Research Of Harmonic Current Detection Method Based On Instantaneous Reactive Power Theory In STATCOM

With the improvement of the people's living standards, the requirements of the powerquality are also increasing. Due to the nonlinear loads widely used in the grid, the harmonicpower contained in the grid gets higher than before, and the electrical harmonic pollutionbecomes more serious, mostly because non-linear components can generate the harmonicdistortion of current and flow in the grid, the impedance of electricity grid system may causethe distortion of the voltage and then effect the other loads, which directly result in poorpower quality and contradict the high power quality that people required. STATCOM (staticcompensator ) is one of the most effective devices resolving this contradiction , which can notonly compensate the reactive power, but also eliminate harmonics. STATCOM in eliminatingharmonic is analyzed in this paper as a breakthrough point, it has so many advantagescompared to the passive filter, which is functionally equivalent to the active power filter.Harmonic current detection technology is one of the most critical technologies of STATCOM.The development of harmonic current detection technology directly effects the developmentof STATCOM technology. In order to improve the property of STATCOM, it is verysignificant to improve the harmonic current detection technology.This paper introduces different methods of the harmonic current detection and analyzestheir advantages and disadvantages. Its focus on detailed analysis of the instantaneousreactive power theory based on the harmonic current detection method, and the simulationverify its correct. Phase-locked loop which is one of the most critical technologies for thecurrent detection has been designed, and the simulation and experiment have been expected.The difficulty of the current detection is the design of digital low-pass filter which directlyaffects the rapid and accurate of the harmonic current detection. It has designed a kind ofdigital low-pass filter which meets the requirements of the current detection, and the results ofsimulation in the MATLAB / SIMULINK prove that the design is correct and effective.