Research On Inner Flow Filed Distribution Numerical Value Of Cast Resin Dry-type Marine Transformers

China’s shipbuilding industry developed rapidly and the total number and tonnage of ship have greatly improved as the continuous development of comprehensive national strength. The dry-type transformer, with the advantages of excellent safety performance, simple structure and easy to be maintained, has been widely used on board. Due to the increasing capacity, the cooling of dry-type transformer once became the key factor that hindering its development. The research on transformer inner flow situation, changing the cooling structure and improvement of the cooling performance is quite meaningful.This article, which studied and compared based on experimental result between a prototype of 250 KVA dry-type power transformer and the reasonable 3D Model established by Gambit software, calculated flow field and temperature distribution in transformer tank, and compared with the experimental results, proved the feasibility of the model.The comparison experiment between the six typical exit positions and transformer real working condition was designed, both heavy load and rated load conditions were done on six positions. The simulation results show:The flow conditions were similar when the loads were 250 KVA and 375 KVA, the highest temperature of winding appeared in low voltage part. The highest temperature gradually reduced from Position 1 to Position 7 and then it gradually rise, the lowest value all appeared on Position 4. The highest temperature point appeared on Position 1, that was when the worst heat dissipation condition was 375 KVA, the highest temperature differences between Position 1 and Position 4 was 12 K, the temperature rise reduced 13.5%. When the condition was 250 KVA, the temperature rise reduced 18.4%. It explained the changes of entrance and exit positions for different power have an effect on highest temperature reduction, and necessarily, it was obvious when heavy load. It was excellent when the exit position is 4, it located on the upside of opposite of transformer entrance, so the exit position should be located to the greatest extent of entrance and higher. The temperature difference was low on Position 3 and 5, the heat dissipation condition were next to Position 4.It was a research on 14 working conditions as adding baffle in inner transformer. After added, it had an obvious effect on winding heat dissipation, the high and low voltage winding temperature both reduced, especially, low voltage winding temperature decreasing amplitude is larger. The highest temperature did not appear on low voltage winding position, and the highest decreasing amplitude could be 70.8%, the high voltage winding temperature decreasing amplitude was 42.6%. It was excellent when the baffle located winding height on 48.8%-58.3% sections and economic reasonable on 48.8%-75% as well.