Assessment of Power System Security for Different Bus Systems through FVSI/RFVSI and Fuzzy Logic Approaches

Abstract

A power grid in a nation or continent integrates utilities by generating stations and loads in order to meet power requirements. When such colossal power systems are involved in the transfer of power, the voltage stability issue typically crops up. Voltage collapse may lead to blackouts. Blackouts can only be reduced by focusing on the steady-state and dynamic operation of power systems. A possible solution may be to increase the power system infrastructure in order to endure these blackouts. Therefore, we need to distinguish the weak and less reliable buses or lines as soon as possible in the operation of the power system so that necessary actions can be taken for smooth operation or maintaining steady-state equilibrium. The weak elements may suffer outages, and that may lead to cascading outages. In this study, contingency ranking is carried out using two evaluation approaches, namely a pre-developed Fast Voltage Stability Index (FVSI) and a new Reduced Fast Voltage Stability Index (RFVSI) or the classical approach and the soft computing approach based on Fuzzy Logic (FL). The methods have been used for different bus systems such as IEEE-14, IEEE-30, and a practical Indian 62 bus system. The RFVSI is a reduced and faster version of FVSI. The outcomes of the two approaches were compared. It is found that the Fuzzy Logic (FL) approach computes the contingency ranking faster compared to the classical approaches, whereas the classical approach based on the RFVSI method calculates more correctly the contingencies and reliable results are produced.