Network reactive power planning considering load uncertainty using an evolutionary method

Number of pages: 107 File Format: word File Code: 32179
Year: 2014 University Degree: Master's degree Category: Electrical Engineering
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  • Summary of Network reactive power planning considering load uncertainty using an evolutionary method

    Continued master's thesis in the field of power electricity

    Abstract:

    In electrical networks, the costs caused by system losses and defects caused by voltage deviation from the permissible limits are among the biggest problems that plague power generation, transmission and distribution. Therefore, reducing the costs of planning and operating power systems, and at the same time, observing its limits and restrictions has been one of the main goals of power system designers. Using parallel capacitors and changing the ratio of Tap Changers are considered to be the most economical methods to provide reactive load and adjust voltage limits. Capacitors can reduce the size of reactive generators by reducing their load demand. Also, capacitors can reduce the current of the lines from the capacitor to the power plant and thus reduce the losses and load on the lines, transformers and transmission lines. Using the capacitor at the same time as changing the ratio of the tap changer, in addition to the mentioned cases, causes delay or elimination of capital for the development of the power network. This thesis examines how to plan capacitors by considering the uncertainties affecting the transmission network level. In this regard, the owner of the transmission network is considered as an owner-operator who seeks to minimize his costs. In order to minimize costs, the owner-operator is faced with two types of decision variables. The first category is the decision-making variables related to capacitors at the level of the transmission network, which are effective at the beginning of the planning period. Other types of control variables at the operator's disposal include tap trans adjustment, active and reactive power dispatching of generators, which will be considered during the operation period. These two categories of variables are included as variables at the disposal of the owner-operator. In other words, the owner-operator of the network seeks to minimize his investment and operation costs by making decisions related to these variables. On the other hand, parameters play a fundamental role in shaping the definition of the owner-operator planning problem. These parameters include the price, amount of consumption, price of active and reactive power and cost of capacitors, which are associated with uncertainty and their impact can be evaluated with the help of risk modeling in random planning and scenario tree on owner-operator decisions. In this thesis, the accuracy of the programmed model has been evaluated by simulating the random programming designed on IEEE 30, 57 and 118 bus networks.

    Key words: capacitor programming, uncertainty, random programming

    Chapter One

     

    1-1 Introduction

    The importance of electric energy today is not hidden from anyone. Due to the simplicity of conversion to other types of energy, ease of transfer, easy control and environmental considerations, electric energy has been used more than other types of energy. Supplying electrical energy needed by customers with the lowest price and the best possible quality is the main goal of a power system. In electrical networks, losses are one of the biggest problems that plague power generation, transmission and distribution. Therefore, reducing losses and improving the voltage profile have been the main goals of power system designers, and one of the proposed solutions to achieve these goals is the use of parallel capacitors and changing the ratio of tap changers in the network [1]. Real power is produced in power plants, while reactive power is provided in the power plant (synchronous condensers) or by installing capacitors and changing the ratio of tap changers. Using parallel capacitors and changing the ratio of Tap Changers are considered to be the most economical methods to provide reactive load. Capacitors can reduce the size of reactive generators by reducing their load demand. Also, capacitors can reduce the current of the lines from the capacitor to the power plant and thus reduce the losses and load on the lines, transformers and transmission lines. Using the capacitor at the same time as changing the ratio of the tap changer, in addition to the mentioned cases, causes delay or elimination of capital for the development of the power network.In this thesis, by using capacitors in the role of parallel admittances and changing the ratio of the TapChanger, the above objectives are achieved [2-4]. The electricity industry has always been interested in designing and operating optimally and economically, therefore reducing the annual costs in the network is essential. Therefore, in order to control the bus voltage within the minimum and maximum permissible range, in the conditions of feeding different loads, parallel capacitors are used with a change in the Tap ratio [5]. Despite extensive studies of capacitor displacement in power networks, there is a lack of in-depth investigation related to two basic issues. First, the simultaneous investigation of other variables at the operator's disposal, such as the adjustment of tap trans and capacitors in power systems, and the relationship of these activities with other parameters at the disposal of the system operator, deserve more attention. Second, the economic review and analysis based on it as a link connecting technical and economic decisions requires more attention. In addition, considering the uncertainty in the parameters affecting the anchoring is also a factor that brings a wider and more complete range of choices to the network decision makers. For this purpose, the basic question of this research is how to plan the reactive power by considering other variables and parameters available to the network decision maker. In this regard, considering the effect of load uncertainty by observing the limitations of the power range of reactive generators, the voltage range of buses, the range of Tap changes and the range of changes in shunt admittance size has been analyzed and investigated.

