Abstract: Voltage instability protection for an electric power system is implemented by determining a change in power injected into a region of interest within the electric power system based on synchronized power measurements from different power injection points of the region of interest, and by determining a change in power absorbed by one or more loads in the region of interest based on synchronized power measurements from different load points of the region of interest. A change in power loss for the region of interest is determined based on the difference between the change in power injected into the region of interest and the change in power absorbed by the region of interest. A voltage instability condition is indicated when the change in power loss for the region of interest approximates the change in power injected into the region of interest.

Abstract: A system for producing electrical power based on wind energy is capable of predicting its power output. The system includes a set of wind turbine units, a first plurality of sensors each adapted to sense at least one wind characteristic at some of the wind turbine units, and a second plurality of sensors remotely located. At least one wind characteristic is estimated at the wind turbines not having one of the first plurality of sensors based on sensing by the first plurality of sensors and an estimate of changes in wind characteristic at wind turbine units caused by presence of other wind turbine units. The magnitude of electrical power production by the set of wind turbine units at at least one predefined point in time in the future is predicted based on the estimated wind characteristics and sensed wind characteristics.

Abstract: Voltage instability protection for an electric power system is implemented by determining a change in power injected into a region of interest within the electric power system based on synchronized power measurements from different power injection points of the region of interest, and by determining a change in power absorbed by one or more loads in the region of interest based on synchronized power measurements from different load points of the region of interest. A change in power loss for the region of interest is determined based on the difference between the change in power injected into the region of interest and the change in power absorbed by the region of interest. A voltage instability condition is indicated when the change in power loss for the region of interest approximates the change in power injected into the region of interest.