基于改进过电流保护时间电流特性的保护配合优化

Protection Coordination Optimization Based on Improved Time-current Characteristics of Overcurrent Protection

目前在多源、分布式环网中应用较多的是方向过电流保护。而不同位置的保护装置时间电流特性曲线均相同可能导致继电保护配合失灵。本文提出了以所有保护装置动作时间最小为目标的参数可优化时间电流特性。本文将传统时间电流特性曲线中新增加一辅助变量,同时在满足约束条件下对所有保护总的动作时间进行优化。改进继电保护的电流时间特性可减少故障的清除时间。另外,提出了含有指数罚因子项的目标函数。所提方法不仅减少了保护装置的动作时间,也避免了配合失灵。最后在8节点系统中对比原有时间电流特性进行了分析,说明了本文所提方法的有效性。

At present,the applications of direction overcurrent protection in multi-source and distributed meshed networks are increasing.The same time current characteristic curves of the protection devices in different locations may cause malfunctioning of relays.This paper proposes a new coordination strategy which concentrates on minimising overall operation time of relays.In this paper,a new auxiliary variable is added to the traditional time current characteristic,and the total operation time of all protections is optimized under the constraint conditions.Improving the current time characteristic of relay protection reduces the time to clear the fault.In addition,an objective function with an exponential penalty factor term is included in the optimization process.The proposed method not only reduces the operating time of the protection device,but also avoids the malfunction of the cooperation.Finally,the original time-current characteristics are analyzed in an 8-node system,and the effectiveness of the proposed method is illustrated.