考虑新能源并网影响的零序过电压解列策略

Zero-sequence overvoltage splitting strategy considering the impact of new energy grid connection

目前新能源并网故障零序过压解列判据按躲过中性点直接接地系统正常运行时的不平衡电压整定,解列时间与新能源场站的变压器间隙零序过压保护配合。然而当线路发生高阻接地短路或者线路的保护Ⅱ段范围内发生故障时,该策略存在新能源大面积误解列问题。为此文章提出一种可靠防止新能源大面积误解列的零序过压解列策略的改进方法,并设计了解列判据,通过仿真以及实际故障验证了策略的有效性。结果表明,该解列策略具有高可靠性和实用性。

At present,the zero-sequence overvoltage criterion for disconnection of new energy grid-connected faults is set according to the unbalanced voltage during normal operation of the system that bypasses the direct grounding of the neutral point.The disconnection time is coordinated with the zero-sequence overvoltage of the transformer gap of the new energy access station.However,when a high resistance grounding short circuit occurs in the line or a fault occurs within the protection section II of the line,the strategy has the problem of large-scale misrepresentation of new energy.Therefore,this paper proposes an improved method of zero-sequence overvoltage fault splitting strategy that can reliably prevent new energy from misinterpreting trains in a large area,and designs the splitting criteria.Finally,the effectiveness of the strategy is verified by simulation and actual faults.The results show that the splitting strategy has high reliability and practicability.