Research On Optimization Of Harmonic Elimination Based On Multi-operating Modes Of System

With a wide range of nonlinear loads connected to the power grid, the harm of the gridharmonic pollution is becoming more and more serious, and harmonic elimination has becomethe research project increasingly concerned by the power and users. Currently the most widelyused means of harmonic elimination is the use of passive filters (PF) and active power filters(APF). In this paper, the parameters of PF and APF design methods have been studied, andoptimal design methods on system multi-operating modes are proposed based on traditionalmethod.Firstly, basing on cataloguing and summarizing the harmonic major hazards, do thequantitative analysis of economic losses of various types of components caused by harmonic,and establish harmonic elimination effectiveness evaluation model.Secondly, the optimal design method of passive filter parameters based on themulti-operating modes of system is studied. The traditional design method of passive filterparameters is usually according to single operating mode of the system. When the systemoperating modes change, the harmonics and the reactive power compensation demand of thesystem will change in different degrees and the parameters designed in single operating modecan not get the optimal performance in all conditions. For the above defects of traditionalmethods, the passive filter optimal design method based on all operating modes of the systemis proposed. An appropriate mathematical model, which considers the compensatingperformance and the equipment costs of the PF in various operation modes of the system, isestablished, and the problem is solved by using the improved catastrophic genetic algorithm(ICGA). The designed parameters can obtain better compensation effects in various operationmodes at the lowest cost.Finally, the optimal design method of active power filter parameters based on themulti-operating modes of system is studied. Taking the applications of APF in high voltagesystem for example, the passive part and active part of the hybrid active power filter withsingle injection circuit (APFSIC) are optimal designed individually, and the optimizationdesign method of the active part based on all operating modes of the system is emphaticallystudied. Traditional design methods of APF main circuit parameters are individually designedfor each parameter without integrated optimal design; and the object to be compensated isusually the specific harmonic source, so the range of applications of the designed parametersis narrow. For the above-mentioned defects of the conventional method, the comprehensiveoptimization design method of the active part based on all operating modes of the system is proposed. Based on the quantitative analysis of the main circuit parameters, cost analysis andloss analysis of the main circuit, a comprehensive optimization model based on all operatingmodes is established. The designed parameters can not only meet the compensationrequirements of the system for each mode, and get the lowest cost and loss. Finally thesimulation model is established. By observing the relationship between the four-wirethree-phase output inverter system modulation area and the actual output voltage track, thecompensation performance of the designed filter is verified. And compared with the designmethod based on single operating mode, the necessity of the design based on all operatingmodes is proved.