Coding Diagnosis Method Based on Leakage Distribution Law Under Typical Winding Defects of Transformers
To address the problems of incomplete analysis of leakage flux distribution law under transformer winding defects and insufficient research on winding fault identification based on leakage flux characteristics,this paper conducts a finite element simulation study of leakage flux distribution law under different degrees,locations,and forms of winding deformation and inter-turn short-circuit with a 110kV transformer as a prototype.The results show that the leakage flux distribution pattern is less affected by the number of radial and axial deformation pies.When the same degree of deformation occurs in the high-voltage winding,the change of the leakage flux in the winding area is less affected by the deformation position.Still,the deformation position easily affects the distribution of the leakage flux in the low-and medium-voltage windings.In addition,the winding deformation at the end is more likely to cause the leakage flux change.The flux leakage change caused by the inter-turn short circuit is much larger than the winding deformation,and will additionally affect the flux leakage distribution near the tank wall.The distribution of flux leakage changes caused by inter-turn short circuits at the same position is less affected by the degree of short circuits.The turn-to-turn short circuit occurring in the low and medium voltage windings has greater damage to the distribution of the leakage flux in the higher voltage windings.Furthermore,this paper proposes a coding identification method for winding defects based on the variation of magnetic flux leakage.With the help of the support vector machine method,the data of five magnetic flux leakage monitoring points near the winding under the same defect of different degrees are classified to determine the threshold.According to the threshold value,the magnetic flux leakage changes in various places are converted into corresponding ternary numbers.Finally,a decimal code is formed to realize the positioning and identification of winding deformation and inter-turn short circuit defects.The proposed method provides a monitoring and identification method based on the flux leakage variation for transformer winding faults.By adding monitoring points and adopting higher codes to subdivide thresholds,this method can identify defects of different degrees.Relevant results have been demonstrated in 110kV transformers.
transformerwinding deformationturn-to-turn short circuitwinding defect diagnosis
国家科技期刊平台
NSTL
万方数据
维普
