Submerged Arc Furnace Mixed Type Dynamic Reactive Power Compensation Research Of Key Technologies

Submerged arc furnace has a huge reactive power consumption in the process of production, and a series of power quality problems which include harmonic pollution, voltage fluctuation and drop, three-phase power imbalance are caused easily because of the irregularity of arc discharge. Thus, reactive power compensation and power quality management are necessary for submerged arc furnace. Submerged arc furnace is an indispensable equipment for smelting ferroalloy, upgrading and rebuilding the equipment will produce great economic benefit for iron and steel enterprises, which has important economic significance.This paper firstly analyses the basic structures and electrical characteristics of submerged arc furnace, and then studies the basic electrical parameters of submerged arc furnace transformer, short-net and furnace, meanwhile the mathematical model of submerged arc furnace power supply system is established. The main kinds of hybrid reactive power compensation device at present are introduced, and designs the main circuit topology structure of a hybrid dynamic reactive power compensation device(FC-TSC-STATCOM) according to the basic situation of submerged arc furnace. The working principle and operating characteristics of FC, TSC and STATCOM are detailedly introduced. Taking cycle cutting control to FC will make the cutting equality of each FC power capacitor In theory. Taking thyristor zero switching on-off control to TSC and adding a differential part in detecting link could make the switching more safe and reliable, prevent the switching oscillation problem in the cutting process, prolong the life of the TSC, and reduce the three-phase unbalance factor of submerged arc furnace short-net through separately controlling to each phase of TSC. Direct current control strategy is adopted for STATCOM and with the instantaneous reactive power theory to ensure the quickness of tracking the reactive power changes of submerged arc furnace and suppress the voltage fluctuation and flicker in time. For hybrid control, a coordinated control method is putted forward based on the judge system rules. The whole system was set in the Matlab/Simulink software to verify the effectiveness of the proposed control method and the experimental results prove the reliability and effectiveness. Finally capacity allocation is conducted to the compensation device of hybrid dynamic reactive power compensation device(FC-TSC-STATCOM) and at the same time to carry on hardware and software design to the device.