algorithm proved to be effective, efficient and robust with better performance than other previous methods.
4
Whitcomb, Clifford Alan. "Composite system analysis of advanced shipboard electrical power distribution systems." Thesis, Cambridge, Massachusetts : Massachusetts Institute of Technology, 1992. http://handle.dtic.mil/100.2/ADA254851.
Full textAbstract:
Thesis (Nav. E.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1992 and Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1992.Thesis Advisor: Kirtley, James L., Jr. "May 1992." Description based on title screen as viewed on March 30, 2009. Includes bibliographical references (p. 73-74). Also available in print.
5
Ibrahim, Sarmad Khaleel. "DISTRIBUTION SYSTEM OPTIMIZATION WITH INTEGRATED DISTRIBUTED GENERATION." UKnowledge, 2018. https://uknowledge.uky.edu/ece_etds/116.
Full textAbstract:
In this dissertation, several volt-var optimization methods have been proposed to improve the expected performance of the distribution system using distributed renewable energy sources and conventional volt-var control equipment: photovoltaic inverter reactive power control for chance-constrained distribution system performance optimisation, integrated distribution system optimization using a chance-constrained formulation, integrated control of distribution system equipment and distributed generation inverters, and coordination of PV inverters and voltage regulators considering generation correlation and voltage quality constraints for loss minimization. Distributed generation sources (DGs) have important benefits, including the use of renewable resources, increased customer participation, and decreased losses. However, as the penetration level of DGs increases, the technical challenges of integrating these resources into the power system increase as well. One such challenge is the rapid variation of voltages along distribution feeders in response to DG output fluctuations, and the traditional volt-var control equipment and inverter-based DG can be used to address this challenge.
These methods aim to achieve an optimal expected performance with respect to the figure of merit of interest to the distribution system operator while maintaining appropriate system voltage magnitudes and considering the uncertainty of DG power injections. The first method is used to optimize only the reactive power output of DGs to improve system performance (e.g., operating profit) and compensate for variations in active power injection while maintaining appropriate system voltage magnitudes and considering the uncertainty of DG power injections over the interval of interest. The second method proposes an integrated volt-var control based on a control action ahead of time to find the optimal voltage regulation tap settings and inverter reactive control parameters to improve the expected system performance (e.g., operating profit) while keeping the voltages across the system within specified ranges and considering the uncertainty of DG power injections over the interval of interest. In the third method, an integrated control strategy is formulated for the coordinated control of both distribution system equipment and inverter-based DG. This control strategy combines the use of inverter reactive power capability with the operation of voltage regulators to improve the expected value of the desired figure of merit (e.g., system losses) while maintaining appropriate system voltage magnitudes. The fourth method proposes a coordinated control strategy of voltage and reactive power control equipment to improve the expected system performance (e.g., system losses and voltage profiles) while considering the spatial correlation among the DGs and keeping voltage magnitudes within permissible limits, by formulating chance constraints on the voltage magnitude and considering the uncertainty of PV power injections over the interval of interest.
The proposed methods require infrequent communication with the distribution system operator and base their decisions on short-term forecasts (i.e., the first and second methods) and long-term forecasts (i.e., the third and fourth methods). The proposed methods achieve the best set of control actions for all voltage and reactive power control equipment to improve the expected value of the figure of merit proposed in this dissertation without violating any of the operating constraints. The proposed methods are validated using the IEEE 123-node radial distribution test feeder.
6
Javanshir, Marjan. "DC distribution system for data center." Thesis, Click to view the E-thesis via HKUTO, 2007. http://sunzi.lib.hku.hk/hkuto/record/B39344952.
Full text
7
Yu, Qiuli. "Multi-agent systems for reconfiguration of shipboard integrated power system including AC-DC zonal distribution system." Diss., Mississippi State : Mississippi State University, 2008. http://library.msstate.edu/etd/show.asp?etd=etd-11072008-122943.
Full text
8
Mahajan, Nikhil R. "System Protection for Power Electronic Building Block Based DC Distribution Systems." NCSU, 2004. http://www.lib.ncsu.edu/theses/available/etd-12052004-233822/.
Full textAbstract:
The purpose of this research has been to develop an agent based protection and reconfiguration scheme for power electronic building block based (PEBB) DC distribution systems. One of the foremost applications would be in the new zonal DC distribution on naval ships. The research involves the design of an agent based protection scheme which uses the PEBBs for current limiting and circuit breaking purposes. Considerations are given to reduce the system downtime under fault conditions, allow proper coordination and provide backup protection. The research also involves the design of a reconfiguration management scheme based on collaborative agents. The collaboration ensures that the reconfiguration is achieved at a global level, enhancing the system survivability under the conditions of multiple faults and damages. The coordination ensures that only the faulted part of the system is isolated and the reconfiguration makes sure that the power to the healthy part of the system is supplied continuously. The reconfiguration management also performs load shedding if the generation does not meet the load demand of the reconfigured system due to a fault or damage in the generator.
9
Janovsky, Pavel. "Large-scale coalition formation: application in power distribution systems." Diss., Kansas State University, 2017. http://hdl.handle.net/2097/35328.
Full textAbstract:
Doctor of PhilosophyDepartment of Computing and Information Sciences
Scott A. DeLoach
Coalition formation is a key cooperative behavior of a system of multiple autonomous agents. When the capabilities of individual agents are not su fficient for the improvement of well-being of the individual agents or of the entire system, the agents can bene t by joining forces together in coalitions. Coalition formation is a technique for finding coalitions that are best fi tted to achieve individual or group goals. This is a computationally expensive task because often all combinations of agents have to be considered in order to find the best assignments of agents to coalitions. Previous research has therefore focused mainly on small-scale or otherwise restricted systems. In this thesis we study coalition formation in large-scale multi-agent systems. We propose an approach for coalition formation based on multi-agent simulation. This approach allows us to find coalitions in systems with thousands of agents. It also lets us modify behaviors of individual agents in order to better match a specific coalition formation application. Finally, our approach can consider both social welfare of the multi-agent system and well-being of individual self-interested agents. Power distribution systems are used to deliver electric energy from the transmission system to households. Because of the increased availability of distributed generation using renewable resources, push towards higher use of renewable energy, and increasing use of electric vehicles, the power distribution systems are undergoing signi ficant changes towards active consumers who participate in both supply and demand sides of the electricity market and the underlying power grid. In this thesis we address the ongoing change in power distribution systems by studying how the use of renewable energy can be increased with the help of coalition formation. We propose an approach that lets renewable generators, which face uncertainty in generation prediction, to form coalitions with energy stores, which on the other hand are always able to deliver the committed power. These coalitions help decrease the uncertainty of the power generation of renewable generators, consequently allowing the generators to increase their use of renewable energy while at the same time increasing their pro fits. Energy stores also bene t from participating in coalitions with renewable generators, because they receive payments from the generators for the availability of their power at speci fic time slots. We first study this problem assuming no physical constraints of the underlying power grid. Then we analyze how coalition formation of renewable generators and energy stores in a power grid with physical constraints impacts the state of the grid, and we propose agent behavior that leads to increase in use of renewable energy as well as maintains stability of the grid.
10
Cartier, J. C. "Power quality analysis in a CC-130 Hercules aircraft power distribution system." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0001/MQ44836.pdf.
