Companhia Energetica de Minas Gerais CEMIG D

Belo Horizonte, Brazil

Companhia Energetica de Minas Gerais CEMIG D

Belo Horizonte, Brazil

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Diniz A.S.A.C.,Pontifical Catholic University of Minas Gerais | Machado Neto L.V.B.,Pontifical Catholic University of Minas Gerais | De Souza F.M.,Pontifical Catholic University of Minas Gerais | Costa S.C.S.,Pontifical Catholic University of Minas Gerais | And 7 more authors.
2015 IEEE 42nd Photovoltaic Specialist Conference, PVSC 2015 | Year: 2015

This paper presents studies and the implementation of a novel grid-connected PV system with storage. The goal of this project is to validate the operation and to determine the benefits and limitations of integrating storage with grid-connected PV systems. The objective is to evaluate the viability of using complementary electricity storage for meeting the local evening peak demands - night-time peak shaving in a typical load curve of CEMIG's feeder. A novel and versatile control unit-the Bidirectional Intelligent Conversion and Connection Unit (BICC)-has been developed to control the flow of energy from the electricity sources (i.e., PV generator, battery bank, and electric-power grid). In designing this electronic system, we adopted a topology in which the inverter and the maximum power tracking (MPPT) optimize the available power by incorporating two separate and independent converters. In the first phase of the project, a prototype of the system that includes PV with storage and the BICC unit has been installed at GREEN Solar-IPUC in PUC Minas and been under test to evaluate its performance. These trials have been used to optimize system parameters in order to improve the BICC and its interfacing parameters and ensure safe operation of PV-storage system with the grid. This paper reports on the design and advantages of the BICC, the procedures used in the parameter optimization of the prototype, the effectiveness of the BICC in improving the control and connection, conformity to standards, and the viability of scale up for the second phase testing connected to the electric grid (for the utility CEMIG) with storage at the football stadium, Arena do Jacare, located in Sete Lagoas, Minas Gerais. © 2015 IEEE.


Lima A.B.,Federal University of Minas Gerais | Paulino J.O.S.,Federal University of Minas Gerais | Boaventura W.C.,Federal University of Minas Gerais | Lopes I.J.S.,Federal University of Minas Gerais | And 4 more authors.
Electric Power Systems Research | Year: 2015

This work describes a system for measurements of the transient impedance of grounding electrodes using a portable impulse generator and a new arrangement of test leads. The major innovation is the use of a physically short current reaction lead, using a transmission line with very low propagation velocity (2% of the velocity of light). The methodology for obtaining the transient impedance from the measurements is discussed and validated in field studies using a 2.4 m long vertical rod. A comparison with calculated values is also presented. Additionally, the influence of the length of the potential lead is investigated using the very short current lead and the transient soil resistivity is also calculated. © 2014 Elsevier B.V. All rights reserved.


Santos H.L.,Federal University of Minas Gerais | Santos H.L.,Petrobras | Paulino J.O.S.,Federal University of Minas Gerais | Boaventura W.C.,Federal University of Minas Gerais | And 2 more authors.
IEEE Transactions on Power Delivery | Year: 2013

The increase of harmonic current circulation in electric system affects the shunt capacitor banks protection arrangement, causing false alarms and trips and leading to a reduction of the relay sensitivity. This paper analyzes the behavior of the protection system on a reduced-scale model, which reproduces the main features of grounded wye shunt capacitor banks. In such experiments, high levels of current harmonic distortion, voltage unbalance, and bank inherent unbalance were considered. This paper brings experimental analyses for protection arrangements considering robustness and sensitivity. © 1986-2012 IEEE.


Lima A.B.,Federal University of Minas Gerais | Paulino J.O.S.,Federal University of Minas Gerais | Boaventura W.C.,Federal University of Minas Gerais | Guimaraes M.F.,Companhia Energetica de Minas Gerais CEMIG D
2013 International Symposium on Lightning Protection, SIPDA 2013 | Year: 2013

This work describes a system for the measurement of the transient impedance of ground electrodes using a portable impulse generator and a new measuring arrangement. The innovation is the use of a very short current reaction lead, which is possible due to the use of transmission line with very low propagation velocity (3% of the velocity of light). The methodology for obtaining the transient impedance from the measurements is discussed and validated. The experimental results regarding transient impedance measurements for two ground electrodes arrangements are presented. The first arrangement consists of two vertical rods and the second one is an actual 138 kV transmission line tower leg, composed by a vertical electrode in parallel with a horizontal wire. A comparison with calculated values for both cases is also presented. © 2013 IEEE.

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