Novel fast voltage stability index (FVSI) for voltage stability analysis in power transmission system

Since a couple of decades ago, voltage stability assessment has received increasing attention due to the complexity of power systems. With the increase in power demand and limited power sources has caused the system to operate at its maximum capacity. Therefore, a study that is able to determine the maximum capacity limit before voltage collapse must be carried out so that necessary precaution can be taken to avoid system capacity violation. This paper presents a novel fast voltage stability index (FVSI) simplified from a pre-developed voltage stability index referred to a line initiated from the voltage quadratic equation at the sending end of a representation of a 2-bus system. The line index in the interconnected system in which the value that is closed to 1.00 indicates that the line has reached its instability limit which could cause sudden voltage drop to the corresponding bus caused by the reactive load variation. The formulated index was tested on the IEEE reliability test system in order to verify the performance of the proposed indicator. Results showed that the proposed technique is indicative in predicting the occurrence of system collapse and hence necessary action can be taken to avoid such incident.