柔性直流配电网电流微分保护的制动策略研究

Research on Braking Strategy of Current Differential Protection for Flexible DC Distribution Network

针对柔性直流配电网电流微分保护缺少有效制动措施等问题,提出一种以电流的微分为动作量、电流微分的模值为制动量的保护方法。利用上下级线路的配合,完成具体故障位置的甄别。通过理论分析,总结出动作量与制动量的方向和大小关系,以此构建保护判据。再通过仿真验证,发生区内故障时,本级线路动作量大于制动量、下级线路制动量大于动作量,保护灵敏动作;发生区外故障时,保护也能可靠躲过,验证了该保护算法的可靠性与选择性,同时该保护结合了故障分量算法,灵敏性和耐受过度电阻能力也有一定的提高。

In view of the lack of effective braking measures in the current differential protection of flexible DC distribution networks,a protection method is proposed that takes the differential of the current as the action amount and the modulus of the current differential as the braking amount.Use the cooperation of the upper and lower levels to complete the identification of specific fault locations.Through theoretical analysis,the relationship between the direction and magnitude of the action amount and the braking amount is summarized so as to construct the protection criterion.Through simulation verification,when an internal fault occurs,the action amount of the current level line is greater than the braking amount,and the braking amount of the lower levels line is greater than the action amount,and the protection is sensitive.The reliability and selectivity of the protection algorithm.At the same time,the protection combines the fault component algorithm,and the sensitivity and the ability to withstand excessive resistance are also improved to a certain extent.