Full text
11
Cintuglu, Mehmet Hazar. "Wide-Area Time-Synchronized Closed-Loop Control of Power Systems And Decentralized Active Distribution Networks." FIU Digital Commons, 2016. http://digitalcommons.fiu.edu/etd/3031.
Full textAbstract:
The rapidly expanding power system grid infrastructure and the need to reduce the occurrence of major blackouts and prevention or hardening of systems against cyber-attacks, have led to increased interest in the improved resilience of the electrical grid. Distributed and decentralized control have been widely applied to computer science research. However, for power system applications, the real-time application of decentralized and distributed control algorithms introduce several challenges. In this dissertation, new algorithms and methods for decentralized control, protection and energy management of Wide Area Monitoring, Protection and Control (WAMPAC) and the Active Distribution Network (ADN) are developed to improve the resiliency of the power system. To evaluate the findings of this dissertation, a laboratory-scale integrated Wide WAMPAC and ADN control platform was designed and implemented. The developed platform consists of phasor measurement units (PMU), intelligent electronic devices (IED) and programmable logic controllers (PLC). On top of the designed hardware control platform, a multi-agent cyber-physical interoperability viii framework was developed for real-time verification of the developed decentralized and distributed algorithms using local wireless and Internet-based cloud communication. A novel real-time multiagent system interoperability testbed was developed to enable utility independent private microgrids standardized interoperability framework and define behavioral models for expandability and plug-and-play operation. The state-of-theart power system multiagent framework is improved by providing specific attributes and a deliberative behavior modeling capability. The proposed multi-agent framework is validated in a laboratory based testbed involving developed intelligent electronic device prototypes and actual microgrid setups. Experimental results are demonstrated for both decentralized and distributed control approaches. A new adaptive real-time protection and remedial action scheme (RAS) method using agent-based distributed communication was developed for autonomous hybrid AC/DC microgrids to increase resiliency and continuous operability after fault conditions. Unlike the conventional consecutive time delay-based overcurrent protection schemes, the developed technique defines a selectivity mechanism considering the RAS of the microgrid after fault instant based on feeder characteristics and the location of the IEDs. The experimental results showed a significant improvement in terms of resiliency of microgrids through protection using agent-based distributed communication.
12
Duvnjak, Zarkovic Sanja. "Security of Electricity Supply in Power Distribution System : Optimization Algorithms for Reliability Centered Distribution System Planning." Licentiate thesis, KTH, Elektroteknisk teori och konstruktion, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-281813.
Full textAbstract:
The importance of electricity in everyday life and demands to improve the reliability of distribution systems force utilities to operate and plan their networks in a more secure and economical manner. With higher demands on reliability from both customers and regulators, a big pressure has been put on the security of electricity supply which is considered as a fundamental requirement for modern societies. Thus, efficient solutions for reliability and security of supply improvements are not just of increasing interest, but also have significant socio-economic relevance. Distribution system planning (DSP) is one of the major activities of distribution utilities to deal with reliability enhancement. This thesis deals with developing optimization algorithms, which aim is to min- imize customer interruption costs, and thus maximize the reliability of the system. This is implemented either by decreasing customer interruption duration, frequency of customer interruptions or both. The algorithms are applied on a single or multi- ple DSP problems. Mixed-integer programming has been used as an optimization approach. It has been shown that solving and optimizing each one of the DSP problems contributes greatly to the reliability improvement, but brings certain challenges. Moreover, applying algorithms on multiple and integrated DSP problems together leads to even bigger complexity and burdensome. However, going toward this inte- grated approach results in a more appropriate and realistic DSP model. The idea behind the optimization is to achieve balance between reliability and the means to achieve this reliability. It is a decision making process, i.e. a trade-off between physical and pricing dimension of security of supply.QC 20200925
13
McDermott, Thomas E. "A Heuristic Nonlinear Constructive Method for Electric Power Distribution System Reconfiguration." Diss., Virginia Tech, 1998. http://hdl.handle.net/10919/30447.
Full textAbstract:
The electric power distribution system usually operates a radial configuration, with tie switches between circuits to provide alternate feeds. The losses would be minimized if all switches were closed, but this is not done because it complicates the system's protection against overcurrents. Whenever a component fails, some of the switches must be operated to restore power to as many customers as possible. As loads vary with time, switch operations may reduce losses in the system. Both of these are applications for reconfiguration.
The problem is combinatorial, which precludes algorithms that guarantee a global optimum. Most existing reconfiguration algorithms fall into two categories. In the first, branch exchange, the system operates in a feasible radial configuration and the algorithm opens and closes candidate switches in pairs. In the second, loop cutting, the system is completely meshed and the algorithm opens candidate switches to reach a feasible radial configuration. Reconfiguration algorithms based on linearized transshipment, neural networks, heuristics, genetic algorithms, and simulated annealing have also been reported, but not widely used. These existing reconfiguration algorithms work with a simplified model of the power system, and they handle voltage and current constraints approximately, if at all.
The algorithm described here is a constructive method, using a full nonlinear power system model that accurately handles constraints. The system starts with all switches open and all failed components isolated. An optional network power flow provides a lower bound on the losses. Then the algorithm closes one switch at a time to minimize the increase in a merit figure, which is the real loss divided by the apparent load served. The merit figure increases with each switch closing. This principle, called discrete ascent optimal programming (DAOP), has been applied to other power system problems, including economic dispatch and phase balancing. For reconfiguration, the DAOP method's greedy nature is mitigated with a backtracking algorithm. Approximate screening formulas have also been developed for efficient use with partial load flow solutions. This method's main advantage is the accurate treatment of voltage and current constraints, including the effect of control action. One example taken from the literature shows how the DAOP-based algorithm can reach an optimal solution, while adjusting line voltage regulators to satisfy the voltage constraints.Ph. D.
14
Chen, Linwei. "Distribution network supports for transmission system reactive power management." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/distribution-network-supports-for-transmission-system-reactive-power-management(abcc8197-fd85-478b-b91a-fd3d0b3220db).html.
Full textAbstract:
To mitigate high voltages in transmission systems with low demands, traditional solutions often consider the installation of reactive power compensators. The deployment and tuning of numbers of VAr compensators at various locations may not be cost-effective. This thesis presents an alternative method that utilises existing parallel transformers in distribution networks to provide reactive power supports for transmission systems under low demands. The operation of parallel transformers in small different tap positions, i.e. with staggered taps, can provide a means of absorbing reactive power. The aggregated reactive power absorption from many pairs of parallel transformers could be sufficient to provide voltage support to the upstream transmission network. Network capability studies have been carried out to investigate the reactive power absorption capability through the use of tap stagger. The studies are based on a real UK High Voltage distribution network, and the tap staggering technique has been applied to primary substation transformers. The results confirm that the tap staggering method has the potential to increase the reactive power demand drawn from the transmission grid. This thesis also presents an optimal control method for tap stagger to minimise the introduced network loss as well as the number of tap switching operations involved. A genetic algorithm (GA) based procedure has been developed to solve the optimisation problem. The GA method has been compared with two alternative solution approaches, i.e. the rule-based control scheme and the branch-and-bound algorithm. The results indicate that the GA method is superior to the other two approaches. The economic and technical impacts of the tap staggering technique on the transmission system has been studied. In the economic analysis, the associated costs of applying the tap staggering method have been investigated from the perspective of transmission system operator. The IEEE Reliability Test System has been used to carry out the studies, and the results have been compared with the installation of shunt reactors. In the technical studies, the dynamic impacts of tap staggering or reactor switching on transmission system voltages have been analysed. From the results, the tap staggering technique has more economic advantages than reactors and can reduce voltage damping as well as overshoots during the transient states.
