In this work, the main reasons for the breakage of 500 kV transmission line are studied. Under low temperature condition, the coverage of the ice results in the disconnection between the aluminum tube and the steel an...In this work, the main reasons for the breakage of 500 kV transmission line are studied. Under low temperature condition, the coverage of the ice results in the disconnection between the aluminum tube and the steel anchor of strain clamp. Using macroscopic analysis, structure stress analysis, force analysis and mechanical property test, the fractured strain clamps are investigated. The crimping of the aluminum tube on the polished rod not on the grooves of the steel anchor leads to the damage of the strain clamps, which is defined as improper crimping. When improper crimping emerges, there will be only friction force between the aluminum tube and the steel anchor without shear force, and the tension of the conductor will be mainly supported by the steel strands which should be supported by both the aluminum tube and steel stands. Therefore, the breaking force of the strain clamp will greatly decrease. The failure analysis helps to promote the proper hydraulic crimping process and the safe operation of the transmission line.展开更多
针对输电线路耐张线夹X射线数字成像(X-ray digital radiography, X-DR)图像检测效率较低,且人工识别易受主观因素影响的问题,提出一种基于YOLO-ISC的输电线路耐张线夹压接缺陷检测方法。首先,在YOLOv8的主干网络中引入注意力特征融合(i...针对输电线路耐张线夹X射线数字成像(X-ray digital radiography, X-DR)图像检测效率较低,且人工识别易受主观因素影响的问题,提出一种基于YOLO-ISC的输电线路耐张线夹压接缺陷检测方法。首先,在YOLOv8的主干网络中引入注意力特征融合(iterative attention feature fusion, iAFF)模块,通过逐层融合不同尺度的特征减少信息的丢失;其次,采用SimAM注意力机制、内容感知特征重组算子(content-aware reassembly of features, CARAFE)构建融合网络PANet-SC,增强了缺陷特征的表达能力;最后,将融合后的特征输入检测头YOLO Head进行分类预测。实验结果表明,所用YOLO-ISC模型在检测耐张线夹X-DR图像的平均检测精度(mean average precision, mAP)值达到92.49%,检测速度为23帧/s。针对某类缺陷检测精度不足的问题,讨论模型置信度阈值对实际检测结果的影响,降低模型的误检率。将检测结果与SSD、Faster RCNN、DETR、YOLOv8等算法进行比较,验证所用方法的有效性。展开更多
对某220 k V输电线路碳纤维复合芯导线的失效耐张线夹进行结构检测,发现铝管压接标示线定位错误造成压接后局部应力集中,线夹装配不符合规范要求。通过开展耐张线夹楔型夹握力、铝管握力和引流板温升试验,分析了线夹装配、温升对其握力...对某220 k V输电线路碳纤维复合芯导线的失效耐张线夹进行结构检测,发现铝管压接标示线定位错误造成压接后局部应力集中,线夹装配不符合规范要求。通过开展耐张线夹楔型夹握力、铝管握力和引流板温升试验,分析了线夹装配、温升对其握力的影响,指出引流板装配不良在大电流下发热使得楔型夹握力下降,铝管升温、承载并断裂致使碳纤维复合芯棒从楔型夹中脱落。提出碳纤维复合芯导线耐张线夹安装和安全运行的技术要求。展开更多
文摘In this work, the main reasons for the breakage of 500 kV transmission line are studied. Under low temperature condition, the coverage of the ice results in the disconnection between the aluminum tube and the steel anchor of strain clamp. Using macroscopic analysis, structure stress analysis, force analysis and mechanical property test, the fractured strain clamps are investigated. The crimping of the aluminum tube on the polished rod not on the grooves of the steel anchor leads to the damage of the strain clamps, which is defined as improper crimping. When improper crimping emerges, there will be only friction force between the aluminum tube and the steel anchor without shear force, and the tension of the conductor will be mainly supported by the steel strands which should be supported by both the aluminum tube and steel stands. Therefore, the breaking force of the strain clamp will greatly decrease. The failure analysis helps to promote the proper hydraulic crimping process and the safe operation of the transmission line.
文摘对某220 k V输电线路碳纤维复合芯导线的失效耐张线夹进行结构检测,发现铝管压接标示线定位错误造成压接后局部应力集中,线夹装配不符合规范要求。通过开展耐张线夹楔型夹握力、铝管握力和引流板温升试验,分析了线夹装配、温升对其握力的影响,指出引流板装配不良在大电流下发热使得楔型夹握力下降,铝管升温、承载并断裂致使碳纤维复合芯棒从楔型夹中脱落。提出碳纤维复合芯导线耐张线夹安装和安全运行的技术要求。
