| The relay protection is an important component of the power system, and it plays an important role in the power system security. Relay protection can monitor and protect the real-time possible malfunctions of electrical equipments such as generator, transformer, electric line and so on. With the rapid progress of electronic technology, computer technology microcomputer relay protection device is used widely for its unique advantages. According to the characteristics of microcomputer relay protection and insufficient of microcomputer protection device, this paper researches and designs an experiment platform which is composed of simulated loop power system and virtual instrument technology. Through the modular function design, it can express internal action logics, the principle of microcomputer relay protection and the working processes and so on clearly.This paper includes two parts, which are the construction of simulated platform and the design of functional programming. The platform is mainly composed of simulated power system and data acquisition system. Simulated power system mainly refers to the typical structure of actual power system, this paper designs a simulated loop power system experiment platform with laboratory scale and lumped parameters. The platform has the function of simulating the short circuit according to different types of short circuit and different positions of short circuit point. The main function of data acquisition part is completing the communication between the measured electrical parameter and industrial computer, which includes signal collection, signal conversion, signal processing and signal transmission. Functional programming consists of algorithm of microcomputer protection the starting module, selection module of fault phase, action module of protection and the module of turbulence closure. This paper studies the algorithm of microcomputer protection, and improves the Fourier algorithm aiming at reducing the influence of decaying DC component and overcoming the shortages of traditional Fourier algorithm. The improved algorithm is verified by Matlab. The simulation results show that the improved algorithm can reduce the influence of decaying DC component and the algorithm has practical value. At last the short circuit experiments of experiment platform prove that the experiment platform implements the designed request. |
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