15
Dorji, Tempa. "Reliability Assessment of Distribution Systems : -Including a case study on Wangdue Distribution System in Bhutan." Thesis, Norwegian University of Science and Technology, Department of Electrical Power Engineering, 2009. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-9828.
Full textAbstract:
A stable and reliable electric power supply system is an inevitable pre-requisite for the technological and economic growth of any nation. Due to this, utilities must strive and ensure that the customers reliability requirements are met and the regulators requirements satisfied at the lowest possible cost. It is known fact around the world that 90% of the of the customer service interruptions are caused due to failure in distribution system. Therefore, it is worth considering reliability worth assessments as it provides an opportunity to incorporate the cost or losses incurred by the utilities customer as a result of power failure and this must be considered in planning and operating practices. The system modeling and simulation study is carried out on one of the districts distribution system which consists of 33kV and 11kV network in Bhutan. The reliability assessment is done on both 11 and 33kV system to assess the performance of the present system and also predictive reliability analysis for the future system considering load growth and system expansion. The alternative which gives low SAIDI, SAIFI and minimum breakeven costs are being assessed and considered. The reliability of 33kV system could be further improved by installation of load break switch, auto recloser and connecting with line coming from other district (reserve) at reasonable break even cost. The decision base could be further improved by having Bhutans context interruption cost. However, the questionnaires which may be used in Bhutan to acquire interruption costs from the customers are being proposed. The utility should have their own reliability improvement strategy depending upon their needs and requirements of the regulators. Although there is no magic bullet in managing power quality issues, utilities can maximize network performance and better serve customers by diligently addressing trouble prone areas. In order to achieve this objective, a computer program NetBas/Lesvik is used to run load flow and reliability analysis, thus selecting the alternatives either based on reliability indices or on cost benefit ratio.
16
Manghat, Jaidev. "Simulation of power distribution management system using OMACS metamodel." Manhattan, Kan. : Kansas State University, 2008. http://hdl.handle.net/2097/944.
Full text
17
Weinstein, Lee. "Scale free networks and their power law distribution." Diss., Connect to the thesis, 2005. http://hdl.handle.net/10066/3880.
Full text
18
Ozel, Kerem. "Losses In Electric Distribution System." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/2/12607916/index.pdf.
Full textAbstract:
The purpose of this thesis is to examine the technical losses in Electric Distribution Systems, the sources of the losses, minimum levels of the losses, ways to decrease the losses and current applications in Turkey. The wrong and weak parts of the current applications are determined and emphasized. Ways to decrease losses in Distribution Systems are advised.
The energy resources in the world are decreasing rapidly. There is a rapid growth in consumption. It is a must to use existing resources in most efficient way because there is no unlimited energy source. Losses in the electric distribution systems are one of the most important subjects because the most of the technical losses in electric systems occur in the distribution systems.
19
Thandi, Gurjit Singh. "Modeling, Control and Stability Analysis of a PEBB Based DC Distribution Power System." Thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/36788.
Full textAbstract:
Power Electronic Building Block (PEBB) concept is to provide generic building blocks for power conversion, regulation and distribution with control intelligence and autonomy. A comprehensive modeling and analysis of a PEBB based DC distributed power system (DPS), comprising of a front end power factor correction (PFC) boost rectifier, a DC-DC converter and a three phase four leg inverter is performed. All the sub-systems of the DC DPS are modeled and analyzed for stability and good transient performance.
A comprehensive stability analysis of a PEBB based DC DPS is performed. The effect of impedance overlap on the system and individual sub-systems is examined. Ability of a PEBB based converter to stabilize the integrated system by actively changing the system bandwidth is presented. The fault tolerance capability in a PEBB based rectifier is established by ensuring stable system operation, with one leg of the rectifier failed open-circuited.
Master of Science
20
Mao, Yiming Mui Karen. "Protection system design for power distribution systems in the presence of distributed generation /." Philadelphia, Pa. : Drexel University, 2005. http://dspace.library.drexel.edu/handle/1860/501.
Full text
21
Weerasinghe, Handuwala Dewage Dulan Jayanatha. "Planning optimal load distribution and maximum renewable energy from wind power on a radial distribution system." Diss., Kansas State University, 2015. http://hdl.handle.net/2097/28714.
Full textAbstract:
Doctor of PhilosophyElectrical and Computer Engineering
Ruth D. Miller
Optimizing renewable distributed generation in distribution systems has gained popularity with changes in federal energy policies. Various studies have been reported in this regard and most of the studies are based on optimum wind and/or solar generation planning in distribution system using various optimization techniques such as analytical, numerical, and heuristic. However, characteristics such as high energy density, relatively lower footprint of land, availability, and local reactive power compensation ability, have gained increased popularity for optimizing distributed wind generation (DWG) in distribution systems. This research investigated optimum distributed generation planning (ODGP) using two primary optimization techniques: analytical and heuristic. In first part of the research, an analytical optimization method called “Combined Electrical Topology (CET)” was proposed in order to minimize the impact of intentional structural changes in distribution system topology, in distributed generation/ DWG placement. Even though it is still rare, DWG could be maximized to supply base power demand of three-phase unbalanced radial distribution system, combined with distributed battery energy storage systems (BESS). In second part of this research the usage of DWG/BESS as base power generation, and to extend the ability to sustain the system in a power grid failure for a maximum of 1.5 hours was studied. IEEE 37-node, three-phase unbalanced radial distribution system was used as the test system to optimize wind turbines and sodium sulfide (NaS) battery units with respect to network real power losses, system voltage profile, DWG/BESS availability and present value of cost savings. In addition, DWG’s ability to supply local reactive power in distribution system was also investigated. Model results suggested that DWG/NaS could supply base power demand of a threephase unbalanced radial distribution system. In addition, DWG/NaS were able to sustain power demand of a three-phase unbalanced distribution system for 1.5 hours in the event of a power grid failure.
22
Fallier, William F. "Analysis of system wide distortion in an integrated power system utilizing a high voltage DC bus and silicon carbide power devices." Thesis, Monterey, California. Naval Postgraduate School, 2007. http://hdl.handle.net/10945/3006.
Full textAbstract:
This research investigates the distortion on the electrical distribution system for a high voltage DC Integrated Power System (IPS). The analysis was concentrated on the power supplied to a propulsion motor driven by an inverter with simulated silicon carbide switches. Theoretically, silicon carbide switches have the advantage of being able to withstand a very large blocking voltage and carry very large forward currents. Silicon carbide switches are also very efficient due to their quick rise and fall times. Since silicon carbide switches can withstand high voltage differentials and switch faster than silicon switches, the switching effects on the electrical distribution system were investigated. The current state of silicon carbide power electronics was also investigated. This research quantifies the current and voltage distortion over various operating conditions. A system model was developed using Matlab, Simulink, and SimPowerSystems. The model consisted of a synchronous generator supplying a rectifier and inverter set driving an induction motor. This induction motor simulates the propulsion motor for a Navy ship. This model had a DC link voltage of 10 kV in order to simulate future Navy IPS systems. The current and voltage distortion were compared to MIL STD 1399 and IEEE STD 519 and 45.Contract Number: N62271-97-G-0026
23
Arunachalam, Suresh. "Expansion of an existing power system - a study." Diss., Rolla, Mo. : University of Missouri--Rolla, 1989. http://scholarsmine.mst.edu/thesis/pdf/Arunachalam_09007dcc805881ce.pdf.
