风力发电场35 kV小电阻接地系统零序电流保护拒动原因分析

Cause Analysis of Failure of Zero Sequence Current Protection in 35 kV Small Resistance Grounding System of Wind Power Plant

由于风力发电场多处于偏远山地、海边等地带,风电场的输变电设备选择要求必须对环境影响尽可能减小,因此风电场集电线路多采用地埋电力电缆。由于人类活动的频繁,致使电力电缆遭外力破坏情况已屡见不鲜。并且电力电缆段的增多,系统的电容电流持续增大,系统配置接地变压器的零序电流保护作为系统的总后备保护。文章对某典型风电场35 kV系统零序电流保护拒动事件为例,分析接地变零序保护拒动原因,并提出整改措施,防止此类事故的发生。

As wind farms are mostly located in remote mountainous areas,seaside and other areas,the selection of power transmission and transformation equipment of wind farms must minimize the impact on the environment.Therefore,the collection lines of wind farms mostly use buried power cables.Due to the frequent human activities,it is common for the cables in the store to be damaged by external forces.Due to the increase of power cable sections,the capacitive current of the system continues to increase,and the system is equipped with zero sequence current protection of grounding transformer as the total backup protection of the system.This paper analyzes the reasons for the failure of zero sequence protection of 35 kV system in wind power plant,and puts forward improvement measures.