Southern power grid in Suzhou has become a typical large receiving-end grid and receives electricity from"west-east powertransmission"via 5 circuits of 500kV lines.The power from outer region is received through the UHV Suzhou substation and the hydro-electricity from Southwest China is received via±800kV Jinping direct-current substation.With the increase of power from outer region and eve increasing of power load

the power receiving scale in the southern grid of Suzhou is ever increasing;the southern grid in Suzhou faces such problems as power-receiving-capacity shortage and instability after serious faults.Therefore

the analysis of the maximum power receiving capacities of southern power grid in Suzhou is of importance.With consideration of grid plan and operation control

the standard deviation on measuring margin and safety of the power transmission grid is existed.In this paper

the difference between the reference standard in the grid plan and operation control of Jingsu power grid is sorted out and

on this basis

the power receiving capacity of southern grid of Suzhou at such different period as"the thirteenth five-year plan and the fourteenth five-year plan".