Full textAbstract:
Thesis (M.S.)--University of Missouri--Rolla, 1989.Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed October 7, 2008) Includes bibliographical references (p. 89).
24
Ratanapanachote, Somnida. "Applications of an electronic transformer in a power distribution system." Texas A&M University, 2004. http://hdl.handle.net/1969.1/2756.
Full textAbstract:
In electrical power distribution and power electronic applications, a transformer is an indispensable component which performs many functions. At its operating frequency (60/50 Hz), it is one of the most bulky and expensive components. The concept of the electronic transformer introduced previously has shown considerable reduction in size, weight, and volume by operating at a higher frequency.
In this dissertation, the concept of the electronic transformer is further extended to the auto-connected phase-shifting type to reduce harmonics generated by nonlinear loads. It is shown that with the addition of primary side and secondary side AC/AC converters achieves phase-shifting. With the addition of converters, magnetic components are operated at a higher frequency to yield a smaller size and weight. Two types of auto-connected electronic transformer configurations are explored. In the first configuration, the secondary converter is eliminated and the output is suitable for rectifier type loads such as adjustable speed drives. In the second configuration, the
secondary converter is added to obtain a sinusoidal phase-shifted AC output voltage. This approach is applicable in general applications. With the proposed approaches, the th and 7th harmonic in utility line currents, generated by two sets of nonlinear loads, are subtracted within the electronic transformer, thereby reducing the total harmonic distortion (THD) of the line current. The analysis and simulation results are presented.
In the second part of the dissertation, the electronic transformer concept is applied to a telecommunication power supply (-48 VDC) system. The proposed approach consists of a matrix converter to convert the low frequency three-phase input AC utility to a high frequency AC output without a DC-link. The output of the matrix converter is then processed via a high frequency isolation transformer to produce -48 VDC. Digital control of the system ensures that the output voltage is regulated and the input currents are of high quality, devoid of low frequency harmonics and at near unity input power factor under varying load conditions. Due to the absence of DC-link electrolytic capacitors, the power density of the proposed rectifier is shown to be higher. Analysis, design example and experimental results are presented from a three-phase 208 V, 1.5 kW laboratory prototype converter.
25
Guo, Wennan. "An ac-ac inverter for high frequency power distribution system." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ59305.pdf.
Full text
26
Smith, Philip Hartley. "Electrical Distribution Modeling:An Integration of Engineering Analysis and Geographic Information Systems." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/36158.
Full textAbstract:
This thesis demonstrates the value of integrating electrical distribution engineering analysis with Geographic Information Systems (GIS). The 37-Node IEEE Feeder model was used as the base distribution system in this study. It was modeled separately, both in software capable of unbalanced load-flow and in an industry-standard GIS environment. Both tools utilized were commercially available, off-the shelf products indicative of those used in academia and in basic GIS installations. The foundational data necessary to build these models is representative of information required by a variety of utility departments for a multitude of applications. It is inherent to most systems within an enterprise-level, business-wide data model and therefore can be used to support a variety of applications. In this instance, infrastructure information is assumed to be managed and housed with the GIS. This data provides the required information as input for load-flow calculations. The engineering analysis is performed within DistributionSystem 4.01 and its output is passed back to the GIS in tabular format for incorporation. This thesis investigates the transfer of information between GIS and DistributionSystem 4.01 and demonstrates the extended display capabilities in the GIS environment. This research is implemented on a small scale, but is intended to highlight the need for standardization and automatic integration of these systems as well as others that are fundamental to the effective management of electrical distribution systems.Master of Science
27
Youssef, Tarek. "Co-design of Security Aware Power System Distribution Architecture as Cyber Physical System." FIU Digital Commons, 2017. http://digitalcommons.fiu.edu/etd/3210.
Full textAbstract:
The modern smart grid would involve deep integration between measurement nodes, communication systems, artificial intelligence, power electronics and distributed resources. On one hand, this type of integration can dramatically improve the grid performance and efficiency, but on the other, it can also introduce new types of vulnerabilities to the grid. To obtain the best performance, while minimizing the risk of vulnerabilities, the physical power system must be designed as a security aware system.
In this dissertation, an interoperability and communication framework for microgrid control and Cyber Physical system enhancements is designed and implemented taking into account cyber and physical security aspects. The proposed data-centric interoperability layer provides a common data bus and a resilient control network for seamless integration of distributed energy resources. In addition, a synchronized measurement network and advanced metering infrastructure were developed to provide real-time monitoring for active distribution networks.
A hybrid hardware/software testbed environment was developed to represent the smart grid as a cyber-physical system through hardware and software in the loop simulation methods. In addition it provides a flexible interface for remote integration and experimentation of attack scenarios.
The work in this dissertation utilizes communication technologies to enhance the performance of the DC microgrids and distribution networks by extending the application of the GPS synchronization to the DC Networks. GPS synchronization allows the operation of distributed DC-DC converters as an interleaved converters system. Along with the GPS synchronization, carrier extraction synchronization technique was developed to improve the system’s security and reliability in the case of GPS signal spoofing or jamming.
To improve the integration of the microgrid with the utility system, new synchronization and islanding detection algorithms were developed. The developed algorithms overcome the problem of SCADA and PMU based islanding detection methods such as communication failure and frequency stability. In addition, a real-time energy management system with online optimization was developed to manage the energy resources within the microgrid. The security and privacy were also addressed in both the cyber and physical levels. For the physical design, two techniques were developed to address the physical privacy issues by changing the current and electromagnetic signature. For the cyber level, a security mechanism for IEC 61850 GOOSE messages was developed to address the security shortcomings in the standard.
28
Anderson, Sharon Lee. "Reduced order power system models for transient stability studies." Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-09052009-040743/.
Full text
29
Khaliq, Abdul. "Preventive control for the attainment of a dynamically secure power system." Diss., Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/13893.
Full text
30
Thompson, Jeffrey Craig. "An expert system for protection system design of interconnected electrical distribution circuits." Diss., This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-06062008-170345/.
Full text
31
Campbell, Angela Mari. "Architecting aircraft power distribution systems via redundancy allocation." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53087.
Full textAbstract:
Recently, the environmental impact of aircraft and rising fuel prices have become an increasing concern in the aviation industry. To address these problems, organizations such as NASA have set demanding goals for reducing aircraft emissions, fuel burn, and noise. In an effort to reach the goals, a movement toward more-electric aircraft and electric propulsion has emerged. With this movement, the number of critical electrical loads on an aircraft is increasing causing power system reliability to be a point of concern.
