Study On Testing Method For Voltage Ratio Of Transformer With Special Winding Mode

The power quality is highly concerned by the consumer, with deeper innovation in electric power market. How to use the electric power equipment in the configuration and its mode-choosing to eliminate or suppress the harmonics, to improve the power system stability and the power quality, is the important study subject of electrical engineering. It is well known that transformer is one of the main equipments in the power system. It takes the important task of transmission and distribution of electrical power. How to use transformer to improve the stability of power system and the power quality is concerned. Now some transformers with special connected mode of winding are applied in the electrical engineering. Some zigzag transformer are used to improve the power quality when we renovate our the power grid in the cities and the country, and the three-phase to two-phase transformer, such as Scott transformer and Kubler transformer, are used to substitute for the three-phase to three-phase transformer in the railway traction substation of the power supply systemThe quality of transformer itself directly influences the reliability and security of the power system, and its operation condition greatly influences the power system security. Therefore it is very effective to get the operational parameters of transformer by kinds of testing methods and reduce the risk of expensive failures caused by transformer. The voltage ratio is one important parameters of transformer. It relates to the status of transformer winding. The variety of voltage ratio reacts to not only the insulation status of transformer winding but also the fault of the winding short. The deterioration of voltage ratio may result in damage of transformer, which may also lead to the failures of the power supply system. Since these transformers mentioned above have special connection mode, the apparatus used for common transformer can't directly measure the voltage ratio. It is very necessary to develop a novel apparatus especially used for these special transformers.In the thesis, the existing testing methods are compared. Based on the method using single-phase voltage source, the configuration and electromagnetism of the three kinds of transformer mentioned above are analysed, and their testing models of the voltage ratio are discussed and presented respectively. The hardware and software of the testing apparatus of the voltage ratio, based on the models and the multi-function platform for transformer testing, are introduced.