Performance evaluation of SSCI damping controller based on the elastic energy equivalent system

This paper proposes an Elastic Energy Equivalent System (EEES) for evaluating the performance of sub-synchronous control interaction (SSCI) damping controller. The proposed EEES can evaluate the dynamic energy exchange and dissipation of the SSCI damping controllers under various operating conditions, and pinpoint the sensitive control parameters at different oscillation frequencies in advance. First, inspired by the vibration of spring-damper system, we establish the EEES to imitate the SSCI, so as to explore the elastic energy composition of the power system integrated with the doubly-fed induction generator (DFIG). Second, the equivalent damper and spring of EEES are used to model the controllable dissipated and potential energy for the converter controller respectively, so criteria are developed to evaluate the effectiveness of the converter controller for stabilizing the system. Third, the extended state observer-based sub-synchronous damping controller (ESSDC) is proposed to mitigate the SSCI, whose performance and parameters’ sensitivities are evaluated by the proposed EEES. Finally, the accuracy of the proposed EEES and the effectiveness of the ESSDC are validated on a DFIG-integrated power system and Guyuan wind farms. The results show that the proposed ESSDC performs better than conventional controllers with satisfactory damping and robustness under the variation of operating conditions.