Cross-linked power cable
Cross linked power cable is the abbreviation for cross-linked polyethylene insulated cable. Cross linked cables are suitable for power transmission and distribution lines with AC voltage of 500KV and below. At present, the vast majority of high-voltage cables use cross-linked polyethylene insulation.
Cross linked power cables usually refer to the insulation layer of the cable using cross-linked materials. The commonly used material is cross-linked polyethylene (XLPE).
The partial discharge and high voltage test of medium voltage cross-linked power cables are carried out one by one in the shielding room. At this time, it is possible to consider replacing the insulation core for retesting. If the voltage test passes normally after replacing the core, it should be confirmed that the cable has indeed experienced breakdown. Alternatively, if the breakdown voltage shows a gradually decreasing trend, it can be determined that the cable has experienced a true breakdown phenomenon. If the breakdown voltage of the cable remains at the same value every time, it should be considered whether the end of the cable has experienced a breakdown. At this time, the door interlock switch of the partial discharge shielding room door can be manually closed, and the shielding room door can be opened to increase the voltage. Observing the breakdown phenomenon, the location of the end breakdown can be quickly determined. If after investigation, there is no breakdown at the cable end, and multiple insulated cores and cables are replaced, or even qualified cables are retested or unloaded, and the breakdown voltage remains the same value, it should be confirmed that there is a false breakdown phenomenon in the cable. The equipment should be inspected and the fault should be eliminated before testing. However, for some long single core medium voltage cross-linked cables that need to be inspected, it is also necessary to check whether they have exceeded the allowable load of the testing equipment. In this case, the testing process may also experience detuning and tripping, so do not rashly determine that the cable has broken down.
The process is to process polyethylene (PE) material with a linear molecular structure into a three-dimensional network like cross-linked polyethylene through specific processing methods. By increasing the long-term allowable working temperature from 70 ℃ to 90 ℃ (or higher) and the short-circuit allowable temperature from 140 ℃ to 250 ℃ (or higher), the actual performance has been improved while maintaining its original excellent electrical performance.