基于电流突变量的自适应过电流保护新原理

针对线路外部故障切除时负荷自启动对配电网过流保护的影响，提出了一种基于电流突变量的自适应过电流保护新原理。利用线路在配电网内部故障与故障切除过程中电流存在的明显差异特征，实现对负荷自启动过程的准确识别。当连续两次检测到电流突变量大于设定门限值并满足两个判据时，即判定负荷产生自启动过程。给出了一套过电流保护整定方法，可根据负荷变化做出动态调整，从而构建自适应过电流保护方案。仿真结果表明，基于电流突变量的自适应过电流保护新原理是有效和实用的。该原理不受负荷自启动与负荷变化的影响，可有效增大后备保护的保护范围，保证了保护的可靠性和灵敏度。

A new adaptive over current protection principle based on current mutation

The influence of load self-start on the over-current protection of distribution network when external fault removal, a new principle of adaptive over-current protection based on current mutation is proposed. By using the significant differences characteristics between the current of lines in the process of distribution network internal fault and fault removal, it realizes the accurate identification of load self-starting process. When the current mutation is detected greater twice successively than the set threshold value, and meets two criterions, the load self-starting process can be determined. An overcurrent protection setting method is proposed, which can be dynamically adjusted according to the load change, so as to build an adaptive over-current protection scheme. The simulation results show that the new principle of adaptive overcurrent protection based on current mutation is effective and practical. The principle is free from the influence of load self starting and load change, which can effectively increase the protection range of the backup protection and ensure the reliability and sensitivity of the protection. This work is supported by National Natural Science Foundation of China (No. 51477090).