Research On Distribution Network Fault Line Selection And Fault Section Detection

The voltage level of 220 V ~ 10 k V power network is known as the distribution network in China.In the recent years,the demand for power quality has been increasing in the urban social level,the power supply enterprise level and the user level,which directly affects the electricity consumption experience of the users,and its operation stability and power quality directly affect the users.Therefore,the rapid response to the distribution network fault becomes an urgent need.The typical characteristics of the distribution network is a branch of the line,the network topology is complex,a variety of neutral grounding.At the same time,T-link is more and more in the distribution network.Install the feeder terminal equipment(Feeder Terminal Unit,FTU)nodes accounted for relatively low.of all faults in the power system,more than 80% of faults occur in the distribution network,and the proportion increases.Fault line selection and fault location are one of the key technologies for relay protection in distribution networks,and become the key problem in power industry.In this paper,fault line selection and fault location method of distribution network are studied,and the results are as follows:1)Steady-state analysis and transient analysis are carried out when the single-phase-to-ground fault occurs in the small-current grounding system.Steady-state analysis shows that the steady-state characteristic of the small-current grounding system is not obvious and prone to be affected when the single-phase-to-ground fault occurs.By transient analysis,the transient current is obtained when the initial phase angle of the phase voltage is 90 ° and the main phase current is 0 °.The phase current is 0 °,and the inductor current is Major component.2)The basic principle of atomic decomposition method and the advantages and disadvantages of Fourier transform and wavelet transform are introduced.The particle swarm optimization algorithm is used to accelerate the atomic decomposition method.On this basis,the line selection factor is determined and the method is used to select the line.Finally,an example is given to verify the accuracy of the algorithm.3)A new hybrid algorithm is proposed to accelerate the artificial fish swarm algorithm by binary particle swarm optimization algorithm.The example shows that the convergence speed and accuracy of the hybrid algorithm are superior to those of artificial fish swarm algorithm and particle swarm optimization algorithm.4)Establish the switch matrix of distribution network fault location to describe the topological structure of distribution network and establish the objective function of fault location.Finally,fault location is realized by hybrid algorithm.An example shows that the algorithm can achieve accurate localization when the signal has a certain degree of distortion.In this paper,a fault selection method based on particle swarm accelerated atomic decomposition method and a fault location method based on BPSO-BAFSA hybrid algorithm is proposed,Which provides a reference for fault line selection and distribution network interval positioning of small current grounding system.