Power cables are cables used to transmit and distribute electrical energy. Power cables are commonly used in urban underground power grids, power station outlet lines, internal power supply for industrial and mining enterprises, and power lines under river water. In power lines, the proportion of cables is gradually increasing. Power cables are cable products used to transmit and distribute high-power electrical energy in the backbone of power systems, including various voltage levels of 1-500KV and above, and various insulated power cables. The basic structure of the power cable consists of a core (conductor), an insulating layer, a shielding layer and a protective layer. Any problem in any part of it will cause a lot of trouble. The following mainly introduces common line faults and solutions.
Short-circuit fault: There are two-phase short-circuit and three-phase short-circuit, which are mostly caused by hidden dangers left in the manufacturing process.
Grounding fault: A certain core or several cores of the cable break down to the ground. The insulation resistance is lower than 10kΩ and the low resistance is grounded. Above 10kΩ is called high resistance grounding. It is mainly caused by cable corrosion, lead cracks, insulation dryness, joint processes and materials.
Broken linear fault: A core of the cable is completely broken or not completely broken. Cables can be disconnected due to mechanical damage, terrain changes, or short-circuits.
Hybrid failure: Two or more of the above faults.
External force damage: In the process of storage, transportation, laying and operation of the cable, external force damage may occur, especially the directly buried power cable that has been operated, which is easily damaged in the ground construction of other projects. Such accidents often account for 50% of cable accidents. In order to avoid such accidents, in addition to strengthening the quality of work in cable storage, transportation, laying and other aspects, it is more important to strictly implement the ground-breaking system.
Corrosion of protective layer: Electrochemical corrosion of underground stray current or chemical corrosion of non-neutral soil invalidates the protective layer and loses the protection of insulation. The solution is to install the drainage equipment in the stray current dense area; when the local soil on the power cable line contains the chemical substances that damage the cable lead pack, the cable should be installed in the tube and the neutral soil should be used as the cable liner. And cover, but also asphalt on the cable.
Overvoltage or overload operation: improper selection of cable voltage, sudden high voltage intrusion or long-term overload during operation may damage the insulation strength of the electrical power and break down the cable. This requires strengthening inspections and improving operating conditions to resolve them in a timely manner.With power tools and electrical accessories can help a lot.
Outdoor terminal head soaking water: Due to poor construction, the insulating glue is not filled, which causes the terminal head to soak in water and eventually explode. Therefore, it is necessary to strictly implement the construction process regulations, strengthen inspection and timely maintenance. The leakage of the terminal head destroys the sealing structure, so that the impregnating agent at the end of the cable is lost, the thermal resistance is increased, the insulation is accelerated and aged, and the moisture is easily absorbed, resulting in thermal breakdown. It is found that when the terminal head leaks oil, it should strengthen the inspection. In case of seriousness, it should be powered off and redone.
The above are common faults and solutions for power supply. Have you learned? If you have other problems, please feel free to communicate with us. Jecsany Electrical Equipment is a professional supplier including power fittings, cable accessories, electrical tools, insulators, arresters, fuses, disconnecting switch, transformers, and various circuit breakers, reclosers, and switchgear. Get more details about our company and products, please visit our website: https://www.jecsany.com/