Online Voltage Instability Detection of ...

This paper presents a developed voltage stability index for identifying the most sensitive buses to the voltage collapse in radial distribution networks. The developed index is based on the transferred active and reactive power of a distribution line. The developed index utilizes the continuous power-flow solution calculated using real time power-flow software in distribution management systems. In this paper, the forward-backward radial load-flow is utilized to find the steady-state solution of distribution systems. Firstly, the developed stability index is tested and validated using commercial continuation load-flow program. Then, the index is used to detect the voltage instability in real-time scenarios using typical 24-hour daily load curves data for various demands with a 33-node radial feeder. The impact of distributed energy is also investigated in the studied scenarios with varied daily environmental conditions including wind speed and solar irradiation. The results show that the developed stability index provides fast assessment of the voltage stability in real time which allows operator engineer to control the demands with enough prior time of extreme loading conditions. The proposed method fits with smart grid applications since the stability index can be easily integrated with the continuous power-flow solver utilized in operating smart distribution systems