Voltage reactive security analysis in power systems with automatic secondary voltage control

The complete methodology for the steady-state voltage/reactive security analysis of power systems with automatic secondary voltage control is proposed. Both the decentralised and the co-ordinated control concepts are incorporated in a comprehensive procedure, consisting of three principal steps: contingency selection, contingency analysis and corrective control. The contingency selection stage is based on the extended load flow model and a new voltage/reactive performance index. The contingency analysis is performed next, by using either the extended load flow model (for decentralised control), or the optimum power flow model (for co-ordinated control). Finally, a simplified linear programming model for corrective resetting of pilot-bus set-point voltages is proposed with the aim to increase voltage security margins. The complete methodology was verified on the eastern part of high-voltage power system of former Yugoslavia.