The Analysis And Design Of The Power Quality Monitoring Equipment

As more and more electronic equipments are connected to the electrical grid, the problem of harmonics in electric power system has become worse, which affects the quality of power supply seriously.The active power filter is an effective method to restrain harmonics in power grid. For the active power filter, the accuracy of harmonic detection is an important prerequisite to insure the good compensation performance. This paper reviews the analysis of current methods of harmonic current detection, chooses harmonic current detection algorithm based on instantaneous reactive power theory, and mainly focuses on the ip ?iq algorithm, its theoretical analysis and simulation analysis. This paper deeply studies various SPLL theories that applied to the link of harmonic detection, their advantages and disadvantages. Furthermore, it proposes a new type of SPLL based on DSC module and its simulation analysis. According to the example of the ip ?iq algorithm of the SPLL based on synchronization reference frame, it discussed in deep how low pass filter in harmonic detection link affects the results of harmonic detection, and proposed the new LPF sliding window based on definite integral and conduct simulation analysis. According to the example of the synchronization reference coordinate system to the SPLL and ip iq? method, it discussed in deep how low pass filter in harmonic detection link affects the results of harmonic detection, and proposed a new sliding window LPF based on definite integral and simulation analysis. At last, this paper introduces the experimental platform of four bridge arm parallel active power filter, carries out the DSP programming realization of harmonic detection links and shows the experimental results. The simulation and experimental results show that the new three-phase SPLL has good performance based on the DSC module. The distortion rate of the three-phase fundamental positive sequence current, which is detected by the harmonic, is low. The three-phase balance is good, which could effectively constrain the voltage distortion and frequency fluctuations. On the basis of definite integral, the new sliding window LPF has a relatively good filtering effect and half a fixed period of dynamic response.