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This paper proposes a two-level framework for the operation of a competitive market for reactive power ancillary services. It is argued that the first-level, i.e., reactive power procurement, be on a seasonal basis while the second-level, i.e., reactive power dispatch, be close to real-time operation. To this effect, a reactive power procurement market model is proposed here taking into consideration system security aspects. This procurement procedure is based on a two-step optimization model. First, the marginal benefits of reactive power supply from each provider with respect to system security are obtained by solving an optimal power flow (OPF) that maximizes system loadability subject to transmission security constraints imposed by voltage limits, thermal limits, and stability limits. Second, the selected set of generators is then determined by solving an OPF-based auction to maximize a societal advantage function comprising generators' offers and their corresponding marginal benefits with respect to system security, considering all transmission system constraints. The proposed procedure yields the selected set of generators and zonal price components, which would form the basis for seasonal contracts between the system operator and the selected reactive power service providers. Index Terms--Ancillary services, electricity markets, pricing, reactive power management, system operation, system security.

Current transformer (CT) saturation leads to inaccurate current measurement and, therefore, may cause malfunction of protective relays and control devices that use currents as input signals. This paper introduces an efficient compensation algorithm capable of converting from a sampled current waveform that is distorted by CT saturation to a compensated current waveform. Attractive features include quick response time, no cumulative estimation errors, desired sample-by-sample output, independent of CT parameters/characteristics and secondary burdens, and simplicity for online implementation. The accuracy and robustness of the introduced compensation algorithm are demonstrated through extensive test cases reflecting a wide range of variations in fault conditions and CT parameters. Index Terms--Control and protection, current transformer (CT), power systems, saturation effects, waveform compensation.

Multi-attribute decision making (MADM) methods have been widely used in strategic planning of electric utilities for selecting the best resource strategy with regard to the chosen attributes. In many MADM problems, however, the information available to the decision-maker (DM) is often imprecise due to inaccurate attribute measurements and inconsistent priority judgments. This paper presents an interval-based MADM approach in support of the decision making process with imprecise information. The proposed MADM methodology is based on the model of linear additive utility function but extends the problem formulation with the measure of composite utility variance. Its main contribution is to help the DM gain insight into how the imprecise data may affect the choice toward the best solution and how a set of acceptable alternatives may be identified with certain confidence. Sample case studies are provided to illustrate the concepts introduced in this paper. Index Terms--Decision support systems, electric utilities, power generation, power system planning, strategic planning.

This paper presents an overview of usage-based methods of transmission cost allocation under open access. Allocation of transmission costs involves both technical and regulatory issues, and as a result, the methods available in the literature differ in their definition and measure of the 'extent of use' of transmission resources. The primary objective of this paper is to provide a summary of recent techniques used for designing fair and equitable access fees for the recovery of fixed transmission costs. The discussion is thus organized under two major subtopics: algorithms for transmission usage evaluation and alternative pricing strategies. Numerical examples are provided to show the results using different methods. Index Terms--Cost allocation methods, open access, pricing strategies, usage of transmission resources.