Influence of Generator Capability Curves Representation on System Voltage and Reactive Power Control Studies

The influence of generator capability chart representation (overexcited zone) on system voltage and reactive power control studies is examined. A load pick-up in a power system is simulated by means of a computer program and the steady--state operation in some "critical" conditions (heavy power flows and low power factors) is analyzed. Under these conditions the adoption of the simplified representation (rectangular) or of a more exact representation of the actual capability charts, may influence the search for feasible solutions to a considerable extent. Possible criteria for the optimization of system voltage and reactive power scheduling in critical conditions are also discussed on the basis of this more L exact representation.