Currently, power system reliability is maintained through the use of back-up power supplies such as batteries and ram-air-turbines (RATs). However, the increasing power requirements for critical loads will quickly outgrow the capacity of the emergency devices. Therefore, reliability needs to be addressed when designing the primary power distribution system.
Power system reliability is a function of component reliability and redundancy. Component reliability is often not determined until detailed component design has occurred; however, the amount of redundancy in the system is often set during the system architecting phase. In order to meet the capacity and reliability requirements of future power distribution systems, a method for redundancy allocation during the system architecting phase is needed.
This thesis presents an aircraft power system design methodology that is based upon the engineering decision process. The methodology provides a redundancy allocation strategy and quantitative trade-off environment to compare architecture and technology combinations based upon system capacity, weight, and reliability criteria.
The methodology is demonstrated by architecting the power distribution system of an aircraft using turboelectric propulsion. The first step in the process is determining the design criteria which includes a 40 MW capacity requirement, a 20 MW capacity requirement for the an engine-out scenario, and a maximum catastrophic failure rate of one failure per billion flight hours. The next step is determining gaps between the performance of current power distribution systems and the requirements of the turboelectric system. A baseline architecture is analyzed by sizing the system using the turboelectric system power requirements and by calculating reliability using a stochastic flow network. To overcome the deficiencies discovered, new technologies and architectures are considered. Global optimization methods are used to find technology and architecture combinations that meet the system objectives and requirements. Lastly, a dynamic modeling environment is constructed to study the performance and stability of the candidate architectures. The combination of the optimization process and dynamic modeling facilitates the selection of a power system architecture that meets the system requirements and objectives.
32
Wang, Zhuding. "Distribution system planning a set of new formulations and hybrid algorithms /." online access from Digital Dissertation Consortium access full-text, 2000. http://libweb.cityu.edu.hk/cgi-bin/er/db/ddcdiss.pl?9994047.
Full text
33
Scott, Nigel Clive. "Limitation of distribution system voltage by decentralised load control." Thesis, University of Newcastle Upon Tyne, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327325.
Full text
34
Fang, Yong Jie. "Dynamic and transient system control using fast acting quadrature boosters." Thesis, Imperial College London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244084.
Full text
35
Singh, Manish K. "Optimal Operation of Water and Power Distribution Networks." Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/86860.
Full textAbstract:
Under the envisioned smart city paradigm, there is an increasing demand for the coordinated operation of our infrastructure networks. In this context, this thesis puts forth a comprehensive toolbox for the optimization of electric power and water distribution networks. On the analytical front, the toolbox consists of novel mixed-integer (non)-linear program (MINLP) formulations; convex relaxations with optimality guarantees; and the powerful technique of McCormick linearization. On the application side, the developed tools support the operation of each of the infrastructure networks independently, but also towards their joint operation. Starting with water distribution networks, the main difficulty in solving any (optimal-) water flow problem stems from a piecewise quadratic pressure drop law. To efficiently handle these constraints, we have first formulated a novel MINLP, and then proposed a relaxation of the pressure drop constraints to yield a mixed-integer second-order cone program. Further, a novel penalty term is appended to the cost that guarantees optimality and exactness under pre-defined network conditions. This contribution can be used to solve the WF problem; the OWF task of minimizing the pumping cost satisfying operational constraints; and the task of scheduling the operation of tanks to maximize the water service time in an area experiencing electric power outage. Regarding electric power systems, a novel MILP formulation for distribution restoration using binary indicator vectors on graph properties alongside exact McCormick linearization is proposed. This can be used to minimize the restoration time of an electric system under critical operational constraints, and to enable a coordinated response with the water utilities during outages.Master of Science
The advent of smart cities has promoted research towards interdependent operation of utilities such as water and power systems. While power system analysis is significantly developed due to decades of focused research, water networks have been relying on relatively less sophisticated tools. In this context, this thesis develops Advanced efficient computational tools for the analysis and optimization for water distribution networks. Given the consumer demands, an optimal water flow (OWF) problem for minimizing the pump operation cost is formulated. Developing a rigorous analytical framework, the proposed formulation provides significant computational improvements without compromising on the accuracy. Explicit network conditions are provided that guarantee the optimality and feasibility of the obtained OWF solution. The developed formulation is next used to solve two practical problems: the water flow problem, that solves the complex physical equations yielding nodal pressures and pipeline flows given the demands/injections; and an OWF problem that finds the best operational strategy for water utilities during power outages. The latter helps the water utility to maximize their service time during power outages, and helps power utilities better plan their restoration strategy. While the increased instrumentation and automation has enabled power utilities to better manage restoration during outages, finding an optimal strategy remains a difficult problem. The operational and coordination requirements for the upcoming distributed resources and microgrids further complicate the problem. This thesis develops a computationally fast and reasonably accurate power distribution restoration scheme enabling optimal coordination of different generators with optimal islanding. Numerical tests are conducted on benchmark water and power networks to corroborate the claims of the developed formulations.
36
Ainah, Priye. "Coordinated active power reduction strategy for voltage rise mitigation in LV distribution network." Thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/28351.
Full textAbstract:
Integration of renewable energy systems by the utility, customers, and the third party into the electric power system, most especially in the MV and LV distribution networks grew over the last decade due to the liberalization of the electricity market, rising energy demand, and increasing environmental concern. The distributed rooftop PV system contributes to relieve the overall load, reduce losses, avoid conventional generation upgrade, and better matching of demand on the LV distribution network. Originally, the LV distribution network is designed for unidirectional current flow, that is from the substation to customers. However, a high penetration of rooftop solar PVs (with power levels typically ranging from 1 – 10 kW) may lead to the current flowing in the reverse direction and this could result in a sudden voltage rise. These negative impacts on the network have discouraged the distribution network operators (DNOs) to allow increased PV penetration in the LV distribution network because some customers load, and equipment are sensitive to voltage perturbation. Presently, the most applied voltage rise mitigation strategy for high rooftop solar PV penetration is the total disconnect from the LV distribution network when the voltage at the point of common coupling (PCC) goes above statutory voltage limits. However, the sudden disconnection of the PV system from the grid can cause network perturbation and affect the security of the network. This action may also cause voltage instability in the network and can reduce the lifetime of grid equipment such as voltage regulators, air conditioner etc. Due to this negative impact, different voltage rise mitigation strategies such as the active transformer with on load tap changers (OLTC), distributed battery energy storage system and reactive power support (D-STATCOM, etc.) have been used to curtail voltage rise in the distribution network. However, the implementation of D-STATCOM device on a radial LV distribution network results in high line current and losses. This may be detrimental to the distribution network. Therefore, in this thesis, a coordinated active power reduction (CAPR) strategy is proposed using a modified PWM PI current control strategy to ramp down the output power and voltage of a grid-tied voltage source inverter (VSI). In the proposed strategy, a reactive reference is generated based on the measured voltage level at the PCC using a threshold voltage algorithm to regulate the amplitude of the modulating signal to increase the off time of the high frequency signal which shut down the PV array momentary in an extremely short time and allow the VSI to absorb some reactive power through the freewheeling diode and reduce voltage. The proposed CAPR strategy was designed and simulated on a scaled down simple radial LV distribution network in MATLAB®/Simulink® software environment. The results show that the CAPR can ramp down the PV output power, reduce reverse power flow and reduce the sudden voltage rise at the point of common coupling (PCC) within ±5% of the standard voltage limit. The study also compares the performance of the proposed CAPR strategy to that of the distributed static compensator (D-STATCOM) and battery energy storage system (BESS) with respect to response time to curtail sudden voltage rise, losses and reverse power flow. The investigation shows that the D-STATCOM has the faster response time to curtail voltage rise. However, the voltage rise reduction is accompanied by high current, losses and reverse active power flow. The introduction of the BESS demonstrates better performance than the D- STATCOM device in terms of reverse power flow and losses. The CAPR strategy performs better than both D-STATCOM and BESS in terms of line losses and reverse power flow reduction.
