Assessment of the impact of demand side management on power system small signal stability

With the increase in the scale of demand side management (DSM) activities, the load characteristic of power system at the load reduction and recovery times will experience significant changes due to DSM actions and hence affect the dynamic performance of power systems. This paper proposes a methodology to assess the effect of DSM actions on power system network performance - small signal stability of transmission network. A case study of shifting of different type of load from one hour to the other is tested and investigated to what extent the impact of these DSM activities can have on grid performance. A generic 295 bus distribution network and the IEEE standard 9-bus transmission network are used to demonstrate this effect. In the proposed methodology, different types of load sectors (domestic, commercial, industrial) with corresponding mix of load categories (small and large induction motors, constant power, constant impedance and constant current load) in each of them are modelled in DigSILENT/PowerFactory based on typical structure and composition of demand in distribution network. The paper demonstrates and quantifies the impact of the DSM actions on transmission network performance and establish the extent to which DSM can contribute, or otherwise, to power system stability. It will pave the way to development of optimal DSM that will ensure that not only total demand is managed but also the way how it should be managed in order not to endanger network performance in case of disturbances.