Assessment of Power System Cascading Failure under the Background of Direct Power Purchase by Large Consumers

Direct power purchase (DPP) by large consumers is an important measure of electric power market reform, which is conducive to improving the level of optimal allocation of power resources. From the perspective of safe operation of power system, it is urgent to study the influence of DPP on cascading failure in power system. In this paper, the model of DPP and cascading failure in power system are established respectively. Furthermore, three evaluation indexes, expected demand not supplied (EDNS), expected loss of nodes (ELON) and expected congestion power (ECP), are comprehensively considered, so as to propose an assessment algorithm for cascading failure in power system under the background of DPP by large consumers. The simulation results of the IEEE-RTS79 test system show that the established assessment algorithm can effectively analyze the consequences of cascading failure under different proportions of DPP. Finally, suggestions for determining the scale of DPP and active defensive measures are put forward.