37
Hämäläinen, J. (Joona). "Register-transfer-level power profiling for system-on-chip power distribution network design and signoff." Master's thesis, University of Oulu, 2019. http://jultika.oulu.fi/Record/nbnfioulu-201905141744.
Full textAbstract:
Abstract. This thesis is a study of how register-transfer-level (RTL) power profiling can help the design and signoff of power distribution network in digital integrated circuits. RTL power profiling is a method which collects RTL power estimation results to a single power profile which then can be analysed in order to find interesting time windows for specifying power distribution network design and signoff.
The thesis starts with theory part. Complementary metal-oxide semiconductor (CMOS) inverter power dissipation is studied at first. Next, power distribution network structure and voltage drop problems are introduced. Voltage drop is demonstrated by using power distribution network impedance figures. Common on-chip power distribution network structure is introduced, and power distribution network design flow is outlined. Finally, decoupling capacitors function and impact on power distribution network impedance are thoroughly explained.
The practical part of the thesis contains RTL power profiling flow details and power profiling flow results for one simulation case in one design block. Also, some methods of improving RTL power estimation accuracy are discussed and calibration with extracted parasitic is then used to get new set of power profiling time windows. After the results are presented, overall RTL power estimation accuracy is analysed and resulted time windows are compared to reference gate-level time windows. RTL power profiling result analysis shows that resulted time windows match the theory and RTL power profiling seems to be a promising method for finding time windows for power distribution network design and signoff.Rekisterisiirtotason tehoprofilointi järjestelmäpiirin tehonsiirtoverkon suunnittelussa ja verifioinnissa. Tiivistelmä. Tässä työssä tutkitaan, miten rekisterisiirtotason (RTL) tehoprofilointi voi auttaa digitaalisten integroitujen piirien tehonsiirtoverkon suunnittelussa ja verifioinnissa. RTL-tehoprofilointi on menetelmä, joka analysoi RTL-tehoestimoinnista saadusta tehokäyrästä hyödyllisiä aikaikkunoita tehonsiirtoverkon suunnitteluun ja verifiointiin.
Työ alkaa teoriaosuudella, jonka aluksi selitetään, miten CMOS-invertteri kuluttaa tehoa. Seuravaksi esitellään tehonsiirtoverkon rakenne ja pahimmat tehonsiirtoverkon jännitehäviön aiheuttajat. Jännitehäviötä havainnollistetaan myös piirikaavioiden ja impedanssikäyrien avustuksella. Lisäksi integroidun piirin tehonsiirtoverkon suunnitteluvuo ja yleisin rakenne on esitelty. Lopuksi teoriaosuus käsittelee yksityiskohtaisesti ohituskondensaattoreiden toiminnan ja vaikutuksen tehonsiirtoverkon kokonaisimpedanssiin.
Työn kokeellisessa osuudessa esitellään ensin tehoprofiloinnin vuo ja sen jälkeen vuon tulokset yhdelle esimerkkilohkolle yhdessä simulaatioajossa. Lisäksi tässä osiossa käsitellään RTL-tehoestimoinnin tarkkuutta ja tehdään RTL-tehoprofilointi loisimpedansseilla kalibroidulle RTL-mallille. Lopuksi RTL-tehoestimoinnin tuloksia ja saatuja RTL-tehoprofiloinnin aikaikkunoita analysoidaan ja verrataan porttitason mallin tuloksiin. RTL-tehoprofiloinnin tulosten analysointi osoittaa, että saatavat aikaikkunat vastaavat teoriaa ja että RTL-tehoprofilointi näyttää lupaavalta menetelmältä tehosiirtoverkon analysoinnin ja verifioinnin aikaikkunoiden löytämiseen.
38
Golder, Andrew S. Miu Karen Nan. "Photovoltaic generator modeling for large scale distribution system studies /." Philadelphia, Pa. : Drexel University, 2006. http://hdl.handle.net/1860/1220.
Full text
39
Kavi, Moses. "Smart protection system for future power system distribution networks with increased distributed energy resources." Thesis, Queensland University of Technology, 2019. https://eprints.qut.edu.au/124628/1/Moses_Kavi_Thesis.pdf.
Full textAbstract:
This thesis investigates the impact of increased penetration of distributed energy resources (DERs) on the power system distribution network protection system which has been designed on the premise of passive radial network with unidirectional power flow. The investigation involved developing a multistage morphological fault detection and diagnostic tool called the decomposed open-close alternating sequence algorithm using a signal processing technique called mathematical morphology. This investigation culminated in proposing new strategies for; adaptive overcurrent protection in AC radial distribution network with increased DER penetration and high impedance arc-fault detection in AC and DC power distribution networks.
40
Nordqvist, Emil. "Preliminary design of a modular high altitude balloon power distribution system." Thesis, Luleå tekniska universitet, Institutionen för system- och rymdteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-79762.
Full textAbstract:
This thesis conducts research into different rechargeable battery technologies and their applicability to the high altitude balloon flights conducted at Esrange space center. The research focuses on the possible use of lithium ion batteries’, sodium ion batteries, nickel metal hydrate, and Metal hydridelithiumion batteries. Resulting in lithium ion batteries in 18650 cells being recommended. The thesis continues with a modular power distribution system architecture design. The system architecture is established with solarcharging capabilities, up to 1500W peak output power, over 600W continuous output power, multiple output voltages, more than six output channels, remote output power switching, and monitoring of power consumption. A prototype is built from this architecture on which limited testing is performed.The testing shines light on future improvements and displays proof of concept for some parts.
41
Moberg, Elias. "The value of flexibility in a future electric power distribution system." Thesis, Uppsala universitet, Industriell teknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-447539.
Full textAbstract:
The size and composition of the Swedish electricity generation are changing. This, in combination with new legal requirements from regulatory entities including the EU Directive 2019/944, creates several challenges for the design of the future system. Among other things, the directive suggests that flexibility solutions are to be integrated into grids to increase the degree of utilization and avoid congestions, when socio-economically profitable. This thesis evaluates what this could mean in a Swedish context, in combination with providing a basic understanding of the contradictions that can arise between a desired efficient grid use in an energy system that goes towards more distributed and intermittent energy generation sources. The work is carried out in collaboration with Vattenfall Eldistribution AB, focusing on the geographical area of Uppsala and Stockholm, the Swedish region hit hardest by local congestions. The work assumes that the economic value of a flexibility solution is at most equivalent to the cost of a conventional new construction aimed at capacity strengthening, or the Value of Lost Load (VoLL). The report’s most important deliverable is a model based on this view. The model is used to evaluate the economic value of flexibility per kWh, in three regional grid construction projects within the mentioned region. The results show that there is a great potential for using flexibility resources to increase utilization in grids and also to optimize the costs that society pays for this infrastructure by such methods. However, the work concludes that the usage of flexible technologies primarily is to adapt electric consumption with intermittent energy generation, rather than being used to solve local grid capacity shortages.
