基于PLC的变电系统经济运行控制系统研究

Research on Economic Operation Control System of Power Distribution System Based on PLC

变压器的最高效率并不出现在满载时,只有在最佳负载率时,变压器的效率最高。文中提出的变电控制模型,控制系统根据终端负荷变化,实时控制变压器投入容量,使其尽可能运行在最佳负荷率,最大限度地降低变压器的电能损耗。文中以三台变压器并列运行为例,运用临界负载法计算变压器应投入量。电压电流采集系统通过A/D模块将终端负荷数据传输至CPU,变压器投入量经PLC数字量输入,CPU运算处理后,由PLC数字量输出控制接触器,改变变压器投切量。智能设备站与远程设备站通过CC-Link模块与PLC主站进行通信,人机界面用于变电系统运行控制模式设置及切换,监控负荷的大小,负荷变化曲线以及故障报警,达到操作智能化等功能。变配电智能化可以提高变配电系统的稳定性与可靠性,控制系统在中低压配电网中有广泛的推广价值。节能降耗效果分析说明,系统可以实现电能节约。

The highest efficiency of the transformer is not in full load,but in optimal load rate.In this article,the control system can real-time control transformer input capacity according to the terminal load changes.The transformer runs in the optimal load rate so that minimizes the transformer power loss.The model is based on three transformers in parallel operation.Transformer inputs should be calculated using the critical load method.Control system is the Mitsubishi Q series PLC.Voltage and current acquisition system transfers the terminal load data to the CPU through the A /D module.Transformer inputs feedback by the PLC digital input.PLC digital output adjusts transformer input capacity.Intelligent device station and remote device station communicate with the PLC master station though CC-Link module.The man-machine interface can set and switch control mode of power system operation,monitor the load,Display the load curve and failure alarm,to achieve the intelligent operation.Intelligent power distribution can improve the power distribution system stability and reliability.Control system has wide promotion value in low voltage distribution network.Data analysis shows that the system can achieve energy savings.