基于紫外成像和改进YOLOv3的瓷悬式绝缘子放电严重程度评估

Discharge Severity Assessment of Porcelain Suspension Insulators Based on UV Images and Improved YOLOv3

悬式瓷绝缘子是电力系统使用量较大的电气设备之一,长期工作于电、热和应力等环境下会导致其绝缘性能降低,从而威胁电力系统的安全稳定运行,因此亟需开展其放电评估研究。为此,搭建了基于紫外成像的绝缘子污秽放电诊断软件和硬件平台,得到了绝缘子放电的相对光子数、相对光斑面积和相对泄漏电流等紫外量化参数,采用损失函数改进的YOLOv3进行了放电严重程度的评估,实现了基于网络超参数和激活函数的网络参数调优。研究结果表明:基于自定义的紫外量化参数和放电参数的"Insulator","Medium","Bad"和"Worse"这4个放电状态分类具有较好的适用性;在网络训练和识别过程中,采用AP-loss误差函数对网络进行优化,经过1000次迭代,其网络误差相比于交叉熵损失函数降低了88.5%,相比于focal loss降低了54%;基于分类准确度、平均准确度均值和召回率等表征参数研究,优化了网络学习率等调参策略和激活函数的选取原则,在测试集上的准确度提高了2.5%。论文方法和结论对现场瓷绝缘子污秽放电评估检测具有一定的工程指导意义,可为低值零值绝缘子的研究提供参考。

Suspension porcelain insulator is widely used in power system,and its insulation performance may decrease and thus will seriously threaten the safe and stable operation of power system after a long-term operation in electrical,thermal and stress environments.Therefore,the research on discharge assessment is urgently needed.In this paper,a software and hardware platform for insulator pollution discharge assessment based on UV imaging method is built.The ultraviolet quantization and discharge parameters such as relative UV count,relative spot area,and relative leakage current are obtained.The loss-function-improved YOLOv3 is selected to evaluate the discharge state,and the network parameter optimization based on network super parameters and activation function is realized.The main conclusions are as follows:with the UV quantitative parameters and discharge parameters being defined,four discharge states of"insulator","medium","bad"and"worse"are classified with a good applicability.After 1000 iterations,the network error is reduced by 88.5%compared with that obtained from the cross entropy loss function and focal loss function in the train and test period.Based on the study of the characterization parameters such as Class,mA P,and Recall,the adjustment strategy and the selection principle of activation function are confirmed,and the accuracy on the test set is improved by 2.5%.The method and conclusion of this paper have a certain engineering guiding significance for the pollution discharge assessment and detection of porcelain insulators on site,and provide references for the research of low value and zero value insulators.