EXPERIMENTAL STUDY OF THE EVAPORATIVE COOLING SYSTEM IN A LOW-NOISE POWER TRANSFORMER

Decades of experience in underground substations indicated that the traditional cooling technologies have their own various shortcomings. Therefore, a novel evaporative cooling system was pointed out and will be applied in a power transformer of an urban substation. This new cooling technology could be considered as a two-step cooling system, which could transport heat energy effectively from underground thermal sources to the parallel finned tubes assembled in the transformer tank, and the evaporative coolant in parallel finned tubes absorbs heat and changes from liquid into vapor, then the vapor condenses back into liquid in the radiators on the ground. Furthermore, the cooling system is self-circulated, needing no additional pump or fans. A 2500W experimental model is designed, fabricated and tested, and the testing result shows that the top oil temperature rise meet the requirement of Chinese National Standard of GB 1094.2-1996 and the relevant IEC 60076-2-2011, which proves the feasibility of the new transformer cooling technology. Next, a transformer prototype will be fabricated and put into operation.