Study on the extraction of cable joints and cable segment insulation resistance

Abstract

The aging of insulation in distribution cables is a critical issue affecting the safety and reliability of power systems. As the global demand for energy continues to grow, the operational stability of power facilities becomes increasingly important. Insulation materials in power cables play a vital role in preventing electrical faults, short circuits, and leakage. However, over time, these materials deteriorate due to factors such as temperature fluctuations, mechanical stress, environmental conditions, and electrical stress, leading to a decline in insulation performance. This deterioration increases the risk of power system failures, potentially causing outages, equipment damage, and significant repair costs. Therefore, early detection of insulation aging is essential to ensure the safe operation of the power grid[1]. This paper focuses on the insulation resistance (IR) test method, which is one of the most straightforward and practical techniques for assessing the insulation condition of cables in the field. The primary objective is to determine the insulation resistance of individual cable segments and joints based on the overall insulation resistance measurement, allowing for the evaluation of the aging status of each segment. By developing a mathematical model that accounts for the aging characteristics of cables, this study proposes a method to calculate the insulation resistance of each cable segment from the overall insulation resistance data[2][3]. The model considers the service time of each cable segment and the changes in electrical characteristics during the aging process, enabling accurate data analysis to deduce the insulation resistance values of individual segments. The proposed method involves establishing an equivalent circuit model for the cable system, where each cable segment and joint is represented by its insulation resistance. The model assumes that the insulation resistance of each segment and joint decays exponentially over time, influenced by factors such as electrical load, temperature, and humidity. By applying this model to real-world data from the Singapore power grid, the study demonstrates the feasibility and accuracy of the method in practical applications[4][5]. The results show that the calculated insulation resistance values for cable joints closely match theoretical values, while the values for cable segments exhibit acceptable deviations. Furthermore, the paper explores the relationship between insulation resistance and conductance, proposing a conductivity-based model to enhance the accuracy of the calculations. The study also highlights the limitations of using simple exponential functions to model cable aging, as they may not fully capture the multi-stage aging processes or the influence of external factors such as temperature and humidity. To address these limitations, future research directions are suggested, including the development of more complex models that incorporate multiple aging mechanisms and environmental factors. In conclusion, this research provides a robust framework for assessing the insulation aging of distribution cables, offering a practical and accurate method for determining the insulation resistance of individual cable segments and joints. The findings have significant implications for the maintenance and management of power grids, enabling timely detection of aging issues and reducing the risk of power system failures[6]. Future work will focus on refining the mathematical models, exploring advanced detection technologies, and integrating machine learning algorithms to further enhance the accuracy and reliability of insulation resistance measurements.