Robustness issues in stability control of large electric power systems

Controller based alternatives to direct power system reinforcements can be very attractive, but they raise some difficult issues. The uncertainties that attend large scale power system applications preclude complete demonstrations of controller robustness. Functional reliability must be assessed more broadly, in ways that incorporate engineering judgment and are fortified through sound practice. Uncertainty which cannot be mitigated should be accommodated in controller design, and in controller operation. Necessary countermeasures include examination of power system dynamics, expanded development and use of mathematical tools, and more aggressive use of information technology at all stages of the engineering process. These should be supplemented by an in depth dialog, between the control engineering and power communities, as to what actually constitutes acceptable risk and sound practice