Analysis Of Power Factor And Research On Compensation Strategy For Electroslag Furnace

With the rapid development of steel industry, more and more electroslag furnaces had put into production. Because of its characteristics, it has a serious impact on power system. To improve the stability of power system, to make the quality of power better, it need to install factor compensation device. The current method is that we detect power parameters and then install compensator after equipments put into production. This subject research purpose is that we could get power factor and harmonic condition befor equipments put into production though theoretical analysis and install compensator directly. Therefore, it is imperative to analyze power factor and to research compensation strategy for electroslag furnaces.First, according to circuit theory, the thesis deduced circuit model of power supply system for key parts of effecting power factor, including nonlinear time-varying resistance arc model in smelting slag of period, the circuit model of the magnetic voltage regulator and the circuit model of power supply system of electroslag furnaces.Second, the thesis simulated and analyzed power factor and harmonic characteristic of electroslag furnaces using Matlab/Simulink. Through comparing with the actual result, the model could approximately reappeared typical power supply system characteristics of electroslag furnace. It could be used in engineering surveyor.Third, relying on model analysis, the thesis proposed the fuzzy-PID reactive power compensation control method. This method combined the PID control and fuzzy control of advantage, made the controller accuracy of the PID control and convenience and effective of fuzzy control for nonlinear systems. It had high accuracy and robustness in reactive power compensation control system with the use of nonlinear and time-varying.Finally, the thesis developed an electroslag furnaces control system of reactive power compensation based on Siemens S7-300PLC. According to the control requirements of reactive power compensator, designed software and hardware and monitoring interface of equipment. Lower computer adopts Siemens STEP-7programming software, upper computer adopts Siemens WinCC V6.2to real-time monitoring with the corresponding detection equipment and alarm system. HMI and PLC system used PPI communication way. After applied in practical electroslag furnaces project, realized the reactive power compensation and achieved better compensation effect.