A Study on Optimizing Underground Cable Maintenance and Replacement Cycles

Entering the era of the 4th Industrial Revolution, there is a growing perception that high-quality power supply to IT devices is the starting point for a new era. It is necessary to minimize power outages because they adversely inconveniently affect the entire industry in an individual's daily life. Underground cable failure is one of the leading causes of power outages. Recently, the length of underground cables has been increasing to improve the aesthetics of urban areas and secure the safety of residents, so measures are needed to prevent underground cable accidents. There is a method of collectively replacing old cables without considering the condition of individual cables. Recently, the deterioration state of cables is diagnosed through methods such as Very Low Frequency (VLF) diagnosis, and costs are reduced by selectively replacing cables. Despite the development of these diagnostic methods, no systematic management method has been proposed that considers the cost of the life cycle due to maintenance and repair of cables. Therefore, this study conducted a study to find the optimized maintenance and replacement cycle of underground cables with added economic perspective. This study seeks to find optimized maintenance and replacement cycles of underground cables that minimize power outages and increase the power supply reliability. The proposed study initially examined the actual failure rates of the underground cables, the costs of maintenance and repair of cables, and the costs caused by their failures. It then formulated an equation to find the optimal maintenance schedules. Finally, the proposed study presents three scenarios with different maintenance cycles, including the proposed optimal schedule, frequent periodic maintenance schedule, and a scenario of not performing maintenance and repairs. This study tried to calculate the maintenance and repair costs and verified the optimal cable maintenance cycle via Monte Carlo simulations.