Cable sheath protection
Large cross-section 35kV power cables and 66kV, 110kV and above voltage level of power cables are single-core cable, one end of the cable metal sheath phase interconnected and grounded and the other end is not grounded, when lightning or internal over-voltage waves along the cable core flow, the cable metal sheath without ground terminal will appear higher impact overvoltage,short circuit or when the system fault current flows through the cable core, its protective layer does not also appear high groundfrequency induction overvoltage. The over-voltage can penetrate the cable outer sheath insulation, causing the cable metal sheathmulti-point ground fault, seriously affecting the normal operation of power cables or even substantially reduce cable life. Thus the power industry standard DL/T401-1991 "high voltage power cable guide for the selection," states: cable sheath must be used to limit the power cable protection metal shield (or metal sheath) on the induced voltage and over-voltage fault.
Grounded at one end of the cable company for crossover interconnection lines and cable lines designed silicon rubber cable sheath protector has the following characteristics:
1, low residual voltage using a large-capacity high-quality ZnO chip with through flow, protection ratio characteristics;
2, the maximum limit, reducing the metal sheath cable lines in frequency induction over-voltage and over-voltage shocks;
3, integrally molded silicone rubber jacket, good sealing, anti-fouling ability, light weight, small size, anti-collision, heat resistance, aging, maintenance-free;
4, such as configuration discharge counter or monitor can automatically and accurately recorded in a variety of over-voltageprotection actions under the number and quality of operation.
Power frequency resistance
2ms square wave
Currently in the market
Model number marked by country line
*Note: Residual voltage at lightning impulse current of 16kA
Cable sheath insulation withstand voltage value (DL/T401-1991) "voltage power cable guide for the selection"
Cable Rated voltage / Rated voltage system
1min Frequency withstand voltage
Workers lightning impulse withstand voltage