Multi-Parameter Detection of Defects in HV Cable Buffer Layer Based on Gas, Temperature, and Pressure

High voltage cable is an important part of the power system. Water ingress into the buffer layer and poor contact with the aluminum sheath in high voltage cables can cause ablation defects and local overheating. Power accidents due to buffer layer ablation have occurred frequently in recent years. However, there is a lack of effective diagnostic methods for buffer layer ablation defects. To address the above problems, a multi-parameter detection method for ablation defects in the buffer layer of high-voltage cables based on gas, temperature, and pressure analysis is proposed. The volume fraction, temperature, and pressure of the characteristic gases C<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>H<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</inf>, C<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>H<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf>, CO, and H<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> are used as the characteristic parameters to characterize the ablation defects of the buffer layer. Infrared spectroscopy was used to analyze the volume fraction of the characteristic gases, a thermocouple sensor was used to measure the temperature, and a piezoelectric sensor was used to measure the pressure. Simulated ablation analysis experiments and actual cable detection verified the method's validity. The results show that with the increase of ablation time, the characteristic gas volume fraction, temperature, and pressure all show an increasing trend. The characteristic gas volume fraction, temperature and pressure in the buffer layer of high-voltage cables with ablation defects in the field are higher than those without ablation. The characteristic gases, temperature, and pressure can be used to characterize the buffer layer ablation defects and to diagnose these defects. It is expected to be a new diagnostic method for buffer layer ablation defects in high voltage cables. It can support the early warning of power accidents and improve the safety of high-voltage cable operation.