一种辅助海上油田群电网大型异步电机直接起动的静止无功发生器控制方法

Control Method of Static Var Generator to Aid Direct Starting of Large Induction Motor in Offshore Oil-Rig Power System

海上油田群电网由于容量相对较小,当大型异步电动机负载直接起动时,会导致无功需求增加、电压突降、机组过载解列和负荷低压脱扣等问题。提出了一种基于静止无功发生器的改进动态无功控制策略。在常规无功/电压控制基础上,增加电机起动补偿器和切换器功能,控制电机起动过程中各调节器及其参量的切换,实现电机的平稳起动并降低对系统的冲击。控制方法应用于我国南海的涠西南油田群电网。仿真分析表明,该方法能对大型异步电机直接起动提供足够的动态无功支撑,达到稳定电压和保证燃气轮发电机和负荷安全运行的目标。

The direct starting of large induction motors such as water-injection pumps in an independent offshore oil-rig power system will result in severe problems, for instance, sharp increase of reactive power, deep drop of bus voltage, drop-off of load, or even trip of overloaded generators. To handle these problems, an improved dynamic var control method of static var generator（SVG） was presented. The method, as an improvement on the conventional var/voltage regulation, has newly developed control functions of motor-starting var compensation and switch control, by which, the motor and SVG are controlled to go through the states of pre-starting, start-preparation, motor-starting and start completion successively and smoothly. The proposed method is applied to the Southwest Wei offshore power system on the South China Sea. The simulation results show that it can provide sufficient dynamic var support for the direct starting of large induction motors and the bus voltage is maintained, the safe operation of gas-turbine generator and load is guaranteed.