A Promising De-Ionized Water Cooling Based ERIP Bushing-I: Model Validation and High Cooling Efficiency of the Cooling Method

Overheating has become a key factor that threatens the safe operation of the epoxy resin impregnated paper (ERIP) high voltage direct current bushing and restricts its engineering application in high current field. In this paper, a new method based on cooling of de-ionized water is proposed to resolve this problem. A prototype of the de-ionized water cooling based ERIP (DIWC-ERIP) bushing of rated voltage ±400 kV is designed and built. The temperature distribution on the surface of the current carrying conductor (CCC) is measured under RMS AC currents of 4500 A and 6736 A. The simulation model of doubly coupled electro-thermal-fluid field is built, and the temperature distribution is simulated on the surface of the CCC for the prototype of the DIWC-ERIP bushing. Comparing the simulation results of temperature distribution with the experimental results, the simulation model is verified. Compared with other four cooling schemes of the conventional unmodified ERIP scheme, the material based BN modified ERIP scheme, the double-conductor cooling scheme and the oil cooling scheme, the hotspot temperatures are decreased at least 43.4 °C, 11.5 °C, 46.3 °C and 58.4 °C under the current of 4500 A, respectively. The results show that the cooling effect of de-ionized water is more obvious and the new DIWC-ERIP bushing has better heat distribution characteristics. The proposed bushing may resolve overheating issues in the ERIP at valve side of converter transformer in high current application.