变压器负载条件下提取铁心振动信号基频成分方法的研究

Research of method of extracting the primary frequency component of transformer's core vibrational signal under loading condition

振动法是诊断变压器运行中潜伏故障的一种有效手段,不仅能够检测出故障绕组,还能检测铁心的状况,对其进行充分的研究有良好的应用前景。本文介绍了变压器铁心振动的起因,提出了一种不必空载运行变压器即可取得变压器铁心振动信号基频成分的方法。通过设计的测试系统,本文模拟变压器实际运行时的情况,测量了不同负载电流及空载情况下变压器本体的振动加速度信号。通过拟合的负载电流与振动加速度信号基频成分的关系曲线,得到了负载电流为零时变压器振动信号基频成分的幅值,这个值与空载情况测得的振动信号基频成分相当,说明了利用这种方法可以提取出变压器铁心振动信号的基频成分用于铁心的在线监测。

The vibration method is an effective method for on line monitoring the power transformers delitescent fault. It can monitor not only the winding, but also the conditions of core. It is a recommended method that should be studied deeply. In this paper, the principle of core vibration was described, and a method extracting cores vibration signal without operating transformer at no load condition was introduced. A vibration measuring system was developed and using this system the transformers vibration accelerating signals at different on load current and no load condition were measured. From the fitted curve of on load current versus primary frequency component of vibration accelerating signal, the value of primary frequency component as the on load current was zero was gained and it was almost equivalent to the primary frequency component of vibration accelerating signal measured at no load condition. From the result of experiment, we can see this method is very useful to estimate the condition of the transformers core.