直流保护出口时间的不确定性及其时序特性

Uncertainty and Timing Sequence Characteristic of DC Protection Trip Time

针对直流保护在交流故障下动作结果不确定的问题,就直流保护在交流故障下出口时间的不确定性及其特有的出口时序特性展开研究。首先分析了直流保护的计时原理,指出直流保护计时采用累计方式导致动作出口时间不确定;然后基于实际的控制保护模型与参数的PSCAD/EMTDC仿真平台,通过设置不同故障条件,研究不同故障、不同故障角对直流保护出口时间的影响,结果表明直流保护出口时间在不同故障和不同故障角下具有不确定性;最后分析了直流保护在交流故障下的出口时序特性,结果表明不同直流保护的出口时序配合决定了最后保护动作的结果。

In allusion to the problem of uncertainaction result of DC protection in the case of AC fault, this paper studies un- certainty and special trip timing sequence characteristic of DC protection trip time. It firstly analyzes timing principle for DC protection and points out the reason for uncertain trip time is using cumulative mode for DC protection timing. Then based on actual control protection model and PSCAD/EMTDC simulation platform for parameters, it studies influence of different faults and fault angles on DC protection trip time according to different fault conditions. Results indicate that DC protection trip time has uncertainty under different faults and fault angles. Finally it analyzes timing sequence characteristic of DC protection in the case of AC fault and the result shows different DC protection trip time coordination determines final protection result.