EMERGENCY CONTROL DURING STABILITY CRISES BY TRACKING THE OBSERVATION DECOUPLED REFERENCE

In the last 10–12 years techniques were developed at Washington University for the control of the power system during Stability Crises in order to prevent system breakup. These techniques derive from the concept of observation decoupled reference (or local equilibrium reference). When the system state coincides with this reference it is at its stable equilibrium. While the reference has no physical identity or interpretation otherwise it can nevertheless serve to guide the system state to its stable equilibrium. This result can be acheived either by using a full set of simple control tools-one at each unit-but strictly local feedback or by using a sparse set of more sophisticated control tools along with communication between the units and the control center and central processing. The letter results, which are new and as yet unpublished, are especially appropriate for using an HV-DC system to stabilize an associated AC system. In this paper this entire area of work is summed up, its essential core exposed and some of its newest results introduced.