42
Ko, Chon-Sou, and 柯俊守. "Reactive Power Forecasting in Distribution System." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/97430624108936576509.
Full textAbstract:
碩士大同大學
電機工程研究所
85
The premier task of power system planning is load forecasting. Budgeting, purchasing and constructing on schedule depend on an accurate and reasonable load forecasting. In the past, load forecasting focused on real power only, but not on reactive power. Power engineers almost predicted reactive power in the light of experience value of power factor, and counted the needed quantity of capacitors. In order to estimate the reactive power reasonably and accurately, this thesis will develop an applicable method to forecast reactive power for the basis of purchasing capacitors in distribution system planning. In general, the variation of reactive power follows that of corresponding real power, and its quantity is affected by those factors, such as equipment, types of load, load composition, and so on. Each feeder is with different characteristics, so it''s not possible to adopt a formula to solve the problem for all substations. Therefore, under the consideration of easy use, less data collection and load representation of local distribution system, this thesis adopts summer peak daily records of feeders or main transformers in this year, to be trained in artificial neural network and then counts the increased amount of reactive power according to the growth or prediction of real power. It''s convenient that the daily records of DDCS system are selected as training data. For peak-VAR prediction, this thesis adopts an unconventional method which uses the hourly incremental relationship of real power and reactive power. This method can fully represent the characteristics of reactive power for various load compositions at different time period. Besides, this method also can avoid the relationship distortion between real power and reactive power with the unknown on or off status of capacitors in distribution systems.
43
CHEN, MING-TANG, and 陳明堂. "HARMONIC STUDY IN DISTRIBUTION POWER SYSTEM." Thesis, 1990. http://ndltd.ncl.edu.tw/handle/72606887704902524714.
Full textAbstract:
博士國立成功大學
電機工程研究所
79
Recently, due to the ever increasing harmonic pollution, some troublesome problems and damages have been continuously caused in the distribution power system, therefore, the harmonic processing becomes very important. In this dissertation, a microcomputer-based data acquisition system is designed to explore the possible solutions for the problems related with harmonics by the harmonic processing of the power system. The requirements for the harmonic processing, such as the frequency responses of the signal transferring devices and the highest interested harmonic order, are considered and satisfied in the design of the data acquisiton system. The overall frequency response of the system is above 3 KHz. The completed system has the outstanding characteristics, compared with the conventional method, the efficiency is higher, the cost is less and the functions are flexible. First, it is used to estimate the harmonic effect on the power component definitions and measurements on a harmonic-polluted power circuit. It is found that the conventional definitions for reactive power and distortion power are meaningless under nonsinusoidal conditions, so they must be given up, or wrong reactive power compensation may be caused from these definitions. Besides, the conventional electrodynamometer type reactive power meter and power factor meter can not be used under this condition because the operating principle of the former is based on the conventional reactive power definition and that of the latter is based on the balance of the torque in the crossed-coil under fundamental frequency. Therefore they both are inaccurate under the harmonic-polluted conditions, the reactive power measured by the reactive power meter is meaningless and the result measured by the power factor meter, under the general pollution condition in which the voltage is still sinusoidal but the current is distorted, is the displacement power factor rather than the power factor, it is always larger than the power factor. Second, it is used to evaluate the performances of the currently existing relaying algorithms for the detection of high impedance fault, after these algorithms are modeled with mathematical formulas. The evaluation is based on the processing of the signals recorded from two staged high impedance fault tests by the data acquisition system and the related relaying models. The staged fault tests were conducted on two primary distribution feeders with different load characteristics, the soil conditions under ground were also different for these two tests. The evaluated results show that all of these relaying algorithms may detect more faults than the existing commercial relays do on one feeder, but the improvements are not apparent for all of these algorithms on the other feeder. Therefore, further effort is still necessary for the related engineers and the interested researchers. However, from these test results, the characteristics of the high impedance fault are well known, and the procedure and the method used in this dissertation can be further employed to evaluate any new relaying algorithm by using the recorded signals without performing the staged high impedance fault tests which usually bring some burden to the utility and disturbance to the load. 近年來，配電系統由於日益嚴重的諧波污染，造成許多困擾與傷害。因此，諧波訊號 處理及諧波有關問題的解決，愈顯得重要與迫切。本文乃設計一微電腦資料擷取系統 ，進行若干諧波處理之研究。此資料擷取系統較傳統諧波處理方法，具有高效率，低 成本及功能彈性化之特質。其整體諧波響應超過三千赫茲，符合電力系統諧波處理的 要求。而在文中用它來研究的諧波相關問題，首先是探討諧波對傳統功率成份定義及 測量儀表的效應。結果發現，傳統功率成份中的無效功率與失真功率之定義，在諧波 污染下已失去原有意義。同時，傳統電動力矩型無效功率表在諧波污染下巷所量得的 數值，不但已失去意義，且可能造成不當的無效功率補償。另外，傳統電動力矩型功 因表，在諧波污染下亦無法正常工作方在常見的污染情況下，即電壓無污染，而電流 受到污染，其量得的數值為一般定義之基波相移因數，較實際功因還大。因此也會造 成錯誤的功因補償或對諧波產生設備之功因特性不實的評估。其次是以諧波處理技巧 ，評估諧波原之一的一次配電系統高阻抗故障現有數種較可行偵測方法的偵測性能， 以期對高阻抗故障特性和偵測，有較徹底的瞭解，進而加快此問題的解決。結果證實 這些方法，在某種負載及接地狀況下，偵測效果有顯著改善。但是在一種情形下效果 並不理想。因此，對這一深深困擾配電系統保護工程人員的故障，仍有待更進一步的 努力，以求得更可靠的偵測方法。栭在尋求新偵測方法時，正好可經由本研究中所提 供的結果，方法及所錄製的人工高阻抗故障訊號，對新方法加以評估，而不必一再的 進行耗費龐大的人工故障試驗來作新方法的偵測性能之測試。
44
Mishra, Pushanjeet, and Abhisek Kumar Panda. "Load balancing and power factor correction in power distribution system." Thesis, 2014. http://ethesis.nitrkl.ac.in/6395/1/E-8.pdf.
Full textAbstract:
The project presents an approach for load balancing and power factor correction. First we have considered a three phase grounded load system where the supply is a three phase balanced supply. Before balancing the load and correcting the power factor it is necessary to compensate the neutral current. We propose three schemes for neutral current balancing. After that the system becomes equivalent to ungrounded star connected load. Now to carry power factor correction and load balancing we need to convert the load to delta connected load. Hence we carry out star-delta transformation and we carry out our main objective through the proposed methods.
45
Chen, Po-Tsun, and 陳柏村. "Series Power Flow Controllers in Distribution System." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/29676841527045733701.
