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<p> 在低压配电系统中，有变压器中性点接地和不接地<span style="text-decoration: underline;">两种系统</span>。<br /></p><p> 相应的安全措施有<strong>接地保护</strong>和<strong>接零保护</strong><span style="text-decoration: underline;">两种方式</span>。<span style="line-height: 1.6;"> </span></p><p><span style="line-height: 1.6;"> 还有一种更灵敏、更有效的保护方式：安装<strong>漏电保护开关。</strong></span></p><p><span style="line-height: 1.6;"><strong><br /></strong></span></p><p><span style="line-height: 1.6;">本节先介绍接地保护 </span><span style="line-height: 1.6;"> </span></p><p><strong>一、接地保护：</strong></p><p> <span style="text-decoration: none;"> </span>将电气设备的金属外壳和与外壳相连的金属物架与大地作电气上的连接。</p><p> <span style="line-height: 25.6px;"> </span><span style="line-height: 25.6px; color: rgb(255, 41, 65);">保护原理：<span style="line-height: 25.6px; color: rgb(0, 0, 0);">1.<span style="line-height: 25.6px;">人体电阻一般在800Ω~10KΩ，<span style="line-height: 25.6px;">保护接地电阻应≤4Ω</span></span></span></span></p><p><span style="line-height: 25.6px; color: rgb(0, 0, 0); text-decoration: none;"> 2.当电器设备的绝缘层损坏时，外壳便带电，其线路就会与大地形成一个电容。</span><span style="color: rgb(255, 41, 65); text-decoration: underline; line-height: 25.6px;"><br /></span></p><p><span style="line-height: 25.6px; color: rgb(0, 0, 0); text-decoration: none;"> 3.若无接地保护，全部电流便流经人体而触电。<br /></span></p><p><span style="line-height: 25.6px; color: rgb(0, 0, 0); text-decoration: none;"> 4.</span><span style="line-height: 25.6px; color: rgb(0, 0, 0); text-decoration: underline;">若有接地保护，人体和接地体形成<strong>并联回路</strong></span><span style="line-height: 25.6px; color: rgb(0, 0, 0); text-decoration: none;">，由于接地电阻远小于人体电阻，因此通过人体的电流很小，绝大部分电流都通过接地体，从而保证人身安全。<br /></span></p><p> <br /></p><p> </p><p style="line-height: 25.6px; white-space: normal;"> <span style="color: rgb(255, 41, 65);">注意</span><span style="color: rgb(255, 41, 65);">：</span>1.<span style="text-decoration: underline; line-height: 25.6px; color: rgb(255, 41, 65);">当有变压器中性点接地时，采用此种安全措施。</span></p><p style="line-height: 25.6px; white-space: normal;"><span style="text-decoration: underline; line-height: 25.6px; color: rgb(255, 41, 65);"><br /></span></p><p style="line-height: 25.6px; white-space: normal;"> 2.<span style="line-height: 1.6;">.三相变压器中性点的接地、三相发电机中性点接地和防雷接地等，只是叫做<strong>工作接地</strong>。</span><span style="line-height: 1.6; color: rgb(255, 41, 65); text-decoration: underline;">为防止人体触及带电外壳导致触电，而将发动机、电器的铁心及副边线圈接地等，</span><span style="line-height: 1.6; color: rgb(255, 41, 65); text-decoration: underline;">才叫做<span style="line-height: 1.6; color: rgb(0, 0, 0);"><strong>接地保护。</strong></span></span></p><p style="line-height: 25.6px; white-space: normal;"><span style="line-height: 1.6; color: rgb(255, 41, 65); text-decoration: underline;"><br /></span></p><p style="line-height: 25.6px; white-space: normal;"> 3.<span style="line-height: 25.6px;">在电子电路中接地是指接公共参考电位”零点“；</span><span style="line-height: 25.6px; color: rgb(255, 41, 65); text-decoration: underline;"><span style="line-height: 1.6;">这里的”接地“是真正的接大地，</span><span style="line-height: 25.6px;">同电子电路中的“接地“不是同一个概念。</span></span></p><p style="line-height: 25.6px; white-space: normal;"><span style="line-height: 25.6px; color: rgb(255, 41, 65); text-decoration: underline;"><span style="line-height: 25.6px;"><br /></span></span></p><p style="line-height: 25.6px; white-space: normal;"><span style="line-height: 25.6px; text-decoration: none; color: rgb(0, 0, 0);">欢迎大家访问本人的网上商城：</span><span style="line-height: 25.6px; color: rgb(0, 0, 0); text-decoration: underline;">www.tianyan888.com</span><span style="line-height: 25.6px; color: rgb(0, 0, 0); text-decoration: none;">天衍商城</span></p><p style="line-height: 25.6px; white-space: normal;"><span style="line-height: 25.6px; color: rgb(0, 0, 0); text-decoration: none;">更多笔记下期分享！</span></p><p> </p><p><br /></p>
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发表于 2020-10-20 11:44:44