A novel method to monitor the condition of fluid-filled taped cables employed in underground transmission through dissolved-gas-analysis

There is an increasing interest to reliably monitor the condition of installed high voltage fluid-filled taped (FFT) transmission cables and accessories. The traditional methods such as the dissipation factor and dielectric breakdown of cable fluid do not lead to satisfactory results. The dissolved-gas analysis (DGA) technique that has been successfully applied to power transformers holds great promise for fluid-filled taped cable systems. This paper describes a novel method specifically developed to apply the emerging DGA technique to such cables. It is named EPOSS which stands for EPRI (Electric Power Research Institute) pressurized oil sampling system, as it has been developed under EPRI sponsorship. This method, which is based on head-space analysis, is characterized by a unique fluid sampling system, a relatively simple approach and a fully automated gas analysis system. This method has been extensively applied to both laboratory and field conditions With great success. Unlike the conventional transformer DGA method, a large number of dissolved gases are considered in this novel method.