变压器局部放电多频段联合检测技术试验研究

Experimental Study on Combined Multi-band Detection Technology for Partial Discharge in Transformer

单一的检测手段在变压器局部放电检测中均存在一定的局限性,很难全面解决变压器局部放电中的各种问题。为了克服单一检测的局限性,提高局部放电检测可靠性,文中提出基于特高频、高频和超声检测的联合检测技术,以全面解决局部放电中的抗干扰、模式识别、定位和放电量测定等问题。同时,以变压器模型中的尖端缺陷为基础,试验验证了联合检测的有效性,试验结果表明:联合检测可以有效区分内部放电和外部干扰,显著提升抗干扰能力;利用联合检测所得到的放电三维谱图可开展多种方式的模式识别技术,提高模式识别的准确度;以特高频信号为参考时标,提高了超声波信号时延的求取精度,进而提升了缺陷的定位精度;最后利用高频信号的标定结果,可获得放电的视在放电量,准确评估放电严重程度。

For partial discharge in transformer, every single detection method has its limitation and cannot solve all the problems perfectly. To overcome the limitation of single detection method and improve the reliability of partial discharge detection, this study proposed a combined detection technology based on the ultra-high frequency method, HFCT method and the ultrasonic method. The effectiveness of the combined detection method was confirmed by ex- periment, and the result shows that： 1）the discharge signal and interfere signal can be distinguished by the combined detection method effectively, and good anti-interfere performance is obtained; 2）based on the combined detection method, different kinds of pattern recognition methods could be developed to improve the accuracy of pattern recognition; 3）the discharge source location method based on the time-delay of uhrasonic signal to UHF signal has high precision; and 4）the high-frequency signal of discharge can be obtained to calculate apparent charge, thus the level of discharge can be evaluated exactly.