Methodology for Assessment and Improvement of Long-Term Voltage Stability of Electric Power Systems

Abstract

A new methodology for the evaluation and improvement of the voltage stability of a power system is presented. After a contingency, the assessment stage starts with the Voltage Stability Margin (VSM) evaluation, using the continuation power flow technique. If VSM is lesser than a threshold, the improvement stage takes place. Four control measures are considered, in the following order: reactive power compensation, generators terminal voltage setpoint variation, active power redispatch and load shedding. The proposed methodology is tested on the New England IEEE 39-bus and IEEE 300-bus systems. The results show the ability of the proposed methodology to improve the voltage stability of a power system after a N-1 contingency and can be a valuable tool in the on-line operation of the power system.