抽油机工作中电动机发电运行状态分析

Analysis of motor running in generating state with pumping unit in operation.

针对普遍游梁式抽油机工作中电动机出现的发电运行状态,从扭矩、有功功率及转速的变化3方面定量分析了电动机发电运行的机理:即当抽油机系统出现“负扭矩”时,或有功功率表反转而无功功率表正转时,或电动机的转速大于磁场的同步转速时,电动机处于发电运行状态。由此导出了电动机发电运行时有关物理量如相序、转差率、转速、有功功率、电磁功率、转子输出的机械功率、电磁转矩、电压和频率的变化规律。最后分析认为抽油机工作中电动机发电运行会降低电网的功率因数并“污染” 电网。

In view of the electric motor running in generating state as a conventional pumping unit being in operation, the mechanism of motor running in generating state is analyzed from the aspects of torque, active power and speed changes The motor may run at generating state when 'negative torque' occurs in the pumping system, or the active power meter runs counter-clockwise and reactive power meter runs clockwise, or the motor speed higher than the synchronous speed in the magnetic field. Thereby the variation law of relevant physical quantities is derived. It is concluded that when the pumping unit is in operation, the motor's running in generating state will reduce the power factors of the electric network and 'pollute' the network.