Transformer insulation defect analysis method based on partial dielectric loss test

Abstract

The invention discloses a transformer insulation defect analysis method based on a partial dielectric loss test. The dielectric loss test is widely applied to the analysis and diagnosis work of a transformer insulation state, but a traditional dielectric loss test method only tests the dielectric loss of a winding-iron core / a clamp / ground, and due to the fact that a negative method of wiring is usually adopted due to the limitation that a main transformer is grounded, the test accuracy is poor, and defects of a specific position cannot be effectively judged. According to a typical structure ofa large power transformer, partial testing is carried out on the dielectric loss between the transformer winding-iron core, winding-clamp and different windings by using a method of positive wiring for reducing the voltage, and combined with the analysis of an electric field coupling effect between various partial insulating media, accurate analysis and defect positioning are carried out on insulation defects between various components of a transformer. The transformer insulation defect analysis method proposed by the invention has higher defect detection efficiency and positioning accuracy.

Description

technical field [0001] The invention relates to the diagnosis of transformer insulation defects, in particular to a method for detecting and diagnosing insulation defects of transformer windings, iron cores and clips based on partial dielectric loss testing. Background technique [0002] As an important item in transformer handover, pretest, routine and diagnostic tests, dielectric loss and capacitance tests are of great significance for judging the overall dampness of transformer insulation, oil quality deterioration, and serious local defects between windings. However, different wiring methods have a great influence on the test results of dielectric loss capacitance. Standards such as DL / T474.3-2006 "Guidelines for Implementation of On-Site Insulation Tests" and JB / T501-2006 "Guidelines for Testing Power Transformers" all stipulate that the iron core and clamp should be short-circuited to ground during the test. When taking the insulation between the winding and the core,...

AI Technical Summary

Problems solved by technology

However, for large-scale power transformers, the insulation structure between the winding and the core and the clamp is relatively complex, and the insulation of each part is relatively independent and there is a complex capacitive coupling effect. In most cases, the insulation of the relatively small capacitance is defective. It will be difficult to respond to the traditional wiring method. Simply grounding the core and clamps often cannot effectively reflect the real situation of the insulation of each part.

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