Application of phase sequence exchange in emergency control of a multi-machine system

Abstract

Phase sequence exchange (PSE) is a recently developed emergency control technology. The effectiveness of PSE in a multi machine system is demonstrated in this paper. Two PSE device installation positions in a multi-machine system are first proposed. The first is at the outlet of each generator, and the second is at the connection lines between two large systems with weak connections. Based on extended equal area criterion (EEAC), a control method is then proposed. After the system out of step, the generator that need PSE and the power angle threshold can be determined quickly. When the threshold value of power angle is reached, the generator in the critical cluster exchanges phase sequence at the same time, which reduces the power angle of the one-machine to infinite bus (OMIB) image by 120° and increases the deceleration area of OMIB image. This prevents out-of-step conditions while maintaining the integrity of the system. The effectiveness of the PSE is verified using Kundur's two-area four-machine power system and the IEEE 39-bus system, and compared with other emergency control methods.