Assessment of the Impact of Load Modelling and DSM on Combined Power System Angular and Frequency Stability Using Composite Stability Index

With the ever-growing requirement of system stability enhancement, a comprehensive evaluation of overall system stability is coming into research focus to better understand and implement system stability enhancement solutions. This paper proposes a novel Composite Stability Index (CSI) for unified assessment of system frequency and angular stability and illustrates its application considering transient stability, small disturbance stability and frequency stability simultaneously, to assess the impacts of different load models and Demand Side Management (DSM) scenarios on either overall or individual aspects of system stability performance. The results show that the proposed CSI could clearly indicate the distance of operation points to the stability boundary, balance different and even opposite impacts on different stability aspects and quantify the impacts of different load models and DSM deployments on overall system stability performance. The results are illustrated on an equivalent model of four realistic interconnected transmission networks in a DigSilent/PowerFactory simulation environment.