Optimization and coordination of under frequency load shedding(UFLS) and under voltage load shedding(UVLS) are hybrid optimization problem involving discrete and continuous variables,considering multi-condition,multi-scenario,multi-control-bus and multi-step-control.

It puts forward that in order to make the load screwdown electrode holder st real significance,we should make overall consideration and improve design level of the whole electrode system from the following fields,such as,insulation on gas and hydraulic pressure tubes,electrode shell,electrode holder,elec- trode screwdown equipments and gripping facil.