| When the power system is disturbed by strong external factors(such as extreme weather,etc.),its own protection system and safety measures may still be unable to avoid the occurrence of large-scale power failure.After the occurrence of the power failure,the black start of the power system is an important remedial measure to recover the power failure loss.At present,the research on black start technology of transmission system has been relatively deep and mature,but the research on black start technology of distribution network is relatively few.With the rapid development of distributed power generation technology represented by photovoltaic and energy storage and the support of relevant national policies,the penetration rate of distributed power generation in the power system continues to rise.Using distributed power supply for black start provides a new idea for the research of black start technology of distribution network.This paper focuses on the black start technology of distribution network based on distributed power supply.First,the distributed power supply participating in the black start was evaluated.A black start performance evaluation method for distributed power supply based on interval grey relational method is proposed.Firstly,the index evaluation system was established and the index weight was calculated.Then the index weight was substituted into the interval grey relational method for the multi-attribute decision calculation,and the accurate black start performance ranking of distributed power supply was obtained.Second,in order to improve the speed and stability of black start of distribution network,isolated islands are divided based on immune genetic algorithm.The immune mechanism was integrated into the genetic algorithm,and the island division scheme was optimized with the aim of restoring the maximum important load to the condition of stable operation.The coding method of traditional algorithm is improved and a new island recognition method is proposed.Combining with the immune algorithm,this paper innovates the calculation of population similarity and the treatment of low fitness population in the iterative process.By taking IEEE69 node system as an example,the method is proved to be effective in both result excellence and operation speed.Thirdly,the recovery path of isolated island internal network is optimized.The distribution network is simplified into an undirected graph composed of nodes and edges.Firstly,the improved binary particle swarm optimization algorithm is used to solve the structure of the power supply grid,and then the classical dijkstra algorithm is used to solve the shortest recovery path.The correctness and effectiveness of this method are verified by an example of IEEE33 node system. |
