Swing Mode Research Articles

A new design method for power modulation of dc transmission

A new design method for a PM (power modulation) controller is proposed. It is based on the eigenvalue assignment method combined with frequency response method. The proposed method is as systematic as the eigenvalue assignment method and as simple as the frequency response method. Generally speaking, the eigenvalue assignment method makes it possible to design the control system more systematically than the frequency response method. However, an observer is required to observe all state variables and a complicated matrix calculation is required. The proposed method requires no complicated matrix calculation nor the trial and error calculation. It is applicable to a large scale system and measured frequency response characteristics of the system can be used for more accurate design. In the second part of this paper, we discuss how to find the most appropriate input signal. As a result of this discussion, we show that PM is not always effective for all swing modes and the effect of PM on each swing mode varies depending upon the power flow we choose as the input signal.

Emergence of a New Swing Mode in the Western Power System

Emergence of a New Swing Mode in the Western Power System

Emergence of a New Swing Mode in the Western Power System

Low frequency synchronizing oscillations between the Pacific Northwest and Pacific Southwest have long been a characteristic of the western power system. Recently new low frequency oscillations have been observed. Simulation results and an analytical model indicate these oscillations are due to a swing mode involving the whole western loop. System measurements show the mode can become poorly damped.