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Research On Principle And Method Of Comprehensive Compensation Of Harmonics And Reactive Power For Distribution Network

Posted on:2008-06-26Degree:MasterType:Thesis
Country:ChinaCandidate:F J PanFull Text:PDF
GTID:2132360215480212Subject:Electrical engineering
Abstract/Summary:PDF Full Text Request
Static Var Compensator (SVC) based on Thyristor Controlled Reactor(TCR) has good compensation-performance for rapid changing load, so it has become a hotspot in recent year. In practical application, The TCR is used to work in parallel with the Fixed Capacitor. Hence, TCR not only can absorb inductive reactive power, but also can absorb the capacitive reactive power. The TCR itself introduces harmonic currents when in operation, the harmonic current could bring hazard to power system. Hence, the filters are often set up with TCR to eliminate the characteristic harmonic current of the TCR. In this paper, the working principle and control means on TCR is searched, especially for the single-phase TCR and 6-pluse TCR's characteristic harmonic. This paper has founded single-phase and 6-pluse TCR's model by means of MATLAB/Simulink and has analysed the relation of the Thyristor's trigger angle, trigger pulse and fundamental current.The principium of passive filter(PF) and active power filter(APF) is introduced in detail. Hybrid active power filter(HAPF), which combines APF with PF to decrease the capacity of inverter for reducing the cost of APF, is presented by some researchers. HAPF overcomes the shortages of PF and APF, and will be popular in future.Exact and real-time detection of the instantaneous variable harmonic and reactive current in power system is the premise for compensation of all kind of compensator, the method based on instantaneous reactive power theory is used widely in tri-phase system than others, and it consists of p-q detection method applied to symmetry power system without distortion, i_p—i_q detection method applied to asymmetry distortion power system. By means of MATLAB simulated and analysed, we verified this two kinds method have been able to check the harmonic and reactive current component from distorted current.A scheme of comprehensive compensation of reactive current and harmonic combined with TCR and HAPF is described in this paper for substations in tri-phase power system. The TCR together with the passive filter part of the HAPF makes a static Var compensator (SVC) for load balancing and power factor correction. The active filter is used to improve filtering characteristics of the passive filter in SVC and suppress possible resonance between the system impedance and the passive filter. The paper introduces the scheme's main circuit structure and its working principle, mainly analyzes the control method and simulation model. Through MATLAB simulation, the results verify the effectiveness and advantage of the compensation scheme for substations in power system.
Keywords/Search Tags:Reactive power, Harmonics, Thyristor controlled reactor, Active power filter, Instantaneous reactive power theory, Simulation
PDF Full Text Request
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