多机系统多变量励磁控制下的阻尼守恒、阻尼竞争与阻尼协调

本文从多机电力系统总阻尼的概念出发,证明了多变量励磁控制并不增加电力系统总阻尼.在AVR的基础上附加转速、功角、功率,乃至于附加远方机组任意信号的复杂多变量励磁控制方式下,电力系统总阻尼保持守恒,其数值与单纯AVR控制时相等.由于电力系统所有模式阻尼之和为常数,所以在试图增加某一模式阻尼时必然导致削弱其他模式的阻尼.这是设计多变量励磁规律时的阻尼竞争现象.附加励磁控制的实质仅仅是在各模式阻尼相互竞争、彼此消长中寻求协调与平衡.当系统满足阻尼守恒条件时,给所有模式增加阻尼的企图是不可实现的.

Damping competition and damping coordination of additional excitation control in multi-machine power systems

Based on the conception of general damping of multi-machine power systems,it is proved that additional excitation control does not increase general damping of power systems.When AVR is added to other signals,such as speed,angle,active power,et al.,power systems have equal general damping.Because total amount of all the modes' damping is a constant that does not change on any conditions of additional excitation,damping competition will happen in the course of designing additional excitation rule.The essence of additional excitation control is only a coordinate strategy,and maintaining damping equilibrium among all the modes' is the real subject.The phenomenon of damping competition indicates that when a mode's damping is added,another mode's damping will be reduced. So an excitation rule designer's work is seeking for a compromise idea which makes all of the modes' damping reasonable.And a designer must realize that the attempt to increase every mode's damping is not always available.