Voltage stability of power systems and energy functions

Abstract:- Energy function analysis offers a different geometric view of voltage collapse. In this approach, a power system operating stably is like a ball which lies at the bottom of a valley. The stability can be understood as the ball rolling back to the bottom of the valley when there is a disturbance. As the power system changes, the landscape of mountains and mountain passes surrounding the valley changes. A voltage collapse corresponds to a mountain pass being lowered so much that with a small perturbation the ball can roll from the bottom of the valley over the mountain pass and down the other side of the pass. The height of the lowest mountain pass can be computed and used as an index to monitor the proximity to voltage collapse. Key-words:- Voltage collapse, energy function theory, system stability. WSES MCP'99 Proceeding