Internal Fault Simulation Of Power Transformer And Research On Its Protection

The application of large-size transformer and extra-high voltage long distance transmission line worsens the working environment of transformer protections, which results in that the correct operation ratio of the present protection is low, so the transformer protections need improvements. In order to develop new protection criteria, the voltages and currents during faults must be studied. In the paper the liner model in ATP is adopted to study transformer internal faults. At present during calculation of the parameters many important factors are ignored, in the paper the improved method to calculate the parameters of transformer model is presented, the calculation precision is improved which is verified by the results of simulations. The interface to run simulation program is designed. In the last period, some new transformer protection schemes including power differential method are studied, and the improved method based power during half of one period. Results of study indicate that transformer faults can be checked out effectively through using these schemes.