当雷电流或过电压波沿电缆线芯活动时，电缆电缆金属护套或屏蔽层不接地端会出现很高的冲击电压；电缆线路正常运行时或工频短路时电缆金属护套或屏蔽层会上产生感应电压。为了限制这些过电压,电缆金属护层常采用护套或屏蔽层单端接地、交叉蠕动泵 保定建筑设计 保定网站建设 保定网站制作 保定网络公司 保定办公家具 保定轻钢别墅 互联、两端接地、中点接地等接地方式。
When lightning current or over-voltage wave moves along the cable core, high impulse voltage will appear on the ungrounded end of cable metal sheath or shielding layer; induced voltage will appear on the metal sheath or shielding layer of cable during normal operation of cable line or power frequency short circuit. In order to limit these overvoltages, the metal sheath of cable usually adopts the grounding methods of sheath or shielding layer, such as single terminal grounding, cross interconnection, two terminal grounding and neutral point groundin