In this paper, we develop a new damping control scheme for FACTS devices, using bang-bang modulation of FACTS signals. The scheme is used to attenuate quickly the system's most dominant mode which is identified using online Prony analysis. An analysis framework to evaluate the robustness of the control schemes to changes in operating conditions and to time-delay is also proposed. Simulation results on various test systems show that following large disturbances, the proposed control scheme is very effective to mitigate the power system critical modes of oscillation. Furthermore, the problem of control interactions is completely avoided with the proposed control scheme.

A Power Oscillation Damping Control Scheme Based on Bang-Bang Modulation of FACTS Signals

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Design of wide-area damping control systems for power system low-frequency inter-area oscillations

This report is one of six reports developed under the U.S. Department of Energy (DOE) program in Power System Integration and Reliability (PSIR). The objective of this report is to review, analyze, and evaluate critical reliability issues demonstrated by recent disturbance events in the North America power system. Eleven major disturbances are examined, most occurring in this decade. The strategic challenge is that the pattern of technical need has persisted for a long period of time. For more than a decade, anticipation of market deregulation has been a major disincentive to new investments in system capacity. It has also inspired reduced maintenance of existing assets. A massive infusion of better technology is emerging as the final option to continue reliable electrical services. If an investment in better technology will not be made in a timely manner, then North America should plan its adjustments to a very different level of electrical service. It is apparent that technical operations staff among the utilities can be very effective at marshaling their forces in the immediate aftermath of a system emergency, and that serious disturbances often lead to improved mechanisms for coordinated operation. It is not at all apparent that such efforts can be more » sustained through voluntary reliability organizations in which utility personnel external to those organizations do most of the technical work. The eastern interconnection shows several situations in which much of the technical support has migrated from the utilities to the Independent System Operator (ISO), and the ISO staffs or shares staff with the regional reliability council. This process may be a natural and very positive consequence of utility restructuring. If so, the process should be expedited in regions where it is less advanced. « less

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Consortium for Electric Reliability Technology Solutions Grid of the Future White Paper on Review of Recent Reliability Issues and Systems Events

Bifurcation-theoretic issues in the control of voltage collapse

Several studies have shown that the way to design controllers for the HVDC links impacts the transient behavior of the electric system in which the latter are inserted. This can be exploited to improve the performances of the stability of the power system. In this paper, a robust multivariable control design for the converters of an HVDC link is proposed. It is based on the coordination of the control actions of the HVDC converters and the use of a control model. The latter takes into consideration, in addition to the dynamics that mostly impact stability of the neighbor zone of the HVDC link, several cases of faulted situations modeled as uncertainties. An H∞ controller allowed us to achieve robustness against such uncertainties. The new controller is tested in comparison with the standard vector control and an optimal LQ controller using the Eurostag simulation software on both academic and realistic large-scale power systems.

https://hal.archives-ouvertes.fr/hal-01450076/document

Robust grid-oriented control of high voltage DC links embedded in an AC transmission system

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. >

J.F. Hauer

Papers

Robustness issues in stability control of large electric power systems