The Study Of DSP-Based Harmonic Measurement

With the development of power electronic technology, more and more non-linear devices are applied to the power system. Power network harmonic pollution is increasing. So the security of power system is threatened. The operating loss is increasing. The user's normal work is affected. Therefore, anglicizing and monitoring power system harmonics is very useful to make sure power system running safely.The traditional power quality anglicizing and monitoring systems generally use MCU as code, but an MCU is not fast enough to sample highly and real-time analysis. So the sample data is not enough, and the accuracy of data is low. In recent years, digital signal processor (DSP) is used, so that high-speed sampling, high-speed data storaging and real-time processing of data can be finished perfectly. The DSP uses advanced Harvard architecture. The program memory and data storage has their own bus. It can process program and data at the same time. So it greatly improves the accuracy of harmonic anglicizing. With the method of anglicizing harmonic and electronics developing, more and more harmonic anglicizing equipment is used. Harmonic anglicizing equipments made in abroad are powerful, high precision but expensive. Harmonic anglicizing equipments made at home is opposite. The subject introduces a harmonic anglicizing equipment based on high-speed DSP and FFT, which is high-speed, powerful and cheap.Firstly, variety of harmonic anglicizing algorithm is compared in the subject. The FFT is choosed and studied deeply. Windows and interpolation is used to improve FFT. Secondly, appropriate electronic components are choosed to design a harmonic anglicizing equipment. The paper introduces the hardware of harmonic anglicizing equipment that includes sample module, harmonic anglicizing module, man-machine interface module and serial interface module, etc. Thirdly, the software of harmonic anglicizing equipment is designed, which includes program of sampling data, processing data, communication and upper monitor, etc. Finally, the harmonic anglicizing equipment is used to anglicize harmonic that produced by another equipment. The paper introduces reason of anglicizing error and the way of reduced error is introduced. The result achieves the desired results. The final result is as good as expected.The anglicizing result indicates that the harmonic anglicizing equipment based on DSP is high-speed and high-accuracy. It can be used in power system.