During the past decades, voltage instability was the reason behind several major blackouts worldwide. Continuous assessment of the system voltage stability is vital to ensure a secured operation of the system. Several voltage stability indicators have been proposed and used in an attempt to quantify proximity to voltage collapse. Some of these are computationally expensive, and others are reported not to perform as expected under all conditions. In this work a new voltage stability indicator named the P-index is proposed. This index is based on normalized voltage and power sensitivities and as such, it provides an absolute measure of the system stability. It is robust and based on solid theoretical foundations. The index has been tested on static and dynamic test platforms, and for both platforms offered a correct assessment of proximity to voltage collapse and weakest system buses. Furthermore, a method for topology change detection suitable for online systems was proposed. Dynamic stability monitoring with PMU measurements was simulated in real-time on the well-known Kundur 10-bus system and the appropriate load shedding using the P-index was calculated. Compared to the another node-based indicator, the L-index, the results show that the P-index gives a better prediction of proximity to voltage collapse and is well suited for load shedding purposes.
展开▼
