Causes of Deterioration in XLPE MV Cables: A Review

Background: Power failure and its related challenges is the cause of low economic development in most developing countries. Power failure is sometimes caused by the constant technical problems experienced by power network components which are being used for electric power transmission and distribution. Most distribution and transmission substations operate at medium voltages. Medium Voltage (MV) cables provide an efficient means of power distribution to customers. In recent times, medium voltage cables with cross-linked Polyethylene are most commonly used in modern power systems compared to the classical or paper-insulated cables due to their high resistance to Partial Discharge (PD), good electrical properties, and ability to operate at high temperature levels. However, during the process of transmission the deterioration of a cable is inevitable. This reduces the reliability and efficiency of the transmission and distribution process, which is of course a serious concern to power engineers and consumers. Owing to the challenges experienced from the degradation of MV XLPE cables, it has become highly imperative to investigate the causes of failure in power network cables used for the transmission and distribution of electric power. Methods: A comprehensive review was carried out to understand the fundamental causes of MV XLPE degradation. This was pivotal in adopting the right monitoring technique for the MV XLPE cable. Results: The results show that the major causes of MV network cable faults are attributed to either material related or external causes. It was also discovered that there are different fault rates for different MV cable types. Further discoveries show that the XLPE cables failure rate is minimal compared to the Nordic Oil-paper cables which are said to have an average faults occurrences detection of about 4-5 times higher than that of the XLPE cables. Oil paper cables experience high failure rates and in addition experience substantial defects in their cable joints. Conclusion: This paper presented a comprehensive review of the causes of MV XLPE cable degradation and proffers solutions to the lingering challenges associated with MV XLPE cables.