基于姿态估计的输电线路带电作业的人体数字孪生研究

带电作业是保证电网安全可靠运行的重要内容,而带电作业又充满危险。为了能够对人体面临的风险进行评估,可以将数字孪生理念引入输电线路带电作业中,构建人体数字孪生体对人体进行风险评估,在虚拟空间中完成对现实世界的映射。采用姿态估计、模型重构和模拟仿真构建高压输电线路带电作业人体数字孪生体,能够对危险状况进行预警,评估人身安全。首先运用POSIT算法得到现实世界和图像坐标系的转换矩阵,结合二维三维转换技术将后续的二维坐标点转换为三维坐标点,即能得到人体的姿态数据。然后利用人体姿态数据进行人体的模型重构论述和现场仿真进行风险评估,并且通过实时工作指南规则进行人员的潜在风险评估。该研究实现了三维模型随着姿态数据的改变而模型重构,继而随着人体模型的改变,系统将在仿真中自动计算电场,并利用风险评估显示危险。此技术能够为现场作业人员安全评估提供一种新的思路,为数字化电网发展提供基础。

Childhood Leukemia Not Linked with ELF Magnetic Fields

The discussion whether extremely low frequency (ELF) magnetic fields (MF) are causally linked with childhood leukemia is ongoing for almost four decades. Results of epidemiologic studies have indicated such an association might exist and led to IARC’s classification of ELF MF as possibly carcinogenic (class 2B). Although in the meanwhile many epidemiologic studies and meta-analyses of selected studies are available, this did not change the situation. By a new approach of pooling all epidemiologic data, this paper shows that it is possible to come to a convincing conclusion which explains controversial results and reports dose-response relationship, and provides answers to striking facts such as that epidemiologic results on childhood leukemia are independent from field source or exposure metric of whatever kind with no specific favorite. The analysis revealed that the assumption of a causal link between ELF MF exposure and childhood leukemia is no longer plausible and hence that ELF MF’s classification as possibly carcinogenic needs revision.

直流GIS长期带电考核试验方案

开展长期带电考核是检验开关设备性能的重要手段,目前针对直流GIS长期带电考核还缺少系统性研究和工程实践。对此,结合直流GIS设备的特点和绝缘考核水平,提出了包括4 000 A直流热效应的重载等效试验。给出了在全工况下叠加雷电冲击、操作冲击试验的长期带电考核试验方案,设计了可保证试验设备安全运行的试验回路接线方式,并在±200 kV直流GIS上开展了验证试验。结果表明,该方法能有效考核设备性能,具备可行性。