Voltage Stability of Transmission System using Series Capacitor and Static VAR Compensator

Voltage Stability of Transmission System using Series Capacitor and Static VAR Compensator
Authors:CHANDRAMOULI.B, RATANSINGH ATKAR

Abstract: Today, The power system becomes more complicated and large, just to ensure enough energy for all activities. Due to this complexity, the power engineers would face problems like power system stability and power quality, among others. The Reactive power compensation plays an important role in the planning of a power system. This ensures a satisfactory voltage profile and a reduction in power and energy losses within the system. Reactive power also maximizes the real power transmission capability of transmission lines, while minimizing the cost of compensation. The transmission capacity can be increased by using certain compensation devices. Series capacitor and static VAR compensators can contribute to power systems voltage stabilities. Combining these two methods is the subject of this paper. Effect of the presence of series capacitor on static VAR compensator controller parameters and ratings required to stabilize load voltages at certain values are highlighted. Static VAR compensator rating and controller references and gains are found in order to stabilize load voltage at certain specified values. Interrelation between these two means parameters are highlighted. The focus of this paper is on the application of Static VAR Compensator with series capacitor to solve voltage regulation and power transfer capabilities. 

Keywords: Static VAR Compensator (SVC), Thyristor Controlled Reactor (TCR), Automatic Voltage Regulator (AVR), Voltage Regulation, MATLAB. 

INTRODUCTION 

       SVC is a mature thyristor based controller that provides rapid voltage control to support electric power transmission voltages during and immediately after major system disturbances. Since the advent of deregulation and the separation of generation and transmission systems in the electric power industry, voltage stability and reactive power-related system restrictions have become an increasingly growing concern for electric utilities. With deregulation came an “open access” rule to accommodate competition that requires utilities to accept generation and load sources at any location in the existing transmission system. This “open access” structure has challenged transmission owners to continually maintain system security, while at the same time trying to minimize costly power flow congestion in transmission corridors. When voltage security or congestion problems are observed during the planning study process, cost effective solutions must be considered for such problems [5]. Traditional solutions to congestion and voltage security problems were to install new costly transmission lines that are often faced with public resistance, or mechanically-switched capacitor banks that have limited benefits for dynamic performance due to switching time and frequency.

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