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Publications

Publications by Victor Silva Freitas

2017

Robust State Estimation Based on Orthogonal Methods and Maximum Correntropy Criterion

Authors
Freitas, V; Coasta, AS; Miranda, V;

Publication
2017 IEEE MANCHESTER POWERTECH

Abstract
This paper presents an orthogonal implementation for power system state estimators based on the Maximum Correntropy Criterion (MCC). The proposed approach leads to a numerically robust estimator which exhibits self -healing properties, in the sense that gross errors in analog measurements are automatically rejected. As a consequence, robust estimates are produced without the need of running the state estimator again after bad data identification and removal. Numerical robustness is achieved by means of a specialized orthogonal algorithm based on fast Givens Rotations, which is able to handle the dynamic measurement weighting mechanism implied by the Parzen window concept associated to MCC. Results for a 3 -bus test system are presented to properly illustrate the Correntropy principles, and several case studies conducted on the IEEE 30 -bus and 57 -bus benchmark systems are used to validate the proposed methodology.

2015

Integrated State & topology estimation based on a priori topology information

Authors
Freitas, V; Costa, AS;

Publication
2015 IEEE Eindhoven PowerTech, PowerTech 2015

Abstract
This paper addresses the simultaneous estimation of state variables and network topology in the context of power system real-time modeling. The proposed method assumes that selected substations are modeled at the bus section level, and circuit breakers and disconnects are explicitly represented. Available information on the statuses of such switching branches are then treated as a priori topology information to be processed by a specialized estimator. The presumed topology will eventually be either validated or corrected by using the information conveyed by real-time measurements. An algorithm based on a fast version of orthogonal Givens rotations is employed to solve the integrated state & topology estimation problem. The proposed method preserves the bad data processing capabilities of weighted least-squares state estimators. The performance of the integrated state & topology estimator is assessed through its application to test systems derived from IEEE benchmark networks. © 2015 IEEE.

2015

Estimação Integrada de Estados e Topologia Baseada em Informação A Priori sobre Status de Dispositivos Chaveáveis

Authors
Victor Freitas,; Antonio Simões Costa,;

Publication
Anais do VI Simpósio Brasileiro de Sistemas Elétricos

Abstract

2017

Merging conventional and phasor measurements in state estimation: a multi-criteria perspective

Authors
Tavares, B; Freitas, V; Miranda, V; Costa, AS;

Publication
2017 19TH INTERNATIONAL CONFERENCE ON INTELLIGENT SYSTEM APPLICATION TO POWER SYSTEMS (ISAP)

Abstract
This paper presents a new proposal for sensor fusion in power system state estimation, analyzing the case of data sets composed of conventional measurements and phasor measurements from PMUs. The approach is based on multiple criteria decision-making concepts. The equivalence of an L-1 metric in the attribute space to the results from a Bar-Shalom-Campo fusion model is established. The paper shows that the new fusion proposal allows understanding the consequences of attributing different levels of confidence or trust to both systems. A case study provides insight into the new model.

2018

Algoritmos Meméticos Aplicados à Identificação de Sistemas e Sintonização de Controladores PID

Authors
Sousa, AL; Vidal, JF; Silva, OF; Freitas, VS;

Publication

Abstract

2018

Hybrid systems control applied to wind power forecasting deviation considering PHS

Authors
Rezende, I; Silva, JM; Miranda, V; Freitas, V; Dias, BH;

Publication
SBSE 2018 - 7th Brazilian Electrical Systems Symposium

Abstract
This paper proposes a methodology using Hybrid Control System (HS) to manage the integration of Variable Renewable Electricity Sources (VRES). The HS define a combination of discrete and continuous signals, in this case, discrete by Pump-Hydro-Storage (PHS) and continuous performance is the Wind Power (WP). The coupling of Wind Power and PHS to produce a dispatchable power output could be a significant benefit to those in an energy trading system. Improving VRES prediction reduces system dispatch errors, however does not give total economic opportunities to the generator. Increased dispatchable backup power generation can improve the system's ability to handle deviations of WP, as verified when the proposed approach is applied to Brazilian and Portuguese power system. © 2018 IEEE.