| This project is the major component of ShouGang Group Changzhi steel limited company science and technology program 《 110 kv Gangnan station power quality comprehensive improvement research 》. The steel corporation utilize a large number of nonlinear load converter devices, which seriously affects system power quality and threats the security and reliable operation of power system. This project analyzes and supervise the power quality of Changgang Gangnan station, and it pursues the system simulation research,aiming at two typical power quality problems and compensation governance programmes(rolling mill of steel& arc furnace) caused by load. Combing with the monitoring results and simulation analysis, this paper make a feasible management plan for promoting the power quality of Gangnan station.Firstly, this project discusses three kinds of harmonic current detection mechanism, including traditional instantaneous reactive power i_p-i_q、based on resonant regulator and Fast Fourier transform, on this basis, the instantaneous reactive power i_p-i_q harmonic current detection method based on the improved resonant controller is first time put forward in this study. Four types of simulation model of harmonic current detection method are built on MATLAB,through simulating on the actual working conditions’ symmetrical three-phase voltage, frequency, voltage distortion and load fluctuation, etc., the fourdetection methods are compared and analyzed. Meanwhile, four methods are utilized to detect the active filter respectively, the effects of different detection methods on their compensation filtering also be researched. The simulation results indicate that the fundamental harmonic distortion extracted by proposed resonant i_p-i_q method has a low rate, strongest anti-interference performance,fastest transient response. The proposed resonant i_p-i_q method effectively reduces the detection delay, improving the detection accuracy. Moreover, the active filter,which applied resonance i_p-i_q method, has a better compensation effect and tracking effect than other three methods.Secondly, this project mainly pursues the simulation analysis aiming at two traditional external characteristic of load, namely rolling mill and electric-arc furnace, utilizes proposed resonant i_p-i_q methods carrying out a harmonic detection to two systems, and focuses on compensation strategy research of two kinds of load. Furthermore, the paper researches the static var compensator(SVC) adopted by rolling mill system, comparing the Thyristor Controlled Reactor( TCR+FC) model SVC and New magnetron reactive reactor-type dynamic reactive power compensation device(MSVC). It is the first time that the TCR+FC and MSVC complete the simulation of two rolling mill system,and it utilizes two SVC devices to pursue the compensation analysis of the preparation of rolling mill system、no-load、steel rolling and rolling down four stages’ load characters respectively. The simulation results indicate : The performance of two SVC equipment is well, after compensation the system current distortion rate declines from 14.34% to 2.72%, the frequency of subharmonic dramatically decreases, fully compensating the reactive power of the system, reducing the voltage fluctuation, improving power factor, the rolling mill period increases from 0.33 to around 0.98, greatly improving the system power quality.Meanwhile, this project completes the simulation study of unbalancedthree-phase alternating current arc furnace, through adopting static synchronous compensator(STATCOM), and designing parameter and simulation modeling for each module of STATCOM, the simulation results indicate: STATCOM can effectively inhibit the harmonic, voltage fluctuation and flicker caused by arc furnace system. Three phase current phase angle difference tends to be symmetrical state, change from 300°,150°and 180°to average 120°. Besides,this paper completes the harmonic suppression of steel enterprise’s rolling mill and typical arc furnace load and the structure of reactive compensation analysis software.In a word, under the consider of actual site situation and economy requirements, according to the power quality supervision results and simulation analyze, this project makes a new governance plan for New magnetron reactive reactor-type dynamic reactive power compensation device(MSVC)of Gangnan station, and analyzes the parameter of filter device so that the enterprise can make full utilization of their original devices. Furthermore, this paper analyzes the economy and social benefits of improving the power quality of steel enterprises. |
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