Causes of common faults in power cables

Electric wires and cables play a crucial role in the infrastructure construction of our country. Power cables are commonly used in urban underground power grids, power station outgoing lines, internal power supply of industrial and mining enterprises, and underwater transmission lines crossing rivers and seawater. They are composed of four parts: wire core, insulation layer, shielding layer, and protective layer, and are one of the essential materials for transmitting power and energy. They are widely used in economic production. In the event of cable failure, Not only will it threaten the safe and stable operation of the power grid, but it will also cause economic losses to enterprises. In severe cases, it can cause chain damage reactions. Therefore, how to quickly troubleshoot and solve faults, and prevent their occurrence, has become a major issue of concern in the current power industry, Wuhan Keshite Electrical Equipment Co., Ltd. has analyzed the causes of common faults in power cables and elaborated on corresponding preventive measures after years of experience and testing methods.

There are many reasons for cable faults during the normal operation of the power grid, and our company has summarized and summarized the main reasons as follows.

1.Due to various inevitable defects in the material and laying process of the cable itself, varying degrees of cable aging may occur during circuit operation due to the influence of the surrounding environment, leading to the occurrence of power faults.

2. External force damage. During the storage, transportation, laying, and operation of cables, they may be damaged by external forces, especially direct buried cables that have already been operated, which are prone to damage during ground construction in other projects. This type of accident often accounts for 50% of cable accidents.

3. The electrochemical corrosion of underground stray current or the chemical corrosion of non neutral soil makes the protective layer ineffective, and these sewage and chemical substances will corrode the cable, causing corrosion of the cable sheath, armor, etc., losing the protective effect on insulation, and subsequently leading to the occurrence of power failures.

4. Due to long-term operation of power cables exceeding the rated load, improper selection of cable voltage, sudden high voltage surge or long-term overload during operation, the insulation strength of the cables may be damaged, causing cable breakdown and shortening the service life of the cables, which has an impact on the safe operation of the power grid.

5. When laying oil-paper cables with a high drop, if there is a phenomenon of insulation oil falling down from the top, it will cause the insulation level of the cable to be low at high points.

6. The outdoor terminal head was submerged in water, and due to poor construction, the insulation adhesive was not fully filled, causing the terminal head to be submerged in water and subsequently causing an explosion. The terminal head leaks oil, damaging the sealing structure, causing the impregnation agent at the cable end to dry up, increasing thermal resistance, accelerating insulation aging, easily absorbing moisture, and causing thermal breakdown.

To sum up, the quality of power cables directly affects the operation safety of the line. Once the line cannot operate safely and stably, the life and economic losses caused by its failure are unpredictable. Therefore, our power workers should fundamentally prevent the occurrence of cable failures and minimize cable accidents, starting from the details, and strive to achieve the goal of safe and stable power supply.

Wuhan Kvtester Electrical Equipment Co., Ltd. is a high-tech enterprise specializing in power testing, testing, research and development, production, and sales of testing equipment. We have been engaged in the electrical testing industry for many years, and our products are of high quality. We welcome customers to come and purchase.