DYNAMIC SECURITY DISPATCH: BASIC FORMULATION.

Abstract

Preliminary results are reported on a direct method for dynamic security dispatch in large power systems. The usual indirect approach starts with an operating point chosen to give optimal economy; then contingency testing using simulation indicates adjustments which may be needed to ensure adequate transient stability after the most likely faults. The nature of the adjustments is derived from ″intuitive feel″ for the system. Using a model given by A. R. Bergen and D. J. Hill, distribution factors are presented for systematically improving transient stability with variation of bus powers, line impedances and bus voltages. By incorporating a stability index into the cost function of economic dispatch, there can be a trade-off between the requirements for economy and stability in choosing an operating point. The method could be adapted to either planning or on-line scheduling to ensure adequate dynamic security. The application of the approach is demonstrated on a 5-bus example system. A brief discussion of the paper is appended.