Full textAbstract:
碩士國立臺灣大學
電機工程學研究所
89
The principal purpose of the thesis is to analyze and design a Series Power Flow Controller (SPFC). The compensator consists of a three-phase pulse-width modulated voltage-source inverter connected to a direct-current capacitor. The designed SPFC can be applied to achience the power flow control and improve power factor . This thesis begins with the basic operating principles of the Series Power Flow Controller. Then from the results of Matlab simulations and experiments, it is confirmed that the power flow, power factor and voltage dip can be entirely compensated. In this thesis, digital system architecture is used to set up the control kernel. This series power flow controller is based on a personal computer with two Adventec PCL-1800 data acquisition boards.
46
Li, Jian-Cheng, and 李建成. "Magnetic Field Distribution and Shielding for Power Transmission and Distribution System." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/73366420778801330183.
Full textAbstract:
碩士國立高雄應用科技大學
電機工程系碩士班
95
This paper presents the simulation of the magnetic field and shielding effectiveness of power transmission and distribution systems. The finite element software was applied to cater for the intensity of magnetic field caused by the transmission and distribution system. The analyzed configurations included single current carrying conductor, distribution line, high voltage transmission line, and substation. The magnetic field shielding effectiveness were studied by varying parameters of the systems including shielding pattern, distance, thickness, and materials such as copper, aluminum, iron, and steel. In addition, it is to study the effects of space arrangement and phase permutation of magnetic field reduction strategy. The magnetic field distribution and shielding effectiveness study is valuable for power companies in further planning of transmission and distribution systems.
47
Hong, Wu-Cheng, and 洪武誠. "A Computer Decision Support System for Power Distribution System Restoration." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/38901687810883401374.
Full textAbstract:
碩士中原大學
電機工程學系
88
Faulted events are unavoidable in distribution systems. As a fault occurs, the dispatchers should find the fault location, isolate the fault, and restore the power supply to the blackout but unfaulted area. The system restoration is an urgent, emergent, and complicated task. Due to the existence of numerous switching combinations available, it is hard to fulfil the restoration solely depending on the experiential rules by the human dispatchers. To improve the efficiency of restoration and reduce the burden and pressure of the dispatchers, developing a fast and effective restoration algorithm in a computer decision support system is strongly desired. The thesis, therefore, aims at establishing such a system to help the dispatchers achieve an adequate restoration strategy, while the system subjected to contingent events. According to the system status and the restoration knowledge stored, the thesis proposes an fuzzy Petri-nets (FPN) model to rapidly conclude a feasible and satisfactory restoration plan. Overcome are the disadvantages of making false decision under emergent conditions by the dispatchers. In the thesis, based on the heuristic search method, the restoration schemes are transformed into graphic representations in the FPN model. Next, defined are the local and global fuzzy variables as well as their fuzzy membership functions, corresponding to the three objective functions of concern. The most adequate restoration plan is thus achieved through inferring fuzzy rules embedded in the FPN models. The FPN model adopted in the thesis integrates the approaches of heuristic searching, the Petri-nets, and fuzzy theories, in an attempt to solve for the distribution system restoration problem efficiently, reasonably, and effectively. The objectives of the restoration scheme obtained concern: (1) as many loads restored as possible, (2) as few switches operated as possible, and (3) no devices overloaded too much, if they must be. The proposed method first defines the fuzzy sets of each of the objective functions concerned. The solution with maximal membership function after combining these three objectives is the final restoration scheme desired. Firstly, the data for the Taipower Company (TPC) typical distribution system one-line diagram and its related parameters are gathered. Based on the data obtained, the knowledge base of the FPN expert system is established. In addition, the potential fault events in the distribution systems are simulated to realize the essential database for the distribution system power restoration. To build the user interface of the FPN expert system as the data input/output mechanism, the software of Visual Basic 5.0 is adopted. Integrated with the inference engine design, the FPN structure for the distribution system restoration is achieved. To facilitate the graphic reasoning of the FPN model in the developed computer decision support system, a graphic user interface (GUI) is devised. Thanks to graphic input/output forms, the developed system is both friendly and convenient for the system dispatchers.
48
CHAU, ZHEN-YU, and 曹振裕. "Study of Power Meter Measuring on Distribution System." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/k8269n.
Full textAbstract:
碩士國立東華大學
電機工程學系
102
The losses of electricity supply refer to the amount of electricity generated and transmitted through distribution grids to the final consumers that are not paid for by the users. There are two types of the losses: technical and non-technical. The technical losses occur naturally in power dissipation in an electric system, whereas the non-technical losses are caused by human actions. The losses have a great impact on the financial viability of the power company. According to the Taiwan Power Company, for every 1% of the loss's reduction, the company can save 60 billion TWD of fuel cost. Thus, reducing the losses of the electricity supply not only reduces the generation cost of electricity, but also reduces energy consumption, carbon emission, and helps slow down global warming. The objective of this thesis is to discuss and analyze the main causes of non-technical electricity losses: diverting electric current, connecting electric service without authorization, tampering with electric meters, addition of a single-phase capacitor, connecting the diode, and research better methods and use innovative equipment for detecting abnormal electric usage. Effectively reducing non-technical electricity losses will enhance the operational efficiency of a power company and ensure fairness for their paying customers.
49
魏榮里. "Industrial power distribution system analysis based on PC." Thesis, 1990. http://ndltd.ncl.edu.tw/handle/50745700394447033517.
Full text
50
GUPTA, SHIVAM. "POWER QUALITY IMPROVEMENT IN DISTRIBUTION SYSTEM USING DSTATCOM." Thesis, 2020. http://dspace.dtu.ac.in:8080/jspui/handle/repository/19819.
Full textAbstract:
Intherecenttimes,theelectricaldistributionnetworkisfacing challengesin
maintaining powerquality(PQ)due to increasing use ofsensitive electronic
equipmentinmostoftheresidential,industrialandcommercialapplications.These
electronicequipmentsbehaveasnonlinearloadstothepowersystem network.The
custom powerdevices(CPDs)arebeingusedasremediestoimprovethePQ
problemsfacedbythepowerdistributionnetwork,thecommonlyusedCPDsareD STATCOM (distribution static compensator),UPQCs (unified power quality
conditioners),andDVR(dynamicvoltagerestorers)etc.ADSTATCOM isusedfor
eliminationofharmonicsinsourcecurrent,reactivepowercompensation,power
factorcorrectionandforloadunbalancingthroughappropriatecontrolofitsvoltage
sourceconverter(VSC).ADSTATCOMinjectscurrentintosystemtomaintainsource
currentsinusoidalandmaintainunitypowerfactorbetweensourcevoltageand
current.ThepresentworkgivesadetailedperformanceanalysisofDSTATCOM
usingtwodifferenttypesofcontrolalgorithmsforVSCi.e.synchronousreference
frame(SRF)andAdaptiveBasedcontrol.Thesecontrolschemesaremodeledand
simulatedinMATLABSIMULINKtogeneratereferencesourcecurrentandcontrol
signaltoD-STATCOM tomitigatepowerqualityproblemsunderdifferentloading
condition.Thecomparisonperformanceanalysisofbothalgorithmsonthebasisof
THD(totalharmonicdistortion)insourcecurrentispresented.Theperformanceof
DSTATCOM forreactivepowercompensation,powerfactorcorrectionandload
balancing is also analyzed using SRF and adaptive based algorithms.The
DSTATCOM isconnectedinshuntconfigurationtodistributionsystem feeding
differenttypeloads.