Research On Fault Location And Fault Recovery Of Distribution Network With Distributed Power

The operating environment of the distribution network is vulnerable to the effects of device aging,natural disasters,and inclement weather,resulting in various faults.Quickly locating faults and restoring power supply to non-faulty areas are conducive to the safe,reliable,and stable operation of the distribution network.With the large-scale grid connection of all kinds of distributed power sources,the topological structure and line power flow of distribution network are affected to some extent,and the traditional methods applied in distribution network positioning and recovery are no longer applicable.Therefore,the fault location algorithm and fault recovery method of distribution network with distributed power supply are studied in this paper.Firstly,the influence of different grid-connected locations of distributed power on fault location of distribution network is analyzed theoretically.The access of distributed power supply makes the traditional single power flow direction from the power supply to the load become bidirectional power flow,the voltage of the access point of distributed power supply is lifted,and the current in the opposite direction to the current of the main power supply is generated,which makes the traditional fault location method unable to flexibly adapt to the grid connection of distributed power supply.A 10 k V distribution network model with distributed power supply is built in MATLAB,and the three-phase short circuit fault of the distributed power supply is simulated respectively with and without grid connection.By comparing the amplitude of the short circuit current,it is verified that the access of the distributed power supply will affect the fault current in the distribution network,and then affect the accuracy of fault location.Secondly,the problem of how to use artificial intelligence algorithm in fault location of distribution network is discussed.By introducing traditional ant colony algorithm,the basic principle of applying ant colony algorithm to distribution network fault location is analyzed.And the state selection of each node in distribution network is converted to the optimal path selection of traveler problem in ant colony algorithm,so the fault location problem in distribution network is transformed into a mathematical problem of 0-1programming.The switching state of distribution network is coded and the accurate switching function and evaluation function are constructed.The method of power flow calculation of distribution network is expounded,and the corresponding node processing is done according to different types of distributed power grid connection model,which lays a good foundation for network loss calculation of fault recovery..Then,the traditional method of locating the fault location by using the out-of-limit signal of the fault current collected by the FTU device cannot dynamically adapt to the problem of distributed power supply access.The switching function and evaluation function which can dynamically adapt to the switching state of the distributed power supply are established,and the fault location problem is transformed into the optimal solution of the function.Aiming at the shortcoming that traditional ant colony algorithm is easy to fall into local optimum,the ant colony algorithm is improved by setting initial pheromone concentration,updating pheromone by stage,setting dynamic volatilization coefficient and adaptive pheromone intensity formula.Then four test functions are used to test the performance of the improved algorithm in terms of optimization speed,accuracy and stability.A distribution network fault location model based on improved ant colony algorithm is built in MATLAB,and three cases of single point fault,multi-point fault and information distortion fault are simulated and analyzed,which proves the accuracy and speed of the improved ant colony algorithm.By comparing with the traditional genetic algorithm,It is proved that the improved ant colony algorithm has good fault tolerance in fault location of distributed power supply.Finally,in order to develop a suitable method for fault recovery of distribution network,the minimum network loss of the system is taken as the objective function,and under the constraints of node voltage,network topology,branch current and branch capacity,the fault recovery model of distribution network with distributed power is established.The hybrid genetic ant colony algorithm is applied to solve the objective function,and a set of optimal switch state combinations are obtained.In addition,a ring type coding suitable for radial distribution network structure is constructed,which solves the problem that the solution space is easy to increase exponentially in traditional binary coding.By building the simulation model of IEEE33 node distribution system with and without distributed power supply in MATLAB,it is proved that the hybrid genetic ant colony algorithm can not only restore the power supply to the greatest extent,but also effectively reduce the network loss and improve the voltage level of the grid.Figure [47] table [21] reference [80]...