Specified time consensus control of ESSs for frequency support with DFIG wind turbines

Abstract Small scale energy storage systems (ESSs) can assist grid integration of doubly fed induction generators (DFIG), potentially in power system frequency regulation. However, the extensive communication between ESSs may cause frequency response delays and may deteriorate the performance. Thus, this paper aims to propose a frequency response scheme with ESS assisted DFIGs wind turbines (WTs) via a specified time consensus (STC) approach. The load frequency control model with high penetration of WT is firstly constructed. A delay margin estimation (DME) procedure is conducted afterwards to estimate the allowable time delays for the system to provide frequency response. Meanwhile, the coordination strategy of the WTs and the ESSs is proposed for load sharing among the WT-ESS. Subsequently, the STC control for the ESSs is proposed to achieve consensus among the ESSs within a specified time requirement induced by the delay margin. Simulations are conducted to validate the effectiveness of the proposed method. The simulation results show that the DME is meaningful for shaping the allowable system time delay; the STC control can effectively smooth the power output of WTs and enhance the frequency regulation capability; comparing with conventional methods, the novel method shows faster convergence speed and better frequency regulation performance.