Research On The Automatic Electricity Use Restricting Load Shedding

Along with the increasing of the high-capacity generating units and several power lines on one tower,the possibility of a heavy loss of generation becomes bigger.This could lead to a serious decline in the frequency of the system and for a long time in a relatively low level.If the system frequency at this time lower than the frequency of 49.2Hz(the highest start frequency of the UFLS of the Northeast Power Network),some load should be shed to restore power system stability.If the frequency of the system at between 49.2～49.8Hz,the Electricity Use Restricting Load Shedding(EURLS) should be implemented artificially.But the artificial EURLS has two disadvantages.First,it needs a long time from the instructions issued to the load-shedding.Second,it does not distinguish between primary and secondary load when Load-shedding.This paper proposes an Automatic Electricity Use Restricting Load Shedding(AEURLS) to solve the disadvantages of the artificial EURLS.The new UFLS uses for reference of the design methods of the conventional UFLS.This paper first analyses the differences between the NUFLS and the conventional UFLS, then proposes the design principles of the AEURLS.Finally,this paper sets three schemes of the Northeast Power Network.The simulation results prove that the NUFLS could solve the disadvantages of the artificial EURLS.