Analysis And Calculation On Load-Current Of12.5MVA Submerged Arc Furnace

Ferroalloy is mainly produced by submerged arc furnace (SAF). With the problems of resource shortage, energy crisis and environmental pollution, it demands higher requirement for energy saving and emission reduction of SAF. To build the electrical model of SAF and to study the detection problem of key parameters is of great significance to realize the optimal control of SAF, to improve the production efficiency, and to reduce the energy consumption.The SAF is a typical load which posses the characteristics of nonlinear, strong coupling and time variation. According to the composition characteristics of power supply system, this paper emphatically analyzes the structural of short net, calculates the parameters of equivalent circuit and proposes a optimal method to design the short net. Taking the method which is hybrid the mechanism modeling and system identification, with the equation of energy balance, to build the relation model of electrode voltage and current. And then using the PSO algorithm to identify the parameters of this model. With the help of power supply system model, it can create the theoretical basis to analyze the SAF’s electrical characteristics, to make the optimal control strategy and to solve the power quality problems.The electrode current of SAF has been the main factor to decide the three-phase power of SAF. Its value reaches10thousand or100thousand ampere. Considering the difficulty in testing the load current of SAF, a soft sensing method based on superposition theorem of power supply for load current is proposed. With a novel filtering algorithm based on modified wavelet threshold, to preprocess the voltage of short net and to obtain the valid data. After obtaining the effective signal by filtering, take Fast Fourier Transform (FFT) as decomposition algorithm to get each excitation waveforms, then stacking excitations using superposition theorem, which can indirectly test the phase current and electrode current online. The simulation and experimental results both show the feasibility and effectiveness of the proposed method. Testing the load current successfully creates the condition for optimal control of three phase balance in steel smelting process.At last, this paper designed the hardware and software environment of SAF optimal control system. With the application of theories and methods in this paper, the problems of SAF power supply model and the load current detection are solved. The result shows that the theories and methods in this paper can obtain a good application effect.