The Study On The Grid Harmonic Control And Reactive Compensation Technology

At present, power electronics technology is widely used in the power grid due to itsrapid development,which also leads to large number of harmonics in the grid.It causes alot of pollution and at the same time consumes a large amount of reactive power,whichcauses serious harm to the electricity system and the users. Active power filter has beenput more attention in recent years because it has good dynamic performance andreal-time and also can compensate the harmonic and reactive current,.In this paper, harmonics and reactive power compensation of three-phase four-wirepower system are its starting points to solve the problems of increasingly seriousharmonic pollution and the increase of reactive power in three-phase four-wire powersystem. First,it introduces the working principle and classification of a shunt active thefilter, and establishes a corresponding mathematical model. Secondly,it sketches theharmonic current detecting method based on instantaneous reactive power theory andthen proposes an improved p-q method.Based on the theoretical analysis and simulationcomparison,it proves this method that can detect the harmonic and reactive currenttimely and accurately.Finally, this paper chooses the voltage space vector controlmethod based on coordinate transformation by the comparison and the study aboutvarious compensation current control methods.On the basis of the above-mentioned research, this paper designs a set of parallelactive filter system which can be used in three phase four wire system power system.This paper uses TI’s DSP chip TM320F2812as the control core in the control circuit ofthis system and the experimental circuit design and software flow chart of the main partin this system are given. Finally, the simulation modeling of entire system is carried byMTALAB7.0,and the simulation results have the desired effect.