电力系统稳定器相位补偿的理论研究

电力系统稳定器(PSS)广泛应用于抑制低频振荡,其传统理论基于负阻尼机理,通过补偿信号经励磁系统产生的相位滞后为系统提供正阻尼转矩。本文通过推导机端电压和励磁电流产生的磁链间传递函数,对现有的PSS相位补偿法的整定方式进行了讨论。理论上PSS应补偿的相位即为从参考电压点到励磁电流产生的磁链间传递函数的相位滞后,实际应用中,常用易于测量的机端电压与参考电压之间的相位差来代替。本文讨论了参考电压扰动和机械功率扰动对上述相位关系的影响,并作了仿真分析,指出传统的PSS相位补偿方法不能适用于任何工况,需要进一步研究其适用条件。

Research on Phase Compensation Accuracy of Power System Stabilizer

Power system stabilizer(PSS) is widely used to restrain oscillations in power system,and its traditional theory is based on negative damping theory that the positive damping torque is provided by the compensation of phase lag generated by signal passing through the excitation system.In this paper,the transfer function between the voltage of the generator and the excitation current is deduced firstly,and the tuning method of PSS phase compensation is discussed.Theoretically,the signal compensation of PSS is the phase lag of transfer function from the reference voltage to the excitation flux.In application,it is substituted by the phase lag from the reference voltage to the voltage of the generator that is easier to measure.In this paper,the influences of the reference voltage and mechanical power on phase relationship are separately discussed,and simulation and analysis are carried out.In the end,it is pointed out that the traditional phase compensation methods of PSS can’t be used to all the working conditions.