变压器铁心多点接地缺陷特征数据分析及管控措施OA

The occurrence rate of multi-point grounding defects in the core of transformers during operation is relatively high.General-ly,multi-point grounding of the core is determined based on the grounding current of the core or the insulation resistance to ground.However,the hidden dangers of unstable multi-point grounding of the core formed by reasons such as conductive bridges are difficult to be detected in time,which affects the safe and stable operation of the power grid.Based on the analysis of multi-point grounding de-fects in a 220 kV transformer core and the defect data of similar equipment,it conducts a comprehensive analysis on the characteristic data of multi-point grounding defects in the core,including the grounding current of the core,the insulation resistance of the core to ground,and the content of dissolved gases in the oil.Based on the characteristics of low discharge or circulating current overheating energy in ferromagnetic circuits,when the acetylene content in the oil of transformers of 220 kV and below suddenly increases or rea-ches about 1 μL/L,the three-ratio method is adopted to assist in analyzing the multi-point grounding defects of the core.According to relevant standards and regulations,it proposes key control measures for the design,manufacture and installation stages of transformers to ensure the safe and stable operation of the power grid.