电缆接地箱说明书原理中英文对照-小郭..doc

ENR-JD系列电缆接地箱Principle of ENR has - JD series cable grounding ENR-JD系列电缆接地箱Principle of ENR has - JD series cable grounding 一、概述 35kV大截面电力电缆和66kV、110kV及以上电压等级的电力电缆均为单芯电缆，电缆金属护层一端三相互联并接地，另一端不接地，当雷电波或内部过电压沿电缆线芯流动时，电缆金属护层不接地端会出现较高的冲击过电压，或当系统短路事故电流流经电缆线芯时，其护层不接地端也会出现很高的工频感应过电压。上述过电压可能击穿电缆外护层绝缘，造成电缆金属护层多点接地故障，严重影响电力电缆正常运行甚至大幅减少电缆使用寿命。因此按照电力行业标准DL/T401-《高压电力电缆选用导则》的规定须采用电缆护层保护器以限制电力电缆金属护层（或金属护套）上的感应电压和故障过电压。 通常，为限制电力电缆金属护层上的感应电压和故障过电压，并避免在护层中形成环流，电缆护层一端直接接地，另一端则须通过保护器接地。如果线路较长，将电缆护层分三段（或三的倍数段）相互绝缘，分段处的护层交叉互联后通过保护器接地。 为更好的适应市场的需求，方便用户现场安装使用，直接接地箱、保护接地箱和交叉互联保护接地箱等种形式接地。An overview, 35 kv large cross-section of power cable and more than 66 kv, 110 kv voltage grade of power cable for single core cable, the cable metal protecting layer three-phase connected and grounded at one end, on the other side is not grounded, when the thunder electric wave flow, or internal overvoltage along the cable core cable metal sheath grounding terminal will be the impact of higher overvoltage, or when the system short circuit fault current flows through the cable core, the sheath is not grounded end also can appear very high induction power frequency overvoltage. Breakdown cable outer sheath insulation, the over voltage may cause the cable metal protecting layer of multipoint earthing faults, seriously affect the normal operation of power cable and even sharply reduce the service life of the cable. So according to the electric power industry standard DL/T401-2002 guidelines for the selection of hv power cable should be used in the provisions of the cable sheath protector to limit the power cable metal sheath (or metal sheath) on the induction voltage and fault overvoltage. In general, in order to limit the induction voltage on the power cable metal sheath and fault overvoltage, and avoid the formation of circulation in the sheath, the cable metal protecting layer directly grounded at one end, and the other end must through the grounding protector. If the line is longer, but also to protect