As electrical power high voltage transmission systems become more heavily loaded due to increased electric loads and larger transfers of power between utilities, efficient system operation is becoming threatened due to static security, transient stability, and more recently voltage stability constraints. The objective of the research proposed here is to use energy function methods to develop a unified measure of power system security. To date energy functions techniques have been applied successfully to the transient stability and maximum stable loadability problems; however, little work has been done to access dynamic voltage stability. Such a measure of system voltage security is essential for economic and reliable operations. Research is to be performed in four areas. The first area will be an investigation of the modeling detail required to adequately capture the dynamics associated with voltage instability. More detailed models are anticipated for generators, loads, transformers and static var compensators (SVCs). Second, research will be done on the development of integrated energy function security framework, which will require a modified energy function, along with a new paradigm to incorporate the varying time scales of the voltage dynamics (from seconds to tens of minutes). Third, the relationship of the voltage stability unstable equilibrium points (UEPs) with the transient stability UEPs will be investigated; also work on the efficient calculation of the UEPs will also be done. Lastly, integration of energy methods into existing control center applications will be explored.
