For backup protection against high resistive ground faults, there will be a dual polarized directional overcurrentrelay, inverse time with instantaneous trip attachment.
对于后备保护装置防止高阻抗接地故障，将配置一只双极方向过电流继电器，同瞬时跳闸附件的时间成反比。
2
The improved PSO algorithm is tested in two models, to show the effects of improvement and its ability in solving the inverse timeovercurrentrelay coordination problem when DG units are connected.