The effect of pressure loss in high-pressure gas-filled cables

High-pressure gas-filled (HPGF) cables normally are pressurized with 200 psi of nitrogen. The cable system is equipped with pressure sensors to encounter any pressure loss. However, often these sensors failed in service and if a pressure loss occurs, it only can be discovered during routine inspection, which could be a few months apart. This paper investigates the effect of losing pressure on the ionization level of the cable. Partial discharge (PD) measurement was used to check the ionization level. The lower pressure limit traditionally is established by conducting power-factor measurements. This pressure limit is re-examined by conducting PD testing in contrast to the power-factor measurements. With PD testing, a more accurate level is established. The load-cycling effect during a prolonged pressure loss was also investigated