Application Of Graph Theory For Smart Distribution Network Self-healing Restoration

Self-healing of the distribution network is not only one of the key technologies of intelligent distribution network, but also an important part of the future development of smart distribution grid. Self-healing of the distribution network is a multi-constrained, multi-objective, nonlinear optimization problem.With a large number of the distributed generation access to distribution network, the dispersion, instability and intermittent characteristics of the distributed generation have increased the difficulty in self-healing of distribution network after fault, which have a negative impact on the stability of operation, economy and reliability of power supply in the distribution network system. Domestic and international research focus on self-healing technology of the grid, but less of the distribution network. Therefore, the fault self-healing technology of the distribution network has important theoretical and practical significance.On the basis of domestic and international research of self-healing control in distribution network, the basic principle and technique system of intelligent distribution network is analysised considering the definition and characteristics of the grid. In the meanwhile, the impacts on the self-healing control of the distribution generation is illustrated.Aiming at the distribution network containing distributed generation and tie switch, a service restoration algorithm based on graph theory is detailed. Firstly, the service restoration model for distribution network containing distributed generation as well as the objective functions under service restoration is developed after careful consideration among quantities of restored load, switching times of circuit breakers and load loss. Secondly, the revise of infeasible solution based on graph theory is designed as four steps, which contains the generation of the network state, network region division, network structure revise and the load checking. Then, the optimization features of Quantum Discrete Particle Swarm Optimization(QPSO) algorithm is applied to achieve the optimal objective function. Finally, the algorithm based on graph theory is proved to be good at the revise of infeasible solution through an example analysis. Finally, based on graph theory including distributed power distribution network fault self-healing algorithm method was realized by programming using MATLAB tools. The effectiveness of the proposed algorithm based on graph theory is also proved to be applied to the service restoration of power distribution network.Through the analysis of the fault self-healing in IEEE-33 node system, the superiority of the proposed algorithm based on graph theory in revising the infeasible solutions among the iteration of algorithm and the effectiveness are also proved to be applied to the service restoration of distribution network.