| With the development of new type of relay equipment especially of the protection based on microprocessor, there are more requirements on the technology of measure and test, and also more requirements on relay tester. The wrong actions on relay equipments due to the quality of relay equipments, occupying above 60%. The relay tester is an important device, because it must use it to design, product, measure and test the relay protection equipments, the quality of relay protection equipment is based on the quality of relay tester.This paper will discuss how to design a relay tester with DSP and high speed DA converter, it accords the people's input current and voltage, the program can control the circuit and DA converter to output three phases current and voltages, and send to the relay protection devices, at the same time check the feedback information of relay protection devices, and give some responses according these information. It can output 12 analog signals, input 24 digital signals and output 24 digital signals. The basis analog signals are: sine wave form, triangle wave form, square wave form and user's define wave form, and the same time it fully used the high process capability of DSP to generate the special order of harmonic wave form. It can output high accurate signals even if the signal's frequency is 1kHz and it can also output high accurate small signals.In this paper, it discuss the hardware design and software design of the system. In hardware design, it mainly includes peripheral memory, low Butterworth filter, isolated serial port. Software includes boot loader routine, main routine, communication routine and algorithm of linear method of interpolation routine.In this design, it fully used the high process capability of DSP and high speed and accurate DA converter, the system can output high accurate signal, from the result of actual measurement, it conform to the county standard. So it can be used to design, product, measure and test the relay protection equipments. |
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