Experimental and numerical investigation of wicked heat pipe cooling efficacy in oil-immersed transformers

Abstract

The significance of thermal management in transformers, recognized as a pivotal component within the electricity industry, has prompted numerous studies in this area. Although various methods to decrease hot-spot temperatures in transformers have been introduced, a comprehensive investigation into the effectiveness of wicked heat pipes (WHPs) remains lacking.This study aims to rectify this deficiency by conducting experimental and numerical investigations to assess the impact of WHPs on transformer thermal management. Firstly, the WHPs undergo testing with varied thermal loads to assess their heat transfer efficiency in steady-state operation. This not only monitors the WHP conditions to prevent limitations but also computes the effective thermal conductivity for numerical study input. Next, the thermal management performance of a laboratory transformer with two WHPs was experimentally studied both indoors and outdoors.Additionally, the simultaneous utilization of WHPs and radiator with various configurations is examined experimentally to assess their combined effect. Then, a numerical study investigates how the number of WHPs influences the reduction of the hot-spot temperatures in the transformer. The experimental findings indicate that the use of WHPs led to a 9 % reduction in peak transformer temperature under real conditions. Simultaneous use of the radiator and WHPs, regardless of their arrangement, resulted in an approximate 18 % reduction in the hot-spot temperature. Additionally, numerical simulations suggest that employing eight heat pipes could reduce hot-spot temperatures by up to 9.2 °C, representing a 15 % improvement compared to baseline conditions.