In order to identify the faults of distribution network more comprehensively and accurately

a method of fault location and fault type identification based on grey relational degree is proposed. Three-phase currents can be transformed to 0

α and β modulus by Karrenbauer transformation. The module with more obvious change is selected

and the comprehensive module current that reflects the fault section is constructed as the feature sequence. Then

the grey correlation degree between the feature sequence of each section and the reference normal section is calculated

and the fault section is determined by comparing with the threshold value. The magnitude distortion of 0

α and β modulus before and after faults is used to classify the faults into three categories: single-phase grounding

two-phase grounding and inter-phase short-circuit faults. According to the phase-mode transformation relationships and the boundary conditions of different types of faults

different characteristic variables are selected to calculate the grey relational degree

and the calculation results are classified to determine the type of faults. The simulation results of the IEEE 33-bus distribution network model verify that the proposed method can reliably and accurately locate the fault section and identify the fault type

and is not affected by the fault type

grounding resistance and fault phase angle.