Synchronization Instability Mechanism of Synchronous Condensers in Renewable Energy Sending-End Power Grid

Renewable energy bases are usually equipped with a certain capacity of synchronous condenser (SC) to suppress the risks of wide-band oscillation and temporary over-voltage, so as to improve the renewable energy delivery capacity of the sending grid. However, the nearby SC have the risk of synchronization instability incase of the grid failure. Therefore, this paper studies the synchronization instability mechanism of SC. Firstly, the equivalent circuit of the renewable energy and SC joint delivery system is developed. In addition, the synchronization instability mechanism of the SC in renewable energy sending-end grid is analyzed. Moreover, the influence of the sending-end grid voltage on the synchronization instability of the SC is developed. Theoretical analysis and simulation examples show that the synchronization instability of the synchronous condenser is not only related to the bus voltage where the synchronous condenser connects, but also related to the network parameters and other node voltage levels.