弱联工业企业电网两阶段紧急控制方法

Two-stage emergency control method for a weakly connected industrial enterprise power grid

工业企业电网负荷具有感应电动机占比高和功率因数低的特点,当同主网唯一的联络通道故障开断时,工业企业电网失稳风险突出,给紧急控制带来严峻挑战。首先,从网架、负荷和技术人员需求等方面阐述了工业企业电网的特点。并基于选用的负荷仿真模型,分析了短路故障下工业企业电网的电压频率耦合特性以及传统紧急控制措施的适应性。其次,针对故障后需要避免暂态低压高频和稳态过压低频的紧急控制需求,研究了考虑设备保护和系统保护并行动作,以及电气量响应驱动的应对策略,提出了工业企业电网两阶段紧急控制方法。最后,基于某实际工业企业电网验证了所提方法的可行性和有效性,表明通过优化控制时机可协调暂态低压快速恢复和稳态过电压的矛盾。

The load of an industrial enterprise power grid is characterized by a high proportion of induction motors and low power factor.When the only connection channel with the main network fails and disconnects,the risk of instability is prominent,posing a serious challenge to emergency control.First,the characteristics of industrial enterprise power grids are elaborated from the perspectives of grid structure,load,and technician requirements.Based on the selected load simulation model,the voltage frequency coupling characteristics of the grid in short-circuit faults and the adaptability of traditional emergency control measures are analyzed.Second,in response to the emergency control needs of avoiding transient undervoltage over frequency and steady-state overvoltage under frequency after faults,a response strategy considering parallel actions of equipment protection and system protection,as well as electrical response driven is studied.Then,a two-stage emergency control method for such grids is proposed.Finally,the feasibility and effectiveness of the proposed method are verified based on an actual industrial enterprise power grid,indicating that optimizing the control timing can deal with the contradiction between rapid recovery of transient undervoltage and steady-state overvoltage.