Technical conditions for ground potential operation
只要人體與帶電體保持足夠的安全距離,有足夠的空氣間隙,且采用絕緣性能良好的工具,通過(guò)人體的泄漏電流和電容電流都非常?。ㄎ布?jí)),這樣小的電流對(duì)人體毫無(wú)影響,因此,足以保證作業(yè)人員的安全。地電位作業(yè)法為接地體→人體→ 絕緣體→帶電體,人體與接地體基本處于同一電位上,例如:帶電測(cè)絕緣子零值、 帶電挑異物等都屬于地電位作業(yè)項(xiàng)目。
As long as the human body keeps enough safety distance from the electrified body, there is enough air gap, and the tools with good insulation performance are used, the leakage current and capacitance current passing through the human body are very small (microampere level), so the small current has no impact on the human body, so it is enough to ensure the safety of the operators. The ground potential operation method is grounding body → human body → insulator → electrified body. The human body and grounding body are basically at the same potential. For example, electrified insulator zero value measurement, electrified pick-up of foreign matters, etc. are all ground potential operation items.
但是必須指出的是,絕緣工具的性能直接關(guān)系到作業(yè)人員的安全,如果絕緣工具表面臟污,或者內(nèi)外表面受潮,泄漏電流將急劇增加。當(dāng)增加到人體的感知電流以上時(shí),就會(huì)出現(xiàn)麻電甚至觸電事故。因此在使用時(shí)應(yīng)保持工具表面干燥清潔,并注意妥當(dāng)保管防止受潮。另外對(duì)于較高電壓等級(jí)的作業(yè)時(shí),由于電場(chǎng)強(qiáng)度高、靜電感應(yīng)嚴(yán)重,還應(yīng)采取防護(hù)電場(chǎng)的措施。如在330kV及以上電壓等級(jí)的帶電線路桿塔上及變電站架構(gòu)上作業(yè)時(shí),地電位作業(yè)也須穿靜電感應(yīng)防護(hù)服、導(dǎo)電鞋等防靜電感應(yīng)措施,220kV線路桿塔上作業(yè)時(shí)宜穿導(dǎo)電鞋。
However, it must be pointed out that the performance of insulating tools is directly related to the safety of operators. If the surface of insulating tools is dirty or the internal and external surfaces are damp, the leakage current will increase dramatically. When it is increased above the perceptual current of human body, there will be an electric shock or even an electric shock accident. Therefore, the tool surface should be kept dry and clean during use, and properly kept to prevent moisture. In addition, for the operation with higher voltage level, due to the high strength of electric field and serious electrostatic induction, measures should be taken to protect the electric field. For example, when working on the live line tower with voltage level of 330kV and above and the substation structure, the ground potential operation shall also wear anti-static induction measures such as electrostatic induction protective clothing and conductive shoes, and the 220kV line tower operation shall wear conductive shoes