Analysis of voltage stability enhancement of a grid and loss reduction using series FACTS controllers

Voltage stability is an issue of prime importance in the present power system scenario since the demand for electric power is increasing drastically. Voltage instability may be due to a disturbance occurring at some location in the power system. The increase in active and reactive power loss along the heavily loaded transmission network is another undesirable effect of the same. In this paper a solution to this problem is put forward by using series connected flexible AC transmission system (FACTS) controllers, namely thyristor controlled series capacitor(TCSC) and static synchronous series compensator(SSSC). The main objective of this paper is to provide adequate compensation to reduce system losses and to improve the voltage profile of the system. The optimal location for installation of the FACTS device is found out using the line stability index Lmn and validated using power flow studies. The performance of the controllers are compared to find out the best one in terms of voltage stability enhancement and loss reduction. The test has been conducted in MATLAB/PSAT environment and the test system considered is the WSCC 9 bus system.