| Under the guidance of the “dual carbon” development goal,the grid connection speed of distributed generation(DG),mainly wind and solar energy,has been accelerated.With a large number of DGs integrated into the distribution network,the grid structure has become more complex,affecting the power flow distribution.Considering the missing and false reporting of Feeder Terminal Units(FTU),traditional fault section location methods are facing major challenges.Therefore,it is of great practical significance to study a fault section location method suitable for DGs that can accurately and quickly locate fault locations for grid safety and reliability.This paper studies fault section location based on intelligent optimization algorithms.The main contents are as follows:Firstly,through the analysis of DG grid connection,it is found that the traditional coding method and switching function are no longer applicable.A coding method suitable for DG and a switching function model considering DG investment and cutting are researched.The feasibility of this model is verified by the simple distribution network topology structure.Since the fitness function of traditional fault section location does not consider the state value of the feeder section,it causes misjudgment of fault section location.Therefore,a DG fitness function with high fault tolerance is constructed and a fault section location model based on intelligent optimization algorithm is established.Secondly,aiming at the shortcomings of the traditional whale algorithm,improvements are made in population initialization,random control parameters,and spiral position update.An improved whale optimization algorithm(IWOA)model is constructed.The effectiveness of this model is verified using 6 test functions.The results show that the IWOA algorithm has high convergence accuracy.Then,a fault section location model of DG distribution network based on IWOA is established.Through simulation comparison experiments,it is found that under the conditions of multiple DG access,single-point faults and multi-point faults in the distribution network,the IWOA algorithm can accurately and quickly locate and is superior to other algorithms.Finally,in order to better improve the accuracy of fault section location,the missing and false reporting of FTUs are considered and used as variable factors to establish a fitness function that takes into account FTU distortion variables.In view of the problem that the established fitness function increases the dimension of algorithm solution,dimension reduction is achieved by using the constraint condition strategy of distortion variables and the hierarchical model strategy of distribution network.In the distribution network hierarchical model,regional positioning is solved by IWOA algorithm.The number of feeder sections contained in the section positioning is small,which is suitable for the exhaustion method(EM)with small calculation amount and fast speed.A fault section location model considering FTU distortion is constructed.The simulation results show that the IWOA+EM algorithm has a high convergence speed in single-point and multi-point fault section location.Through fault tolerance comparison analysis,the fault section location method considering FTU distortion effectively improves the positioning accuracy of multi-DG,multi-section faults and multi-distortion distribution networks. |
