方向纵联保护对LCC-HVDC逆变侧交流线路的适应性分析

基于电压、电流故障分量的方向纵联保护原理广泛应用于交流线路的主保护。由于LCC-HVDC逆变侧交流线路具有不同于纯交流系统的故障特性,方向纵联保护能否继续适用需加以分析。首先,分析了逆变站三种不同的工作状态(未发生换相失败、发生单次换相失败、发生连续换相失败)对方向纵联保护的影响。其次,分析了逆变侧三种典型的交流出线结构(单回线单输电走廊、单回线多输电走廊、多回线输电走廊)对方向纵联保护的影响。最后,基于±800 kV天中直流系统(包括逆变侧500 kV交流出线)PSCAD仿真模型,验证了研究结论的正确性。

Adaptability analysis of directional pilot protection for AC transmission lines connected to LCC-HVDC inverter station

Directional pilot protection principle, which is based on voltage and current fault components, is used in AC transmission lines widely. However, comparing to general AC transmission lines, the AC transmission lines which is connected to LCC-HVDC inverter station have different fault characteristic and the adaptability of directional pilot protection should be analyzed. Firstly, the effect of three different working status of inverter station (no commutation failure, single commutation failure or continuous commutation failure) on directional pilot protection is analyzed. Secondly, the effect of three different AC transmission line structures connected to inverter station (single transmission line, several single transmission lines or double transmission lines) on directional pilot protection is also analyzed. Eventually, ±800 kV Tian-Zhong LCC-HVDC transmission system (including 500 kV AC transmission system connected to inverter station) simulation model is established based on PSCAD and the simulation results prove the correctness of theoretical analysis. This work is supported by National Key Research and Development Program of China (No. 2016YFB0900603).