Research On The Method Of Fault Diagnosis For Distribution Network Containing Distributed Power Generation

The access of a large number of inverter-type interfaces not only causes serious harmonic pollution,but also changes the source load distribution in the system.With the continuous penetration of distributed power sources into the distribution network,the original system characteristics become complicated.This in turn affects the implementation of fault diagnosis and protection measures for this type of system.In order to deal with the influence of the fault characteristics of the traditional distribution network when the distributed power is connected,it is necessary to sort out the factors that affect the fault characteristics under the grid-connected operating conditions,and different penetration levels and line impedances.For a distribution network containing distributed power sources with a relatively definite structure,the transient characteristics under grid-connected operating conditions are analyzed from the perspective of electrical quantities.Use the lowvoltage distribution network simulation model built in MATLAB/Simulink to find and verify the electrical quantities that have characterization significance for the distribution network containing distributed power.Through the combination of support vector machine(SVM)and k-nearest neighbor method(k-NN)method,the classification accuracy of various representative electrical quantities is calculated in MATLAB,and the purpose of dimensionality reduction and screening of the selected characteristic electrical quantities is achieved by comparing the degree of classification accuracy.Combine the selected characteristic electrical quantities in pairs and analyze the characteristics of the SVM in a two-dimensional plane to verify the accuracy and effectiveness of the selected characteristic inspection,thus providing a good solution or an objective and beneficial basis for the fault detection and diagnosis of distribution network with distributed power.