母线保护刀闸位置异常时的自适应校正

Adaptive correction scheme of switch position abnormity of busbar protection

简要分析了支路刀闸位置异常对母线保护的选择性和可靠性的影响,评估了刀闸位置异常给保护装置带来的误动或拒动的风险,提出了基于刀闸位置计算的流入流出的电流矢量和(简称IO差流)守恒原理的刀闸位置异常智能校正方案。在大差差流平衡且仅有一段母线小差IO差流不平衡时进入校正逻辑,保护尝试着将无位置支路的电流加入小差IO差流不平衡的母线。若加入后所有母线的小差IO差流均平衡,则将本支路强制置于被校正的母线上;若不平衡,则尝试加入另一条母线上。此外还论述了校正过程中用到的IO差流平衡的判别门槛以及判定校正成功的门槛的选取原则。最后通过仿真分析论述了该方案的可行性。

This paper analyzes the impact of selectivity and reliability on the bus-bar protection when branch switch position is abnormal, assesses the risk of rejection or malfunction of protection device, and presents an adaptive correction method based on the principle of current vector sum of input current and output current being conservation（referred to as IO differential current）. When the large differential current is balanced and only one length of bus-bar small differential IO current is imbalanced, the correction logic starts, protection device will try to add the no-position branch current into the busbar which has small IO differential current, after that if all busbars＇ small IO differential current are balanced, this branch will be placed on the corrected busbar compulsively; otherwise, it will try to add to other busbar. A principle of selecting the correction and discrimination threshold of IO differential current used in modifying procedure is introduced. The feasibility of the scheme proposed is verified through simulation analysis.