改进的配电网反时限过电流保护

Improved inverse-time over-current protection for distribution network

配电网反时限过电流保护的动作特性与保护配合会受到接入的分布式电源影响。分析了反时限过电流保护的动作特性,在此基础上提出了基于通信的反时限过电流保护方案,该保护方案借助通信信道将分布式电源支路的故障助增电流数据发送至上级线路保护,改善了保护间的配合特性。在反时限动作方程中引入低电压加速因子构成低电压加速反时限过电流保护,改进了动作方程中时间常数的整定方法,在保证上下级保护配合特性的同时加速了保护的动作时间。PSCAD仿真结果验证了所提反时限过电流保护方案的有效性。

The operating characteristic of ITOC（Inverse-Time Over-Current protection） of distribution network and its protective coordination are affected by the integration of DG（Distributed Generation）. The operating characteristic of ITOC is analyzed and a communication-based scheme is proposed,which sends the fault infeed current information of DG branch to the superordinate protection via communication channel to improve the coordination among protections. A low-voltage acceleration factor is introduced to the inversetime operation equation to form the low-voltage acceleration ITOC and the setting of its time constant is improved to guarantee both protective coordination and operating speed. The results of simulation with PSCAD verify the effectiveness of the proposed schemes.