Partial system failure may cause a large area blackout

With the cross-regional interconnected power system, increasing the size of the grid, the interaction  power transformers  various subsystems and more serious, localized system failure may lead to large-scale power outages, and even the collapse of the entire power system collapse.  electric meter , as the safe operation of the power system is one of the important measures, the problem of black start is very important. With self-starting capability of the unit start without self-starting  Electric energy meter , and gradually expand the scope of the transmission system, and ultimately the entire system recovery. In the System Recovery process involves frequent operations, and therefore may cause over-voltage lines.