Stabilization of a Large-capacity and Long-distance Transmission System by an Adjustable Speed Flywheel Generator

Abstract

SUMMARYAn adjustable-speed flywheel generator (FWG) can control both active power and reactive power rapidly. We have studied the effect of FWG installation on a largecapacity, long-distance transmission system, especially when the system includes loops. In this paper, we describe the selection of FWG location, the selection of stabilizing control input signal, and the required quantities of FWG. FWG location is selected by a PQ-sensitivity method, calculation of which is simple and permits easy understanding of the effect of both FWGs active and reactive power. As a stabilizing control input signal, we use bus voltage frequency instead of power flow because the flow changes stepwise by opening three-phase single-circuit. Additionally, we clarify the FWG quantities that must be designed, such as FWGs active power and reactive power. We considered FWGs slip to determine the quantity because the capacity of the exciter depends on slip. © 1999 Scripta Technica, Electr Eng Jpn, 127(2): 3241, 1999

Stabilization of a large‐capacity, long‐distance transmission system by a combination of a system damping resistor and an adjustable speed flywheel generator

“…A control algorithm has already been proposed for this purpose [3]; specifically, ∆ω of the generator (synchronous machine) or ∆f at the FWG location is used as the input signal.…”

“…Points F, G, K were selected for FWG installation, using the PQ sensitivity method [3,8]. The authors have shown in a previous study [3] that when system stabilization is performed by absorption of active power with an adjustable speed FWG, stabilizing control is required in order to keep the slip of the FWG rotor within a certain range, which can be implemented by using ∆ω or ∆f as the input signal.…”

“…In the case of the adjustable speed FWG, stabilization control is required in order to keep the speed of the rotor within a certain range (which is related to the active power flowing through the exciter). A control algorithm has already been proposed for this purpose [3]; specifically, ∆ω of the generator (synchronous machine) or ∆f at the FWG location is used as the input signal.…”

“…On the other hand, an adjustable speed flywheel generator (FWG) can absorb and release both active and reactive power rapidly and continuously, while providing sufficient stabilization at relatively small capacity [2,3]; in this case dynamic stability as well as transient stability is improved. However, the required capacity of the adjustable speed FWG increases with the acceleration energy of the generator for the first transient wave.…”

“…The authors have already proposed such an algorithm [3] in which the rota-tional speed of the FWG is kept within a certain range by using the parameter ∆f at the FWG location; in this study, braking control [4] is added to the previous algorithm, which improves the absorption of the active power of the first transient wave in a same-phase 1LG-OC fault. In addition, the required capacity of the adjustable speed FWG in the case of separate use is examined.…”