for INMR WEEKLY TECHNICAL REVIEW
在这张照片中，既避雷器和切口安装，以防止与该装置的活端意外接触设备。但是，这样的设计必须考虑的闪络的风险超出了直接接触孤单。事实上，一个普遍的误解是，如果它被覆盖它是野生动物的证明。这不一定是正确的，因为电场可延伸超出罩的物理极限。下面的图是一个概念简图，虽然场通常不会延伸超出固体绝缘，它很容易地扩展出接缝之间和周围的阻挡材料的结束。鸟和松鼠栖息或坐在，例如因此，安装螺栓，这侵犯这一关键领域闪光灯会造成电源高频引弧避雷器和闪络。动物不一定必须触摸避雷器的高压侧 - 只有足够接近它而坐在地电位。
The use of wildlife protective devices (WPDs) is only growing these days as more and more power utilities recognize the high annual cost in outages and damaged equipment that can be attributed to contact by birds and other creatures. A related and equally important issue in some countries is that more and more bird species are being classified as protected so that financial penalties may result should these be electrocuted on overhead lines.
In this photo, both arrester and cutout have devices installed to prevent accidental contact with the live end of the apparatus. But such designs must consider that the risk for flashover goes beyond direct contact alone. Indeed, a widespread misconception is that if it is covered it is wildlife proof. This is not necessarily true since electric field can extend beyond the physical limits of the cover. The figure below is a concept sketch showing that, while field usually does not extend beyond the solid insulation, it easily extends out between seams and around ends of the barrier material. A bird or squirrel perched or sitting on, e.g. a mounting bolt, which encroaches this critical flash area will therefore cause a power frequency arc and flashover of the arrester. The animal does not necessarily have to touch the arrester’s HV side – only be sufficiently close to it while sitting at earth potential.
It is obvious that the optimum design for a cover type WPD is one that does not allow any encroachment into the critical flash area and the only way to ensure this is to use a sufficiently large cover, which is simple and effective, if not necessarily aesthetically elegant.
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一个33千伏的配电线路/A 33 kV distribution line »