Research On The Control Method Of Statcom In Smart Grid

With the increase of nonlinear load and impact load in power grid, power qualityproblems become the focus of people’s attention,and reactive power compensation andharmonic suppression technology also become research hotspot. As one of of the flexible actransmission device, the static synchronous compensator (STATCOM) conform therequirement of building strong smart grid and the reactive power compensation technology,it express important social significance to improve the quality of the residents making useof electricity and reduce emissions. Through the theoretical analysis and modelingsimulation, the topic studys systematically STATCOM reactive power detection technology,control technology and the design methods of multi-objective fuzzy controller.First of all, it analyzes the working principle of STATCOM, establishs dynamicmathematical model and steady-state mathematical model of STATCOM. Throughanalyzing of the indirect current control and direct current control, select instantaneouscurrent control method based on abc shaft as control method.Then, it makes principle description and simulation analysis to the traditional reactivecurrent detection technology of p-q test and ip-iq test.Aiming at the limitations anddeficiency of the traditional detection technology,presents an improve detecting technologybased on instantaneous reactive power theory.This method not only removed phase-lockedloop, simplify the circuit structure,but also get rid of the low-pass filter type, order numberand the cut-off frequency influence on response time, improve the detection accuracy andresponse speed.Voltage without distortion and with distortion were simulated respectivelyof improved detection,the result of simulation shows that this method not only canaccurately detect the reactive power and harmonic current, and has high precision, fastresponse characteristics.Direct current control on the basis of combining the hysteresis control and improvedof reactive power detecting methods are used to establish the simulation model ofSTATCOM,and the perceptual load and capacitive load are simulated respectively.Theresults show that the design of STATCOM has good compensation effect.Finally,from the perspective of maintaining steady node voltage and mitigatingvoltage flicker, improving transient stability limit of the system,damping power system oscillations, control laws of each target were designed respectively, then a multi-objectivefuzzy controller of STATCOM was designed through using fuzzy controller to adjust thecontradiction between the control target.Next a dual-machine power system simulationdiagram was build with Matlab/Simulink, the advantages of multi-target controller wedesigned were verified ultimately by comparing with the simulation results of the inversesystem-PI controller.