Distribution Network Fault Location Method Based On Transient Mutation

The neutral point grounded by arc suppression coil is helpful to improve the reliability of power supply,but the weak single-phase grounding fault current increases the difficulty of detection,so the existing fault identification and section location methods still have shortcomings.Based on the study of the characteristics of transient phase current and voltage sudden change,this paper aims to explore a new method of fault identification and section location which can be easily realized in engineering practice.When a single-phase ground fault occurs at the neutral point of the distribution network through the arc suppression coil,the current and voltage at the fault detection point will suddenly change,which provides a theoretical support for fault identification;there are obvious differences in the polarity of the upstream and downstream phase voltage and phase current at the fault point,which provides a theoretical support for section positioning.A method of single-phase ground fault identification based on wavelet transform is proposed.Firstly,based on the mechanism of wave let transform,it can be known that wavelet has high sensitivity in the analysis of mutation point;secondly,based on wavelet transform,wavelet decomposition is carried out for the phase current at any time,using wavelet modulus maximum analysis to deco mpose the phase current,which can identify the fault occurrence time with high sensitivity and accuracy;finally,through different grounding resistance,different compensation methods and different fault sections,a large number of simulation is carried out An example shows the validity and applicability of the method based on wavelet transform.When the single-phase ground fault of small current grounding system is correctly identified,In order to find the fault location further,a fault location method based on transient sudden variable is proposed.First,extract the upstream and downstream phase voltage and phase current sudden variables of the fault point according to the determined fault time;secondly,according to the upstream phase voltage sudden variable derivative of the fault point is positively correlated with the phase current sudden variable,and the downstream phase voltage derivative sudden variable and phase current sudden variable of the fault point are negatively correlated,use the correl ation coefficient method to construct the section positioning vector,screen the negative elements in the vector,and determine Finally,the effectiveness and applicability of fault location method based on transient sudden variable are verified by simulat ion examples of different grounding resistance,different compensation methods and different fault initial angle.