一种新的电力变压器超声局部放电定位方法研究

A Novel Ultrasonic Localization Method of Partial Discharge in Power Transformers

近年来研究者已采用多种基于超声法的定位算法来确定电力变压器内局部放电源的位置,但多数方法会忽视超声信号复杂的传播路径对局放源定位的影响,造成较大误差。本文首先分析了由局放产生的声波信号在变压器内复杂的传播过程,尤其是超声信号穿过变压器外壳后被传感器接收过程中的波形转换现象。然后根据实际变压器尺寸建立了变压器模型,该模型中任意一个节点可代表一个局放源的潜在位置。在建立的模型基础上,提出了优化传播路径搜索算法,该算法可还原声波的传播过程并计算出从潜在局放点到传感器位置间的最快路径,进而实现局放源的精确定位。最后在35 kV变压器实验平台上进行了局放定位实验,结果优化传播路径算法的平均定位误差为18.3 cm,验证了该算法的可行性与精确度。

In recent years, many localization algorithms based on ultrasonic method are used to locate the partial discharge sources in power transformers. However, most methods ignore the influence of complex propagation path of ultrasonic signal on the localization of partial discharge source, resulting in large errors. Firstly, the complex propagation process of acoustic signals generated by partial discharge in transformer was analyzed, especially the waveform conversion phenomenon in the process of ultrasonic signal passing through transformer shell and then received by sensor. Then a transformer model was established according to the actual transformer size, and any node in this model can represent a potential location of partial discharge source. Based on this model, an improved propagation route search algorithm was proposed, which can recreate the propagation process of acoustic wave and calculate the fastest routes from the potential partial discharge source to sensor, and then realize the localization of partial discharge source accurately. At last, the partial discharge localization experiments were carried out on a 35 k V transformer, and the results show that the average localization error of improved propagation route algorithm is 18.3 cm, which verifies the feasibility and accuracy of this algorithm.