The first switch protection setting value expected effect.
Automatic isolation fault zone.When regional single phase grounding, interphase short circuit fault occurs. According to the current cascade protect time limit and flow three sections of inverse time characteristics, and the change of the zero sequence current, membrane switch switch trip ahead of substation for protection, automatic isolation failure group road, substation to qualify, do find section switch and other branch line switch do not occur due to drop and tripping caused a power outage.
Mains failure, also won't cause substation jumped to smell and higher level in the line section switch.Ring network practice way according to different ring method, to adjust.Quickly restore power to the fault zone.In the radiant power distribution network, if the above branch line protection cause main trip. Or above thousand system lead to level one thousand line tripping, before can pressure reclosing mode through inspection. Delay time and the number of different to heal itself.Find coincidence first reach the trunk, switching path, after a successful plant have the branch switch and switch, if so the array points network blocking effect.
Second, the switch protection positioning set principles.
One is the main section switch using stepwise current protection.From the time, current value.Main thousands of circuit breaker 3-5 more appropriate, switch time value to adjust agree (section switch with some switch one more set) or level.