Research Of Power System Black-Start Network Partitioning Based On Minimum Path Sets

Black-start restoration after large scale blackout in the interconnected power grid is a very complicated and multi-objective decision problem. Reasonable black-start schemes play a very important role in speeding up the system restoration process and minimizing the outage lost. When the bulk power system fails, more than one unit possess the ability of self start-up and partitioning the whole system into several subsystems which are restored in parallel can greatly accelerate the restoration process. The problem of finding the optimal partitioning scheme is mainly discussed in this paper. The method of calculating the successful rate of node restoration based on the minimum path sets is applied in the network restoration, and the new partitioning criterion is put forward considering the network reliability and operational flexibility, and finally the subsystems’skeleton network is formed. Besides, according to the units’starting time limits as well as its different starting status, several indexes such as the network reconfiguration efficiency, the restoration time of the network and the restoration time variance of the subsystems are extracted to establish an optimization objective function in order to evaluate the different partitioning schemes. The cross particle swarm optimization algorithm is employed to find the best partitioning scheme.This paper specifically introduces the method to calculate the successful rate of node restoration based on minimum path sets and several modifications when applied in power system. A small scale network example is shown to demonstrate the validity of improving the reliability of restoration network when the successful rate of node restoration is taken into account in network reconfiguration process. The method proposed in this method quantifies the uncertainty of transmission lines, and makes sure that the network we got has the higher reliability than before.About the system partitioning scheme, different from before, the new partitioning criterion combines the cost of transmission lines as well as the successful rate of node restoration. And by the new criterion, the belonging zone of the node can be identified. In the subsystem, the specific restoration path is determined by the shortest time taken rule, thus the subsystem skeleton network can be formed.In the optimization of system partitioning, according to the partitioning results and the restoration status of each unit node, several indexes such as the subsystem reconfiguration efficiency, the network restoration time and the time variance of each zone are extracted to establish an optimization objective function. Together with some constrains, system partitioning optimization model is formed. The cross particle swarm optimization algorithm is used to solve this problem.The IEEE30bus system is used as an example to verify the validity of improving network reliability when successful rate of node restoration is taken into consideration in network restoration process and IEEE118bus system is employed to demonstrate the correctness and validity of the partitioning scheme proposed in this paper.