Transformer winding deformation test instrument based on the measurement of the characteristic parameters of transformer internal winding the internal fault frequency response analysis (FRA) method which is being developed in developed countries is adopted to make an accurate judgment of transformer internal fault.
After the design and manufacture of transformer is completed the line coil and internal structure are determined. Therefore for a multi-winding transformer line coil if the voltage grade is the same and the winding method is the same the corresponding parameters (Ci Li) of each line coil should be determined. Therefore the frequency domain characteristic response of each line coil is determined accordingly and the frequency spectrum of the corresponding three-phase line coil is comparable to some extent.
The distribution parameters of transformer windings will change when short-circuit between turns and phases occurs in the test process or collision occurs in the transportation process resulting in the relative displacement of the line coil and the deformation of the line coil caused by electromagnetic tension in the short-circuit and fault state during the operation process. Then it influences and changes the original frequency domain characteristics of the transformer that is amplitude change of frequency response and resonance frequency offset. The transformer winding test instrument developed according to the response analysis method is such a novel non-destructive testing equipment for transformer internal faults. It is suitable for the internal structure fault detection of 63kV ~ 500kV power transformer.
