大型变压器绕组直流电阻的现场测试及分析

Field Test and Analysis of DC Resistance of Large Transformer Winding

文章介绍了电力变压器绕组直流电阻测试的基本原理,通过对一台大型电力变压器绕组直流电阻现场测试结果的计算分析,找出小电流测量方法在测量低压侧绕组直流电阻的不足以及产生误差的原因。采取增大测试电流,减小τ值缩短充电时间的措施,结合电压、电流表法进行试验,摸清该类型变压器低压绕组的充电规律,准确完成了直流电阻的测试。在进一步分析总结的基础上,推荐使用助磁法和增大回路电阻法,用来快速测量大型电力变压器绕组直流电阻。

This paper introduces the basic principle of DC resistance test of power transformer winding.Through the calculation and analysis of the fi eld test results of DC resistance of a large power transformer winding,it fi nds out the shortage of small current measurement method in measuring DC resistance of low-voltage side winding and the cause of error.The measures of increasing the test current and reducing the value to shorten the charging time are taken.The test is carried out by combining the voltage and ammeter method to fi nd out the charging law of the low-voltage winding of this type of transformer and accurately complete the DC resistance test.On the basis of further analysis and summary,it is recommended to use the magnetic aid method and the increasing loop resistance method to measure the DC resistance of large power transformer windings quickly.