Abstract: This paper discusses Load Supplying Capacity (LSC). With an example of local power network,it educes the LSC value and presents the three factors influencing the LSC: network structure, distributing proportion of load, power supply configuration.Based on the theory of LSC,during the reliability calculation, the weak segment of power system is found, and the basis for the design project is provided, so as to satisfy optimal operation and planning.

Key words: load supplying capacity (LSC)； reliability； power network operation； power network planning；