Near Optimal Closed-Loop Control. Application to Electric Power Systems

Doctoral thesis (2003)

A reinforcement learning based discrete supplementary control for power system transient stability enhancement

in Proceedings of the 12th Intelligent Systems Application to Power Systems Conference (ISAP 2003) (2003)

This paper proposes an application of a Reinforcement Learning (RL) method to the control of a dynamic brake aimed to enhance power system transient stability. The control law of the resistive brake is in ... [more ▼]

This paper proposes an application of a Reinforcement Learning (RL) method to the control of a dynamic brake aimed to enhance power system transient stability. The control law of the resistive brake is in the form of switching strategies. In particular, the paper focuses on the application of a model based RL method, known as prioritized sweeping, a method proven to be suitable in applications in which computation is considered to be cheap. The curse of dimensionality problem is resolved by the system state dimensionality reduction based on the One Machine Infinite Bus (OMIB) transformation. Results obtained by using a synthetic four-machine power system are given to illustrate the performances of the proposed methodology. [less ▲]

Closure of "a unified approach to transient stability contingency filtering, ranking, and assessment"

in IEEE Transactions on Power Systems (2002), 17(2), 528-529

A unified approach to transient stability contingency filtering, ranking and assessment

in IEEE Transactions on Power Systems (2001), 16(3), 435-443

This paper proposes a unified approach to contingency filtering, ranking and assessment in power system transient stability studies. The approach consists of two-block techniques in which the first block ... [more ▼]

This paper proposes a unified approach to contingency filtering, ranking and assessment in power system transient stability studies. The approach consists of two-block techniques in which the first block selects from a list of contingencies the a priori “interesting” ones, that the second block ranks and assesses. This Filtering, Ranking and Assessment (FILTRA) approach relies on SIME (for SIngle Machine Equivalent). SIME is a hybrid direct-time-domain stability method which combines accuracy and flexibility skills of time-domain methods with sound additional possibilities of direct methods. The FILTRA approach is fully general: it may adapt itself to the specifics of any power system (modeling, protection characteristics, etc.), any contingency scenario and mode of (in)stability (first- or multi-swing, local or inter-area mode) and any application context (planning, operation planning and real-time operation). The approach is illustrated on two EHV power systems, having different structures, control and protective devices. The adequacy of its filtering and ranking capabilities is illustrated in terms of performance criteria such as reliability (ability to consistently capture all dangerous contingencies), effectiveness (ability to avoid false alarms) and computational efficiency (ability to comply with real-time requirements). Further, the assessment task is shown to provide the operator with sound information and effective means of control. [less ▲]

An approach to modal analysis of power system angle stability

in Proceedings of IEEE Powertech 2001 (2001)

An approach to modal analysis and modal identification is proposed, capable of complementing the panoply of existing methods. It is based on a hybrid time-domain – direct transient stability method called ... [more ▼]

An approach to modal analysis and modal identification is proposed, capable of complementing the panoply of existing methods. It is based on a hybrid time-domain – direct transient stability method called SIME (for SIngle Machine Equivalent). In short, SIME uses a conventional transient stability program to transform the time varying parameters of the system into those of a one-machine infinite bus (OMIB) equivalent system. The representations of this OMIB allow substantial reduction of the original problem’s dimensionality. Many important advantages may result. For example, the multimachine system unstable equilibrium point (UEP) can readily be derived from the OMIB UEP, which is calculated analytically and unambiguously in a two-dimensional space. Further, the interplay between multimachine and OMIB characteristics and their complementary properties provides a better understanding and handling of damping, inter-area oscillations and their control. More generally, modal analysis and modal identification tasks get closer to each other and easier to handle. The paper essentially focuses on the approach as such rather than on potential applications. Simulations carried out on a 3-machine system illustrate main features. [less ▲]

Transient Stability of Power Systems: A Unified Approach to Assessment and Control

Book published by Kluwer Academic Publishers (2000)

On-line transient stability constrained ATC calculations

in Proceedings of the IEEE Power Engineering Society Summer Meeting 2000 - Volume 2 (2000)

Transient Stability Assessment, preventive control measures and dynamic A X calculations are addressed for the new deregulated EMS system. The combination of time domain analysis, SIME and Optimal Power ... [more ▼]

Transient Stability Assessment, preventive control measures and dynamic A X calculations are addressed for the new deregulated EMS system. The combination of time domain analysis, SIME and Optimal Power Flow provide a reliable solution for future transaction requirements and the current operating point. [less ▲]

Preventive countermeasures for transient stability-constrained power systems

in Proceedings of the VII Symposium of Specialists in Electric Operational and Expansion Planning (SEPOPE 2000) (2000)

A general transient stability control technique is applied to the design of preventive countermeasures consisting of rescheduling generators’ active power. The technique relies on SIME, a hybrid ... [more ▼]

A general transient stability control technique is applied to the design of preventive countermeasures consisting of rescheduling generators’ active power. The technique relies on SIME, a hybrid direct–time-domain method; and, like SIME, it preserves the accuracy of time-domain methods and their ability to handle any power system modeling, stability scenario and mode of instability. Its application to generation rescheduling may provide various patterns, able to comply with various operational specifics and strategies, as, for example, congestion management or available transfer capability calculations. The paper suggest how the technique may be shaped to choose automatically rescheduling patterns. A sample of such patterns are illustrated via simulations performed on an EPRI test system. [less ▲]

Preventive and emergency transient stability control

in Proceedings of the VII Symposium of Specialists in Electric Operational and Expansion Planning (SEPOPE 2000) (2000)

A unified approach to transient stability closed-loop control is presented. It relies on the general transient stability method called SIME, from which the Preventive and the Emergency SIMEs are derived ... [more ▼]

A unified approach to transient stability closed-loop control is presented. It relies on the general transient stability method called SIME, from which the Preventive and the Emergency SIMEs are derived. The Preventive SIME uses time-domain simulations of plausible contingencies prior to their occurrence, for the online power system monitoring from the control room. The Emergency SIME, on the other hand, uses real-time measurements, acquired on the system power plants after the actual occurrence of a contingency in order to appraise and trigger countermeasures indispensable for the system integrity. Despite fundamental differences in their design and objectives, the two approaches have also common features. This paper highlights main differences and similarities, and illustrates them on a realistic, large power system. The tradeoff between on-line preventive control and real-time emergency control is also assessed in terms of size of the involved countermeasures. [less ▲]

Transient stability-constrained optimal power flow

in Proceedings of the IEEE Power Tech'99 (1999)

This paper proposes a new approach able to maximize the interface flow limits in power systems and to find a new operating state that is secure with respect to both, dynamic (transient stability) and ... [more ▼]

This paper proposes a new approach able to maximize the interface flow limits in power systems and to find a new operating state that is secure with respect to both, dynamic (transient stability) and static security constraints. It combines the Maximum Allowable Transfer (MAT) method, recently developed for the simultaneous control of a set of contingencies, and an Optimal Power Flow (OPF) method for maximizing the interface power flow. The approach and its performances are illustrated by means of simulations carried out on a real world power system. [less ▲]