电流互感器批量缺陷的成因诊断分析和模拟试验研究

拆解分析是验证电气设备缺陷原因的有效手段.GM开关站十余台同批次电流互感器投运后相继出现了电容量、介损试验不合格、油中溶解气体超注意值的问题.为探究其批量缺陷的成因,本文梳理了GM站问题互感器的缺陷表现特点,择取159间隔A相电流互感器进行了拆解分析.拆解过程中互感器各部件未见异常.鉴于此,本文利用两台LB6—110W...

Study on Diagnosis Analysis and Simulation Tests for Batch Defects of Current Transformers

Disassembly analysis is an effective way to verify the causes of defects of electric equipment.Recently,such problems as disqualified capacitance and dielectric loss as well as excessive dissolved gas in the oil are found successively on more than ten sets current transformers,which are produced in a same batch,in GM switch station.For exploring the cause of the defects,the characteristics of defects in this batch of the transformers at GM station are sorted firstly.The current transformer in phase A of bay No.159 is selected for disassembly and analysis.However,no abnormality is found in all parts of the transformer during the disassembly process.In view of this,such two defective models as“improper drying”and“oil immersion without evacuation”are prepared by the use of two sets type LB6-110W instrument transformers.And an experimental platform for applying voltage and current is set up so to simulate the development process of the defect of the current transformer at rated operating condition.It is shown by the simulation test that in case of applying voltage and current,the defects develop rapidly with short time,showing such defect features as remarkable increase of capacitance and dielectric loss,contents of H2 in excess of 10000μL/L,extremely fast gas production rate with CH4 in second place and with a small amount of C₂H₂.It is thought by comparing the feature of the defect development and analysis that the main reason for the defect of the current transformer is no filling oil at evacuation condition in the oil filling process or the vacuum cannot meet the requirement during the production period.On this basis,such suggestions as shortening detection period of the dissolved gas in the oil and use of constant voltage and current test for sampling test in the delivery is proposed in this paper.