Based On Symmetrical Component Method Of Submerged Arc Furnace Short Net Compensation Technology

Submerged arc furnace has the characteristics of low-voltage, high current and the load of non-linear in the course of its operation. Due to rapidly changing arc length, a substantial increase in reactive power grid, energy consumption large, and will produce voltage fluctuations, flicker, three phase imbalance, the negative sequence current problems, leading to grid instability. There is no doubt, reactive power compensation is inevitable.In this paper, the contents comes from the project submerged arc furnace reactive power compensation systems supported from the national scientific and technological, and selected a factory 103 furnace reactive power compensation device for study.Based on symmetrical component method to calculate the negative sequence current, and then calculate the compensation susceptance value, and then carry out TCR+TSC reactive power compensation. As the symmetrical component method is only suitable for linear systems, the first collection to the current Fourier transform, transform the results extracted from the fundamental component for the sub-value symmetrical component method using decomposition of negative sequence component, the calculation of compensation power sodium values, and then use PWM wave control the firing angle in size, to realize the negative sequence current compensation, the above data acquisition and trigger angle control by the MCU to complete the remaining part of the calculation carried out in the IPC.Hardware components used mainly for industrial using highly reliable control of Motorola microcontrollers, first, sending the voltage and current values collected by sampling circuit to the MCU, A/D converters, then convert the results into the industrial control machine, firing angle of thyristor calculated by industrial machine is given back to SCM, according to the return value sent PWM wave by the microcontroller, controlled by the trigger circuit compensation capacitor capacitance and inductance of the inductive reactance, in order to achieve dynamic adjustment of compensation for the admittance. Software components, including part and control part of the algorithm, due to the calculated capacitance value and the compensation susceptance values, need to adopt a linear equation approximation method to determine the compensation control firing angle, this paper, cubic spline interpolation to solve the thyristors firing angle.The use of MATLAB software, conducted the computer simulation of thyristor trigger angle fitting cubic spline interpolation function, the negative sequence current compensation and overall compensation circuitry. Simulation results show the use of spline function calculated firing angle can effectively improve the calculation accuracy, the negative sequence current compensation simulation results show that high-order harmonics are effectively suppressed current distortion significantly reduced. Overall compensation circuit simulation results show high accuracy compensation of the method used in this compensation used wit. The content of the text has a certain referential significance in the next step in the completion of the actual system design and application.