PREDICTION AND ENHANCEMENT OF VOLTAGE STABILITY OF POWER SYSTEMS

Abstract

There are many challenges in power system related to stability in the stressed operating condition. Voltage collapse is a frequent phenomenon in stressed condition which leads to degradation the power system performance. So, there is continuously monitoring required to prevent the voltage collapse and major blackout. For this purpose, power system is to be examined to find the weak buses so that voltage stability can be improved. For the online testing and detection of voltage instability it is required to identify the maximum load taking capacity of the system. Load dynamics is directly related to voltage stability of the bus therefore it is required to consider different load for voltage stability studies. Previously voltage stability was observed by the P-V and Q-V curves which is time consuming. There are some indexes also provided by the many researchers like L-index, fast voltage stability index (FVSI), new voltage stability index (NVSI), line stability factor (LQP), line collapse proximity index (LCPI), Lmn index, line voltage stability index (LVSI) etc. In this work a voltage stability index named as Line Collapse Proximity Index (LCPI) has been considered mainly to evaluate the voltage stability and compare with other indices FVSI, Lmn and LQP. The maximum loadability limit of load buses also find out with help of LCPI index and verified with P-V and Q-V curves. LCPI provides highly accurate results in very short time. So precisely monitoring of power system is possible so that we can take necessary action to avoid the voltage instability. LCPI is also used to identify the reactive power margin for stability. For the effectiveness of this index it is tested on IEEE-30 bus and IEEE-118 bus test system.