Study On The System Used For Voltage Ratio Measurement Of Special Transformer

It is well known that the transformer is one of the most important equipments in traction substation and its operation condition greatly influences the safety of traction power supply system. Therefore it is very effective to get the operational parameters of transformer by kinds of testing methods and reduce the disk of expensive failures caused by transformer.In China the traction power supply system adopts single-phase AC. In AT power supply system some transformers with special connection mode, such as Scott transformer, Anti-Scott transformer, balance transformer and so on, are usual used.The voltage ratio is one of 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 winding short. The deterioration of voltage ratio may result in damage of transformer, which may also lead to the failures of power supply system. Therefore it is valuable to study on the method for measuring voltage ratio of special transformer. Since these transformers have special connection mode, the apparatus used for common transformer cannot directly measure the voltage ratio. It is very necessary to develop a novel apparatus especially used for these special transformers.In this thesis, a novel voltage ratio measuring system for special transformer is introduced. The principle and design realization of the system is discussed in detail, including the whole structure, the principles of main modules, and the design of the hardware and software. In the end, the performances of the whole device are tested and the errors are analyzed. The microprocessor ATMEL AT89C55 is adopted as the center of the system, and the system is based on the design idea of system-on-a-chip.