    Taking into account the uncertainty in the parameters affecting the decision-making activities of the network, the reactive power planning structure takes on a random image and requires reviews based on risk economic factors and scenario creation. It should be mentioned here that in order to have a suitable analysis, the planning structure requires a suitable problem solving solution. Therefore, reducing the dimensions of the problem and at the same time having accurate answers using common techniques in the literature on reducing the dimensions of the problem such as scenario reduction techniques are included in the theme of this research. In the literature, the use of intelligent optimization methods has been proposed to solve problems of such dimensions. For this purpose, in this research, the particle swarm algorithm has been used to solve the problem and have the optimal answer for network decision-making activities.

    1-3 report structure

    In the second chapter, general information about reactive power equipment and the background of the upcoming research has been discussed. The third chapter of Binary Particle Aggregation Algorithm is introduced as an innovative intelligent method in solving optimization problems. In the fourth chapter, the issue of scenario reduction and reactive power planning modeling is discussed. In the rest of this chapter, the simulation results are presented along with the economic and technical analysis of the network decision maker. In the fifth chapter, the conclusion and the proposal to continue the work are presented. Thus, reducing the cost of planning and operation of power systems in accordance with technical constraints of the system is the most fundamental goal of designers. Using capacitors and tap-changers are among the most economic tools to reach these goals. Capacitors reduce the reactive demand from generators and thus reduce the loss of the system. Using capacitors and tap-changers could deter the investment requirement of the system.

    The purpose pf this thesis is to evaluate the capacitor placement in transmission system considering uncertainty of the parameters. The owner of the transmission system is considered as an owner-operator of the system who is pursuing the minimum cost

  • Contents & References of Network reactive power planning considering load uncertainty using an evolutionary method

    List:

    Abstract:.. 1

    Chapter 1.. 2

    1-1 Introduction.. 2

    1-2 Topic plan.. 3

    1-3 Report structure.. 3

    Chapter 2 reactive power, supply equipment and its planning. 5

    2-1 General definition of reactive power.. 5

    2-2 Reactive power generation devices.. 5

    2-2-1 Synchronous generators.. 6

    2-2-2 Synchronous condensers.. 6

    2-2-3 Synchronous motors.. 6

    2-2-4 Capacitor.. 6

    2-2-5 Place of installation of capacitor.. 10

    2-2-6 Condensing to reduce losses.. 11

    2-3 Reasons for intensifying the need for capacitors in Iranian networks. 12

    2-4 Background of reactive power planning. 13

    2-5 methods used to solve the reactive power planning problem. 19

    2-5-1 Analytical methods (AM).. 20

    2-5-2 Numerical programming methods (NP) (AI).. 22

    6-2 A brief description of some algorithms based on artificial intelligence (AI). 24 2-6-1 Algorithm (PSO) Leaping.. 28

    2-6-2-5 Decoding.. 28

    2-7 Training-learning based optimization algorithm (TLBO). 29

    2-7-1 Teacher phase.. 29

    2-7-2 Learner phase.. 30

    2-8 Classification of presented works.. 30

    The third chapter of PSO algorithm.. 33

    3-1 Overview of PSO algorithm.. 33

    3-2 Types of particle topology.. 34

    3-2-1 star topology.. 34

    3-2-2 ring topology.. 34

    3-2-3 wheel topology.. 35

    3-3 process of PSO algorithm.. 35

    3-4 steps of PSO algorithm implementation.. 37

    3-5 checking the effects of parameters PSO.. 38

    3-5-1 Acceleration constants.. 38

    3-5-2 Number of particles.. 38

    3-5-3 Maximum speed.. 39

    3-5-4 Inertia weight.. 39

    Chapter four.. 41

    4-1 Introduction.. 41

    4-2 Performance framework of beneficial owner in capacitor planning problem. 41

    4-3 scenario reduction.. 46

    4-4 scenario reduction regression algorithm.. 48

    4-5-Mathematical formulation of the problem of stochastic planning of capacitors. 49

    4-6 analytical studies.. 58

    Chapter five:.. 85

    5-1 conclusion.. 85

    5-2 suggestions.. 87

    English sources.. 88

    English summary.. 94

    Source:

     

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Network reactive power planning considering load uncertainty using an evolutionary method