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Reactive Power (Var) Compensation For Voltage Stability Improvement In Power System Network

Reactive power compensation, a crucial aspect of voltage stability enhancement within power system networks, involves the provision of reactive power (measured in vars) to counterbalance the reactive power demand, thereby maintaining voltage levels within acceptable limits. This compensation mechanism plays a vital role in mitigating voltage fluctuations, enhancing system reliability, and ensuring efficient power transmission. By strategically deploying devices such as capacitors and reactors, power system operators can optimize voltage profiles, minimize line losses, and improve overall network performance. The integration of reactive power compensation techniques not only enhances voltage stability but also contributes to grid resilience, reducing vulnerability to disturbances and enhancing system response capabilities during dynamic operating conditions.

ABSTRACT

Voltage stability problems usually occur in heavily loaded systems. While the disturbance leading to voltage collapse may be initiated by different kinds of contingencies, the underlining problem is an inherent weakness in the power system. This project will illustrate the basic issues related to voltage instability by considering the characteristics of transmission system and afterwards examining how we can improve voltage stability by using reactive power compensation devices. Main consideration in this project will be focused on delivering the reactive power directly to buses in a distributing system, by installing sources of reactive power. The reason is that transmission lines can be operated with varying load and nearly constant voltage at both ends if adequate sources of reactive power are available at both ends. Before these considerations, there will be the description of the voltage stability phenomena and ways of improving it, because only with the description and researches this project will be understandable and complete.

TABLE OF CONTENTS

COVER PAGE

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWLEDGEMENT

ABSTRACT

CHAPTER ONE

INTRODUCTION

1.1 BACKGROUND OF THE PROJECT

OBJECTIVE OF THE PROJECT
AIM OF THE PROJECT
SCOPE OF THE PROJECT
FACTORS CAUSING VOLTAGE INSTABILITY
OUTCOMES OF VOLTAGE INSTABILITY
ADVANTAGES OF THE PROJECT
DISADVANTAGES OF THE PROJECT

CHAPTER TWO

LITERATURE REVIEW
OVERVIEW OF STATIC VAR COMPENSATORY
REACTIVE POWER AND VOLTAGE CONTROL
SYNCHRONOUS GENERATORS
SHUNT CAPACITORS

CHAPTER THREE

METHODOLOGY

BASIC CONCEPTS AND DEFINITIONS
STATIC VAR COMPENSATOR (SVC)
MODEL OF SVC WITH PSCAD REPRESENTATION OF ITS CONTROL
SVC CONTROL SCHEME
STUDIED SYSTEM

CHAPTER FOUR

4.1 SIMULATION AND RESULTS

CHAPTER FIVE

CONCLUSION
REFERENCES

CHAPTER ONE

1.1 INTRODUCTION

Today’s changing electric power systems create a growing need for flexibility, reliability, fast response and accuracy in the fields of electric power generation, transmission, distribution and consumption. Flexible Alternating Current Transmission Systems (FACTS) are new devices emanating from recent innovative technologies that are capable of altering

voltage, phase angle and/or impedance at particular points in power systems. Their fast response offers a high potential for power system stability enhancement apart from steady- state flow control. Among the FACTS controllers, Static Var Compensator (SVC) provides fast acting dynamic reactive compensation for voltage support during contingency events which would otherwise depress the voltage for a significant length of time. SVC also dampens power swings and reduces system losses by optimized reactive power control. Power System Computer Aided Design/Electromagnetic Transients Direct Current (PSCAD/EMTDC) has been used in this paper to conduct simulations on voltage regulation at the point of connection of SVC to the system.

However, the aim of this paper is to enhance voltage stability using Static Var Compensator at the event of occurrence of fault in the system.

1.2 BACKGROUND OF THE PROJECT

Voltage stability problems usually occur in heavily loaded systems. While the disturbance leading to voltage collapse may be initiated by a different kinds of contingencies, the underlining problem is an inherent weakness in the power system. Loss of power system stability may cause a total blackout of the system. It is the interconnection of power systems, for reasons of economy and of improved availability of supply across the broader areas that makes widespread disruptions possible. Current civilization is susceptible to case of power system blackout, the consequences of systems failure are social and economic as well. Even short disturbance can be harmful for industrial companies, because restarting of process might take several hours. In recent years, voltage instability has been responsible for several major network collapses. This project will illustrate the basic issues related to voltage instability by considering the characteristics of transmission system and afterwards examining how we can improve voltage stability by using reactive power compensation devices[8,9].

1.3 OBJECTIVES OF THE PROJECT

Explaining basic principles of equipment used for improving voltage stability. Main consideration in this project will be focused on delivering the reactive power directly to bus (in this project we will consider one bus) in a distributing system, by installing sources of reactive power. The reason is that transmission lines can be operated with varying load and nearly constant voltage at both ends if adequate sources of reactive power are available at both ends. Before these considerations, there will be the description of the voltage stability phenomena and ways of improving it.

1.4 AIM OF THE PROJECT

The main aim of this work is to enhance voltage stability using Static Var Compensator at the event of occurrence of fault in the system.

1.5 SCOPE OF THE PROJECT

Power systems are complex systems consisting of large number of generating units and interconnected network of transmission lines. The voltage stability is an issue of prime importance in this complex power system network since the demand for electric power is increasing drastically. The control of reactive power in the transmission lines will enhance the voltage stability of the power system network. This paper presents the design and implementation of the Static VAR Compensator (SVC) in the transmission network for reactive power flow control to improve the voltage stability. The proposed method detects automatically the optimal number of SVCs required for the control of reactive power[10].

1.6 FACTORS CAUSING VOLTAGE INSTABILITY

The main factors causing voltage instability are:

High reactive power consumption at heavy loads
Generating stations are too far from load centres.
Source voltages are too low.
Poor coordination between various control and protective systems
The inability of the power system to meet demands for reactive power in the heavily stressed system to keep voltage in the desired range.

1.7 OUTCOMES OF VOLTAGE INSTABILITY

Loss of load in area
Tripping of transmission lines
Voltage collapse in the system.

1.8 ADVANTAGES OF THE PROJECT

The main advantage of SVCs over simple capacitor bank compensation schemes is their near-instantaneous response to changes in the system voltage.

Dynamic compensation can be achieved by SVC [12].

1.9 DISADVANTAGES OF THE PROJECT

However, static VAR compensators are more expensive than Capacitor banks