Research On Background Harmonic Voltage Damping In Power Systems Based On Hybrid Active Power Filter

Along with the development of power electronics,a variety of power electronic equipment is widely used in the power system,which improves people’s living standard,so does the harmonic pollution become more severe than before.The resonance between line inductances and line capacitors and power capacitors installed for power factor correction may cause the harmonic propagation.Inorder to solve this problem in the radial transmission line, this paper proposed an site selection strategy of single-frequency tuned R-HAPF which can be used to the radial transmission line for the background harmonic damping.Firstly,this paper studies the source and propagation characteristics of the background harmonic,and research status of harmonic damping strategies.Then the distributed-parameter model and the lumped-parameter model of the radial line are set up.At the same time, some theoretical derivations are made for the causes of the harmonic voltage amplification based on the radial transmission line.Secondly,according to the distributed-parameter model, the causes of the background harmonic proliferation or amplification in radial line are analysed.The principle of harmonic suppression scheme R-APF which is installed on the end bus of the feeder is introduced.Both theory and simulation results clarify that installation of the APF based on grid current detection on the end bus of the feeder can suppress harmonic propagation,but it results the ‘whack a mole’phenomenon.Thirdly,in order to solve ‘whack a mole’ phenomenon caused by the harmonic suppression scheme R-APF which is installed on the end bus of the feeder, the transmission line theory is used to analyze the harmonic voltage propagation caused by the background harmonic voltage in power systems. Also,the parallel-hybrid APF(HAPF)harmonic compensation principle and calculation of the capacity of the source part are studied.A new discrete frequency of R-HAPF site slection strategy is proposed to damp the background harmonic voltage propagation in power systems.Both theory and simulation results verify the effectiveness of this harmonic damping strategy in terms of compensating the grid harmonic voltage.Finaly,according to the lumped parameter model of the radial transmission line, the9 km transmission line has been built imitatively.Experiments platform based on TMS320F2812 DSP and HAPF have been set up.Experiments have been performed to demonstrate and verify the effectiveness of the proposed strategies.