MODELLING AND CONTROL OF STATCOM FOR IMPROVEMENT OF SMALL SIGNAL STABILITY OF SINGLE MACHINE SYSTEM

Abstract

The static synchronous compensator (STATCOM) is being increasingly employed in modem power systems due to its capability to work as var generation and absorption systems. Besides the main task of voltage control, it is also applied to improve the transmission capability and power system stability. STATCOM is mainly used to perform voltage or reactive power regulation. In general, a compensator maintaining constant terminal voltage is not effective in damping of power oscillations. To damp power oscillations a supplementary control signal should be added to the STATCOM Regulator. A multi objective comprehensive control system for the STATCOM combines the main control and supplementary control to hold constant bus voltage and improve power oscillation damping. This work presents a detailed analysis of various 6-, 12-, 24-, and 48-pulse Voltage source Converters (VSC) and development of controller. A Decoupled current control strategy is implemented for a 48—pulse GTO based three level diode clamped voltage source converter based STATCOM. In addition to the main controller, a supplementary controller is designed to improve the small signal stability of single machine systems. Major part of my work refers the research work done by the A. M. Sharaf , Senior member IEEE Simulations carried out in PSCAD and Matlab show the efficacy of the controller