A Promising De-ionized Water Cooling Based ERIP Bushing-II: Cooling Mechanism and Effect of Parameters

Overheating has become a key factor that threatens the safe operation of the epoxy resin impregnated paper (ERIP) HVDC bushing and restricts its engineering application. The de-ionized water cooling based ERIP (DIWC-ERIP) bushing utilizes diffusion and convective heat transport to achieve low temperature distribution in the DIWC-ERIP bushing. In this manuscript, the temperature, heat flux density and the heat flux distribution of the DIWC-ERIP bushing are analyzed and the cooling mechanism is discussed. The heat flux density in the current carrying conductor (CCC) is mainly in axial direction. In the ERIP it is mainly in negative radial direction in oil tank side, and in positive radial direction in flange area and air box side of the bushing. The effect of the flow rate and temperature at inlet of de-ionized water on the temperature distribution of the bushing is studied by experiments and simulations, and the simulation results are very close to the measured results. The parameters of the thermal resistance per unit length of the thermal thin layer and the radii of water tubes have little effect on the temperature distribution of the bushing. The temperature distribution of the bushing can be controlled by the temperature of water at the inlet. Due to the strong heat dissipation capacity of de-ionized water, as the flow rate is 2 L/min, the maximum temperature of the ERIP doesn't exceed 120 ℃.