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Publications

Publications by CPES

1996

A fuzzy approach to power system planning and power transactions in a competitive environment

Authors
Saraiva, JT;

Publication
PROCEEDINGS OF THE 35TH IEEE CONFERENCE ON DECISION AND CONTROL, VOLS 1-4

Abstract
The deregulation of the electricity industry places a number of complex questions related namely with planning and operating activities. In this paper one will enumerate some of these issues and give an overview about the way this process is being handled in several countries. In the paper one will also describe a methodology to identify the most adequate components to be reinforced considering that one aims at reducing the risk felt by the planner if loads are modeled by fuzzy numbers. At the end, fuzzy concepts are integrated in a model to validate from a technical point of view a set of trades established between electricity buyers and sellers in a competitive environment.

1996

Enhanced fuzzy power flow models integrating correlation between nodal injections

Authors
Saraiva, JT; Duarte, F;

Publication
MELECON '96 - 8TH MEDITERRANEAN ELECTROTECHNICAL CONFERENCE, PROCEEDINGS, VOLS I-III: INDUSTRIAL APPLICATIONS IN POWER SYSTEMS, COMPUTER SCIENCE AND TELECOMMUNICATIONS

Abstract
In this paper one reviews some concepts related to fuzzy load modeling namely dealing with correlated and uncorrelated models. After briefly describing DC and AC fuzzy power flow models, one addresses the problem of integrating information about correlations between node consumptions or injections in these models. This information will lead to a correction phase performed after running the previous models. This correction phase is organized as a linear programming problem solved in a very efficient way as one takes advantage of the special structure of the problem. The methodology will be illustrated using a case study based on the IEEE 24 bus/38 branch Test System.

1996

Dynamic state estimation algorithm and bad data processing

Authors
Ferreira Isabel, M; Barbosa, FPM;

Publication
Proceedings of the Universities Power Engineering Conference

Abstract
This paper presents an efficient information debugging methodology, using a dynamic state estimation algorithm which, through the use of a dynamic model for the time evolution of the system state, will meet simultaneously two objectives: the filtering of the incoming data and the forecasting of the state vector one step ahead. Based on this last characteristic a scheme for the detection of suspicious information is built.

1996

A dynamic state estimation algorithm with information debugging

Authors
Ferreira, IM; Barbosa, FPM;

Publication
MELECON '96 - 8TH MEDITERRANEAN ELECTROTECHNICAL CONFERENCE, PROCEEDINGS, VOLS I-III: INDUSTRIAL APPLICATIONS IN POWER SYSTEMS, COMPUTER SCIENCE AND TELECOMMUNICATIONS

Abstract
This paper presents an efficient information debugging methodology, using a dynamic state estimation algorithm which, through the use of a dynamic model for the time evolution of the system state, will meets simultaneously two objectives: the filtering of the incoming data and the forecasting of the state vector one step ahead. Based on this last characteristic a scheme for the detection of suspicious information is built.

1996

Phasor visualizer for investigation, teaching and control of induction motor

Authors
Araujo, RE; Goncalves, JJ; Tavares, A; Freitas, DS;

Publication
MELECON '96 - 8TH MEDITERRANEAN ELECTROTECHNICAL CONFERENCE, PROCEEDINGS, VOLS I-III: INDUSTRIAL APPLICATIONS IN POWER SYSTEMS, COMPUTER SCIENCE AND TELECOMMUNICATIONS

Abstract
The phasor visualizer presented in this paper is performs real time calculation in steady-state and transient conditions of simultaneous electromagnetic torque, magnetic flux, voltages and currents of an induction motor supplied with sinusoidal voltages or through frequency converters and provide an oscillographic display. The phasor visualizer is an instrument for analysis, investigations and teaching of AC machine drives. The instruments needs no shaft position or speed sensor, it uses exclusively the acquired stator currents and voltages. The main fields of application are: element of a monitoring system, integration in a control unit, research tool for induction motor drives, and test shop. Practical results of the implementation are be presented and discussed.

1996

Conditions for equivalence between the compositional rule of inference and the compatibility modification inference

Authors
Villar, J;

Publication
IEEE International Conference on Fuzzy Systems

Abstract
This paper shows that the compositional rule of inference reduces to the compatibility modification inference, when the antecedent of a fuzzy rule and its input fulfil some properties. Two main types of implications are investigated, those generalizing the classical material conditional (residuated and strong implications), called in this paper m-implications, and those generalizing the classical Cartesian product (t-norms and pseudo-conjunctions), called t-implications. For m-implications, when their maximum modus ponens generating function is used, the compatibility measure depends obviously on the relationship between input and antecedent, but also on the t-norm the implication comes from. Similarly, for t-implications, also used as their own modus ponens generating function, the compatibility measure depends again on the input and antecedent, but also on the t-norm they come from. As it could be expected, in the first case the compatibility measure is a degree of the inclusion of the input into the antecedent, while in the second one it is a degree of the intersection of both.

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