Application of FACTS Devices for Power System Transient Stability Enhancement

Abstract

The massive growth of interconnected power systems due to increasing demand for electrical energy has given rise to numerous challenges. These include power swings and oscillations due to outages, blackouts, natural disturbances and system faults that occur along transmission lines, load and generation points. Blackouts have been witnessed in the recent years in countries around the world. These major disturbances cause power system instability and pose difficulties to system operation, planning and maintenances scheduling. In these circumstances, Flexible Alternating Current Transmission System (FACTS) controllers such as the Interline Power Flow Controller (IPFC) Static Synchronous Series Compensator (SSSC) and Unified Power Flow Controller (UPFC) can considerably improve transient stability thus enhance overall system stability during disturbances. Alongside the property of fast control of active and reactive power in power system, SSSC, IPFC and UPFC devices also play an additional role in transient stability enhancement and therefore play vital in system stability control. This research has delved into the specific and comparative performances of three devices as far as damping of system oscillations is concerned. It has gone further to look at voltage support and loss reduction features attributed to each device vis-à-vis damping of oscillations to enable power system planners merge the transient stability, loss reduction and voltage support characteristics of the three/ devices. In this research, use of UPFC, SSSC and IPFC FACTS controllers were applied in Transient Stability Enhancement (TSE) analysis considering dynamic environment of the standard IEEE 14 bus test system. TSE for single compensation device (SSSC) and double compensation devices (UPFC and IPFC) were accomplished successfully. The inherent properties of the three devices were deduced for TSE. The research is inspired by the need of automating power system transient stability control by outlining the distinguishing features of three FACTS devices for TSE using with focus on their compensation properties. By incorporating fast acting and appropriately located FACTS devices, the xv corresponding time domain responses were obtained and analysed with and without the devices. This research has effectively brought out the specific and comparative performances of three devices as far as damping of system oscillations is concerned. The results have shown significant enhancement of the transient stability when the FACTS devices are applied by considerably reducing post-fault settling time of power system as well as effectively damping network oscillations in contrast with when the devises are not applied. Synchronous machine parameters’ responses for the three FACTS devices, appropriately placed, were obtained and analysed successfully.