基于热电偶原理的三相变压器绕组材料检测方法

Testing Method for Winding Materials of Three-phase Transformers Based on Principle of Thermocouple

变压器的质量直接影响电网供电的安全性和可靠性,而绕组材料检测在变压器质量管控过程中变得越来越重要。文中针对油浸式三相变压器提出了一种绕组材料检测方法。该方法基于热电偶原理,通过检测仅存在于非铜绕组变压器中的寄生热电偶实现绕组材料判别。为使变压器相间产生温差,提出了一种非对称电热方法,寄生热电偶则通过检测相应的热电势来识别。为探究检测方法的可行性同时制定合适的加热时间,采用数值仿真计算了变压器的温度分布以及热电势的理论值。通过铝绕组变压器和铜绕组变压器的试验验证了检测方法的有效性。该方法简单、有效、无需特殊的检测仪器,同时适用于其他带绕组的设备。

A new method for testing winding material of an oil-immersed three-phase transformer was proposed based on the principle of thermocouple.In this method,the winding material is recognized by detecting the parasitic thermocouples which only exist in the transformer with non-copper windings.An asymmetric electric heating mode was presented to generate temperature difference among the phases of the windings,and then the parasitic thermocouples could be found out by detecting the corresponding thermal electromotive forces.In order to verify the feasibility of the proposed testing method and acquire appropriate heating time,the temperature distribution in transformer and the theoretical values of the thermal electromotive forces were numerically computed.Testing results of the transformers with respective aluminum and copper windings verified the effectiveness of the winding material testing method.This method requires no special devices,and it is simple and applicable to other power equipment with windings.