Estimating Load Margins in Long-term Voltage Stability Analysis

Abstract:
This paper is aimed to estimate active and reactive power margins of loads in terms of long-term voltage stability. For this purpose, a new algorithm is proposed that is based on voltage sensitivities and a reference load margin. Estimated load margins are hereby presented as actual power values which makes them easily comprehensible. The proposed approach is validated in three case studies on the IEEE 118-bus test grid which covers voltage levels from 138 kV to 345 kV. The results show high accuracy of estimated margins where especially reactive power margins almost perfectly match their actual margins. The proposed algorithm can therefore be used to provide fast and precious information for system operators to evaluate long-term voltage stability.