Research On Electric Energy Quality Algorithm Of Electric Arc Furnace Based On New National Standard

The quality of power quality affects the safety and operation of power systems.The management of power quality is an important part of power system operation.Countries around the world have paid close attention to the detection and analysis of power quality,and have formulated corresponding power quality standards.In the 1990 s,the State Bureau of Technical Supervision issued a unified power quality standard,but the standards were ambiguous in actual implementation.According to the problems of the old national standard and modern power quality,in 2008,the State Bureau of Technical Supervision revised the national standard for voltage imbalance,voltage deviation,voltage fluctuation and flicker.According to the revision of the new national standard,how to update the power quality algorithm and develop power quality testing equipment to meet the requirements of the new national standard and engineering applications has become a research hotspot in the power industry.Based on the new national standard for power quality,combined with the "electric arc furnace active comprehensive compensation" project,this paper designed a power quality algorithm that meets the requirements of the new national standard.Based on this,a prototype of power quality testing equipment meeting the requirements of the new national standard was developed.The main work carried out in the thesis is as follows:Comparative analysis of new and old power quality national standards.The definition of power quality indicators such as voltage and current RMS,harmonics,three-phase unbalance,voltage deviation,voltage fluctuation and flicker is studied in the new national standard.The new and old national standards are compared in the measurement methods,numerical calculations and numerical values of the above indicators.The limited changes,in particular,summarize the 18 revisions of harmonics,three-phase unbalance,and voltage deviation in the new national standard.According to the revision of the new national standard,specific requirements are put forward for the algorithm design and prototype development of this paper.Power quality algorithm design and simulation.According to the new national standard and the requirements of the electric arc furnace project,the Fast Fourier Transformation(FFT)is applied to the harmonics,and the principle of the base 2-DIF FFT is studied.Based on this,the algorithm is designed.The balance is calculated by the symmetrical component method and compared with the signal delay method.The algorithm of half-cycle discretization is used for voltage deviation,voltage fluctuation and flicker.Based on the Matlab platform,the m language code of power quality algorithm is programmed.The UIdisplay interface is designed.The simulation model of the electric arc furnace project is built.The simulation results and the theoretical values calculated by the national standard are compared to verify the correctness of the algorithm.Experimental verification.The experimental test was completed at the EAF project site and compared with the data of the synchronous power quality analyzer.The experimental results show that the prototype device can meet the requirements of the project for data sampling and storage,data calculation and communication.The power quality algorithm meets the expected design,and the prototype device meets the national standard requirements and engineering applications.