It is suitable for oil-insulated power transformers with AC 50Hz, primary side rated voltage of 10kV, rated through-current of 50A and less, and rated capacity of 630 KVA and less. It is directly connected with the transformer tank cover, which greatly reduces the transformer volume occupied by itself. Shares the oil chamber of the transformer, because it adopts vacuum arc removal, the transformer oil, overcomes the disadvantages of the transformer oil inside it after a long-term, and truly achieve safe, reliable, maintenance-free and other characteristics. Final users shall choose the corresponding supporting on-load voltage regulating controller of our factory, as the operation control mechanism, which can realize automatic, manual and wireless adjustment, and truly realize automatic intelligent adjustment.