电解铝整流系统建模与稳流协调控制策略

Modeling and Current Stabilization Coordinated Control Strategy of Rectifier System in an Aluminum Smelter

介绍了大功率直流电解铝供电系统结构,建立了包括电解槽负载模型、饱和电抗器(SR)模型以及有载调压变压器(OLTC)的整流系统模型,提出了稳流协调控制策略:OLTC可对系列电流进行离散性的粗调,SR可在一定范围内实现对系列电流的连续性微调,两者结合能有效地解决机组投入与退出、阳极效应发生等大扰动下的稳流精确控制问题。基于电磁暂态分析软件包(EMTDC)搭建了6机组整流系统,对网侧电压波动、负荷波动等工况进行了仿真分析,仿真结果表明:所提协调控制策略能保持直流系统处于最佳的运行状态,可实现电解铝生产过程中电流的平稳。

The structure of high-power DC supply system of the aluminum smeher is described and the models of electrolytic cell, saturable reactor （SR） and on load tap changer （OLTC） are built respectively. A coordinated control strategy based on SR and OLTC is prnposcd to keep the DC current stable, in which the OLTC is used for discrete coarse control of series current and the saturable reactor is used for continuous fine control. The proposed coordinated control strategy, has good performance when a large disturbance occurs, such as single unit is out of operation, or the anode effect occurs, et al. The rectifying system of 6 units is built by PSCAD/EMTDC, and simulation is carried out on grid voltage and load fluctuations. The simulation results show that the control strategy can keep the DC system on the optimum operation status and the series current stable.