A Novel Condition Assessment Method for Corrugated Aluminum Sheathed XLPE Cables Based on Evolved Gas Analysis

Condition assessment is significant to the maintenance management of high-voltage (HV) cross-linked polyethylene (XLPE) power cables. This article presents a condition assessment method for corrugated aluminum sheathed cables based on evolved gas analysis (EGA). First, simultaneous thermogravimetric (TG) and mass spectrometric analyses of the pyrolysis of each cable material were conducted to characterize the gas generation caused by thermal faults. Simulated experiments were designed to investigate gas generation caused by electrical faults. The results show that different cable faults (low- and high-temperature pyrolysis of semiconductors, insulation, and buffer materials; low and high energy discharge activity across insulation materials and electrochemical corrosion of the buffer material) show distinct gas generation characteristics. Based on the evolved gases, a method of identifying faults from the key gas concentration is proposed in this study. Moreover, gas transport within the corrugated aluminum sheathed cable with a buffer layer was analyzed, based on which a gas sampling method for cables with a buffer layer is proposed. Finally, the developed method was validated by practical applications. The proposed method is comparable to conducting a blood test on a human body in that it can help discover various incipient cable faults. The fundamentals and data interpretation methods are adaptable to all XLPE cables.