特高压磁控式并联电抗器保护配置方案及其性能分析

Research on Protective Configuration for a UHV Magnetically Controlled Shunt Reactor

可控高抗安全运行关系到系统的无功平衡和电压稳定,对保护要求甚高。磁控式可控高抗不仅包括网侧绕组,还设有控制绕组和补偿绕组,其本体保护配置较其他类型的可控高抗更为复杂,相关研究成果鲜有报道。基于一种在我国西北地区已实际投运的特高压磁控式并联电抗器的本体结构,对其本体保护配置进行了深入探讨,结合工程经验指出了传统保护应用于磁控式可控高抗存在的问题并给出了解决方案。介绍了网侧绕组和补偿绕组的保护配置情况及相关注意事项,详细分析了控制绕组各类故障的故障特征,提出以直流母线过电压保护作为控制绕组接地故障的主保护,同时指出传统零序功率方向保护应用于控制绕组匝间和相间故障时灵敏度不足,宜采用负序功率方向保护。

The secure operation of high-voltage controllable shunt reactors （CSR） is related to reactive power balance and voltage stability of power grid, consequently CSR makes high requirement on the performance of the protection for them. The magnetically controlled shunt reactors （MCSR） is composed of working winding at grid side, control winding and compensating winding, so the configuration of the protection for CSR itself is more complex than the protection configuration for other types of HV controllable reactors, however related research achievement in this field is seldom reported. According to the main structure of a kind of UHVAC MCSR actually applied in Northwest power grid of China, the protection configuration for it is discussed in depth, and based on engineering experiences the existing problems in applying traditional protection to MCSR are pointed out and corresponding solutions are given. The configuration of protection for working winding at grid side and compensating winding as well as related matters to be paid attention to are presented, and characteristics of various failures occurred in control winding are analyzed in depth and it is put forward to take the over-voltage protection for DC buses as the main protection for control winding earth fault, at the same time the insufficient sensitivity of traditional zero-sequence directional power protection applied in phase-to-phase fault and turn-to-turn fault occurred in control windings is pointed out and it is recommended to apply negative-sequence directional power protection for control windings.