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Within an optimal power flow market clearing framework, this paper provides expressions to compute the sensitivities of locational marginal prices with respect to power demands. Sensitivities with respect to other parameters can also be obtained. An example and a case study are used to illustrate the expressions derived. [ABSTRACT FROM AUTHOR]

This paper presents a systematic way of using linear analysis techniques to find and rank candidate locations for controlled shunt and series compensations for power system damping purposes. A two-stage approach based on frequency response computations is introduced using a 4780-bus system model of the Nordic power system for assessment of controlled shunt compensations. In the first stage, their controllability is determined by means of long-distance frequency responses. In the second stage, the frequency responses of the transfer functions from the bus shunt susceptance to the bus voltage magnitude are computed for buses that have shown high controllability. This paper shows that the interpretation of the frequency responses of these local transfer functions, for buses that have exhibited high controllability, is in most cases sufficient to predict the behavior of controlled shunt compensation at different locations in the system. The interpretation is based on the observation of amplitudes, phase angles, and the rate of change of the phase angles around the interarea resonance frequencies. An important finding was that controlled shunt compensation located in an area with high-power import over ac interconnections lowered the damping of at least one of the interarea oscillation modes if operating in normal voltage control. This finding was also verified with nonlinear simulations. The first stage of the proposed frequency response-based approach has also been introduced for assessment of controlled series compensations. The strength of the new methods is that they can be used with both linear and nonlinear system models. [ABSTRACT FROM AUTHOR]

This paper describes an innovative scheme based on a pluralistic load frequency control (LFC) and aimed at performing cross-border power control, secondary frequency regulation, and internal congestion resolution. Such an LFC scheme applies to a pluralistic block of control areas, whose regulators can adjust the production of their generators with respect to the request of the coordinating area when the power flows through grid sections exceed their maximum admissible values. This paper introduces the theoretical aspects and functional design of such an advanced LFC scheme, capable of controlling at the same time the cross border exchanges of the pluralistic block and the power flows between network subareas defined as market zones. Simulations on the Italian power system show the performance, main advantages, and limits of the proposed control method. [ABSTRACT FROM AUTHOR]

Performance specifications place restrictions on the dynamic response of many systems, including power systems. Quantitative assessment of performance requires knowledge of the bounding conditions under which specifications are only just satisfied. In many cases, this limiting behavior can be related to grazing phenomena, where the system trajectory makes tangential contact with a performance constraint. Other limiting behavior can be related to time-driven event triggering. In all cases, pivotal limiting conditions can be formulated as boundary value problems. Numerical shooting methods provide efficient solution of such problems. Dynamic performance. assessment is illustrated in the paper using examples drawn from protection operation, transient voltage overshoot, and induction motor stalling. [ABSTRACT FROM AUTHOR]

We show that the system loss function in a power network is bounded below by any number of supporting hyper-planes in the space of generalized injections. A supporting hyper-plane is defined by the linear Taylor series expansion of the system loss function around a given operating point. The supporting hyperplane property is valid provided that the expansion point is sufficiently near the flat-voltage profile. We have assessed experimentally the range of validity of this assumption, called the range of hyper-plane support (RHS), showing that for typical networks, the RHS is broad, particularly when the bus voltages are controlled near 1 per unit. The supporting hyper-plane model was also tested as part of an economic dispatch with transmission losses to demonstrate that this linear model provides the same results as when the losses are treated as a nonlinear function. [ABSTRACT FROM AUTHOR]