500kV High-capacity Single-phase Generator Transformer Research Of Technology

DFP-400000/500 is a oil-immersed, single-phase, forced-directed oil and forced air cooling, and no excitation regulating transformer. The transformer has a large single column capacity, large magnetic flux leakage, and high voltage levels. In order to improve the safety and reliability of overall operation of the transformer, at the design of the main and longitudinal insulation products, combined with computer simulation data validation, fully considering the induction, impact and other harsh conditions, the potential gradient of the winding and the insulation margin, Take the appropriate technical means on the way of end insulation winding terminal, the require of winding terminal's shield and wrapping, measures of shielding disk etc. According to experience in the early stage of the design on the basis of the optimal design parameters,this produc improves the design structure, parallel structure, the proposed two column column two high voltage coil in parallel, low voltage coils in parallel, two same column capacity distribution, each column capacity is 200 MVA, it can reduce the body end magnetic flux leakage, arrange conveniently at the same time, two column coil ampere-turns balance ability. Magnetic flux leakage of Winding overhang is far higher than that of conventional products, in order to achieve the ideal shielding effect, we use the computer simulation software to calculate the distribution of magnetic flux leakage inside the transformer. After leakage magnetic field is controlled, supplemented by a reasonable oil distribution, according to the calculation result to determine the oil flow path, making the transformer local overheating and temperature rise problem has been effectively resolved. In the anti-short-circuit capacity of the product, combined with electromagnetic calculation and simulation calculation, select a reasonable yield strength of electro-magnetic wire, low voltage winding use self-adhesive transposition wire, and wrapped with a hard paper cylinder. Accoding to the calculation results, reasonably determine the distribution of ampere-turn,adjust the application of various kinds of shielding measures,solved the leakage magnetic field and other problems effectively, then the product has significant advantages such as low loss, low partial discharge and low temperature rise.