566 / 2022-03-30 10:39:22

Study on the Degradation Evolution of GIS O-rings Under Multi-factor Accelerated Aging Test

seal ring,leakage rate,compression set,multi-factor accelerated aging,failure criterion

O-ring is the key part of SF₆ gas seal for GIS equipment, and the multi-factor accelerated aging test is an important method to study the evolution of the mechanical properties and leakage rate with aging time. In this paper, the three-factor accelerated aging test of thermal, compression, and pressured SF₆ (TCS), as well as the traditional two-factor accelerated aging test of thermal and compression (TC) were performed on the GIS seal ring samples. The aging temperatures were 90 ℃, 105 ℃ and 120 ℃, and the compression rates were 20%, 25%, 30%. The test device was filled with 0.3 MPa SF₆ gas, and the aging time ranged from 0 to 122 days. After the aging, the compression set (CS) and leakage rate were tested. The test results showed that the evolution of CS under TCS could be modelled by exponential functions, and the degradation rate was slower than that of TC. The leakage rate of the GIS seal ring under TCS first decreased and then increased, but no leakage failure occurred. However, after 88 days of TC, 4 samples failed. The correlation between CS and leakage rate was established, and the failure criterion of the GIS seal ring was obtained as the CS reached 74.1%.