Use of Electrical Energy Storage to Improve the Voltage Stability of a Power System with Large Amount of Wind Generation

This paper proposes the use of the energy storage system to improve the voltage stability on a small-scale South African network with a large amount of wind power generation, under both steady-state and fault conditions. Pumped-hydroelectric storage and battery energy storage system were selected and compared in DIgSILENT PowerFactory 2018 simulation software. Mathematical models and block models of the network components, battery energy storage system and pumpedhydroelectric storage models were developed and tested under steady-state operation. Three cases were studied which included the network with wind power generation, then with wind power generation and battery energy storage system and finally with wind power generation and pumped-hydroelectric storage. Results under steady-state conditions showed that the voltage levels for the four loads were within the acceptable standard voltage limits of 0.95 p.u. and 1.05 p.u. across all three cases. It was concluded that battery energy storage system is the most suitable electrical energy storage for a network with a large amount of wind generation, as it displayed the capability of maintaining the voltage levels within the acceptable voltage limits under both steady-state and fault conditions.