Electromagnetic Transient Simulation about the Sending-End of ±800kV Yan-Huai UHVDC

Once Shenquan power plant and Zijing power plant is linked to Yanmenguan converter station, power of 2400MW is added in the sending-end of ±800kV Yan-Huai UHVDC. It’s necessary to analyse the electromagnetic transient features of the sending-end. In this paper, the electromagnetic transient model of Yan-Huai UHVDC and the sending-end system is established. Isolated island operation strategies are analyzed. Electromagnetic induction and electrostatic induction of 500kV double-circuit transmission lines are simulated. It is found that the AC/DC systems will be seriously unstable during the isolated island operation. Various strategies is analyzed. If Yan-Huai UHVDC is blocked firstly, the voltage of sending-end reaches above 2.0 p.u. rapidly. It exceeds the requirement that the overvoltage of the 500kV equipment must be below 1.4 p.u. The equipment may be damaged. It is suggested that security and stability control system cuts off generators after receiving the isolated island signal, then the DC pole control system executes the command of blocking DC system with delay of 125ms. The grounding switches of ShenquanYanmenguan transmission lines can select class B or super B to satisfy the performance of switching the induced voltage and current.