新型微机电抗器保护的研制与开发

RESEARCH & DEVELOPMENT OF A NEW DIGITAL SHUNT REACTOR PROTECTION

分析了目前超高压并联电抗器保护所存在的一些问题,包括电抗器匝间短路保护灵敏度与可靠性、电流互感器暂态特性不一致对差动保护的影响等。介绍了新一代数字式电抗器成套保护装置的总体设计思想(双主双后配置)、新型高灵敏度高安全可靠的匝间短路保护原理以及考虑电流互感器暂态特性不一致的差动保护原理。新型电抗器匝间短路保护由自适应补偿的零序功率方向元件、零序阻抗元件、故障开放元件、谐波闭锁元件以及具有工频变化量浮动门槛的匝间短路保护启动元件共同构成。给出了这些保护原理的数字仿真、动模试验及现场运行结果。

This paper reviews and analyzes the existing problems of shunt reactor protection, including the sensitivity and reliability of turn-to-turn fault protection, current transformer (CT) saturation of differential relay and the characteristic of overload protection. It presents the design framework of the whole set of a new digital shunt reactor protection (double main protection and double back-up protection configuration), the principle of a new generation of high-sensitive and high-reliable turn-to-turn fault protection and the scheme of differential relay protection considering different transient characteristic of current transformer. Moreover, the scheme for turn-to-turn fault protection of shunt reactor consists of adaptive compensated zero sequence direction relay, zero sequence distance relay, zero sequence current starter relay with DPFC floating threshold, fault opening relay and harmonic restraint relay. The scheme is tested in labs and in real operation conditions of power systems. The results show that the new shunt reactor protection never mal-operates and can correctly detect all the faults.