Synchronous Instability Mechanism and Influence Factor Analysis of Synchronous Condenser in Renewable Energy Resources Station

Power system integrating with renewable energy resources (RER) through long distance transmission is susceptible to oscillation and transient overvoltage because of its low value of the short circuit ratio, so the voltage support capability of power sending system shall be studied. The industrial community attaches great importance to the potential of the synchronous condenser (SC) in promoting the sending ability of RER stations in view of SC's excellent dynamic reactive power support capability. However, SC is faced with power angle instability when the low voltage ride through control strategy of RER does not match well. This potential problem has not caused enough attention. In this paper, the power angle characteristic of SC that is connected to RER stations is analyzed firstly, and the transient power angle instability mechanism is proposed. Moreover, the key influence factors about power angle stability of SC are elaborated, which would provide guidance for coordinate control. Cases based on time domain simulation are used to verify the effectiveness of the stability mechanism and influence factors.