Research and Improvement of Fourier Algorithm in the Microcomputer Relay Protection

Abstract:

Fourier algorithm can be effective utilized in the Microcomputer relay protection to filter out Harmonic component in the AC signal .but the drawback is that not filter attenuation DC component. it may be affect the computation accuracy of the entire system .and it is also reduce the efficiency of the system. In this paper ,we combined with the actual project ,on the basis of analysis of the full-wave Fourier algorithm ,for the problem of it can not filter decaying a periodic component ,we proposed an improved algorithm, and combined with MATLAB simulation ,the results show that the improved algorithm has the advantages of high accuracy and the algorithm is simple. In the microcomputer relay protection of the power system need to handle all kinds of signals, provide the necessary information for the implementation of protection. however, With the rapid development of computer technology and the continuous research of computer algorithms, a lot of actual power system protection device has been widely used in our life, on the one hand, these devices reduce the complexity of building hardware circuit, on the other hand ,it can make full use of the filter function about some algorithms have itself. The most important is that it can avoid the problem of instability and low efficiency with some filter circuit. But, this characteristic need the algorithms has a high precision ^[2,3]. The algorithm is set up in the microcomputer protection is a mathematical model for achieve some specific function. and write the corresponding computer applications according to this model. Then do some specific mathematical operations with these digital signals will achieve the purpose of protection. At present, the widely used full wave Fourier algorithm has a function of filtering DC component and harmonic component^[4],but it can not filtering the decaying DC component in the system. It will be cause a certain interference and influence to the whole system in the practical application, the result is that led to the precision of the operation drop and lose the meaning of the protecting. In this paper, combined with specific engineering example give an improved calculation method. Through example of simulation has proved that using this algorithm can accurately figure out fundamental component and harmonic component, and it has the advantage of algorithm simple and high accuracy ^[5].

• Periodical: Applied Mechanics and Materials (Volumes 347-350)
• Pages: 1945-1948
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.347-350.1945
• Online since: August 2013
• Authors: Jian Xu, Xin Yao
• Keywords: AC Signal, DC Component, Fourier Algorithm, MATLAB, Microcomputer Relay Protection

References

[1] baohui Zhang, xianggen Yin. Power system relay protection [M]. China Electric Power press, 2005, pp.256-273.

[2] chengxue Zhang, shuwen Ding. A fast algorithm of microcomputer protection in the AC sampling. [J]. Journal of electric power system and its automation, 2000, 12(1), pp.24-27.

[3] kemi Qian, changqin Li. The comprehensive research of the algorithm in the microcomputer protection of Electric power system. [J]. Nanjing: Electric power automation equipment, 2005, 25(5) pp.43-45.

[4] jin Gao, jianyong Zhen, zhengdon Pan. The comprehensive research of the improved Fourier algorithm in the microcomputer protection of Electric power system. [J]. xuchang : relay, 2002, 30(10) pp.16-20.

[5] zhijin Zhang, hanzhong Wang. The improved of the Fourier algorithm and the differential equation algorithm. [J]. Automation of electric power systems, 2009, (5), pp.20-30.

[6] qinxin Zhao, zhiqiang Gu. Study of microcomputer protection algorithm[J]. Modern manufacturing technology and equipment, 2006, 11(5) , pp.68-71.

[7] xinhong Zhao, huili Zhang, hong. Yuan. Microcomputer protection technology[M]. Beijing: Chemical industry press, 2009, 12(8), pp.75-81.

[8] peiqin Chen. Digital signal processing course（the second edition）[M]. beijing : Tsinghua university press, 2001, 21(9) , pp.52-58.