城市轨道交通引起的变压器直流偏磁噪声与振动特性

城市轨道交通的发展容易引起变压器直流偏磁问题,噪声与振动特性监测是判断变压器运行状态的重要手段。为此,研究了由城市轨道交通引起的变压器直流偏磁问题的产生机理,对直流偏磁条件下变压器的噪声与振动信号进行了现场监测,分析了直流偏磁前后变压器噪声与振动特性,从中提取了直流偏磁特征量,并将该特征量与变压器噪声与振动信号的变化趋势进行对比。结果表明,变压器直流偏磁问题的产生与城市轨道交通的运行状态有关,变压器出现直流偏磁时,其噪声、振动以及中性点直流信号急剧增大且具有相同的变化趋势,以噪声与振动信号奇偶次谐波比为特征量能够对变压器直流偏磁状态进行有效评价。

Audible noise and vibration characteristics of DC-bias in power transformers caused by urban mass transit system

DC-bias mechanism of power transformer caused by urban mass transit system is investigated in this paper . The monitoring of field audible noise and vibration measurement of power transformer is carried out in DC-bias condi-tion.The noise and vibration characteristics of power transformer before and after DC-bias are analyzed , from which the characteristic parameter of DC-bias is extracted .Time variation of the characteristic parameter is compared with that of the power transformer noise and vibration .The result shows that the occurrence of DC-bias is relevant with the regular operation state of the urban mass transit system .The signals of audible noise , vibration and direct current of the power transformer have the same variation process when DC-bias occurs.The rate of odd-to-even-order harmonic of the noise and vibration signals is obviously increased compared with that in normal condition .Therefore , it could be effectively applied in the DC-bias condition evaluation of power transformers .