The Research And Design On Micro-computerized Protection Device For Transformer

Power transformer is the hub equipment which connects grid and exchanges power. Its safety and stability directly relates to the continuous operation of the entire power grid. Transformer micro-computer protection device provides a great guarantee for the safe operation of the transformer in the power system. With the expansion of power transformer capacity and power grid in recent years, the research and design of transformer micro-computer protection device attract great attention.In the background of the research and development of transformer protection, this paper analyzes the principles of transformer differential protection, ratio differential protection and excitation inrush. At the same time, multiple voltages over current protection, zero sequence protection, overload protection, TA break and TA saturation are also introduced based on design tasks and demands. On these basises, this paper also proceeds the Matlab simulations of excitation inrush current and ratio differential protection and analyzes the result of simulations.Based on the theory and simulation, the hardware and software of transformer micro-computer protection device are designed. The hardware adopts the design method of dual CPU. The DSP chip TMS320F2812 realizes the function of protection and C8051F020 chip realizes the function of management. Dual CPU not only speeds up the operation speed of the device, but also increases the safety and stability of the device. The hardware mainly includes sampling circuit, filter amplifier circuit, multiplex circuit, frequency measurement circuit, switching input and output circuits and communication circuits. On the software DSP uses C/OS-II multitasks and real-time operating system. Its tasks are mainly divided into four modules, namely, measure task, the protection of judgment task, sampling, A/D conversion task and communication task.Finally, the transformer micro-computer protection device is tested. The test mainly analyzes the methods of the test and results of the test. This paper has certain reference value for the research and design of transformer micro-computer protection.