Protective System of a Residential Building: Triggered-Lightning ... lic cable.Lightning current was injected into the lightning protective system ground rod, and ...
Stationary Batteries
Switchgear
Dynamical Models of Lead-Acid Batteries: Implementation Issues
Transient Recovery Voltages Requirements for System Source Fault Interrupting by Small Generator Circuit Breakers Dufournet, D.; Montillet, G.E
Barsali, S.; Ceraolo, M. Author Affiliation: University of Pisa, Italy Abstract: This paper explains how the lead-acid models described previous paper can be utilized in practice. That paper does not supply detailed information on how to identify the several parameters of the proposed models, and it defines a whole family of models, but does not discuss which model of the family is adequate for a given purpose. These two issues are tackled in this paper. For the first, more complex issue, two options are proposed and discussed: a complete identification procedure involving extensive lab tests and a simplified one that combines information from lab tests and data supplied by the manufacturer. Further simplifications applicable in case of batteries belonging to the same family are presented. Preprint Order Number: PE-637EC (11-2001) Discussion Deadline: April 2002
Surge Protective Devices Direct Lightning Strikes to the Lightning Protective System of a Residential Building: Triggered-Lightning Experiments
Author Affiliation: ALSTOM Research Center, ALSTOM Power Transmission Abstract: Recent years have seen an increasing development of small generations of electric power. These generators of relatively low power, equal to or less than 100 MVA, are protected in an economic way by generator circuit breakers that are located between the generator and the step-up transformer. In 1997 the IEEE Switchgear Committee has issued a new edition of its standard C37-013 for generator circuit breakers, which covers mainly the applications with power transformers rated 100 MVA and above [1]. A revision of this standard is currently prepared by the IEEE Switchgear Committee in order to broaden its scope to all generator circuit breakers. The purpose of this paper is to contribute to the definition of TRV requirements for system-source faults in the case of small generator circuit breakers connected to the step-up transformer by cables. Keywords: ac high-voltage generator, generator circuit breakers. Preprint Order Number: PE-018PRD (11-2001) Discussion Deadline: April 2002
Transformers
Evolving Wavelet Networks for Rakov, V.A.; Uman, M.A.; Fernandez, M.I.; Mata, C.T.; Rambo, Power Transformer Condition Monitoring Kj.; Stapleton, M.V; Sutil, R.R. Huang, YC.; Huang, C.M. Author Affiliation: University of Florida, Gainesville, FL Abstract: Lightning triggered from natural thunderclouds using the Author Affiliation: Cheng Shiu Institute of Technology; Kun Shan rocket-and-wire technique was employed in order to subject to direct University of Technology lightning strikes the lightning protective system of a test house at the InAbstract: This paper proposes a novel model for power transformer temational Center for Lightning Research and Testing (ICLRT) at condition monitoring using evolving wavelet networks (EWNs). The Camp Blending, Florida. The electrical circuit of the test house was EWNs are three-layer structures, which contain wavelet, weighting, and connected to the secondary of a padmount distribution transformer lo- summing layers. The EWNs automatically adjust the network paramecated a distance of about 50 m from the house. The transformer primary ters, translation, and dilation in the wavelet nodes and the weighting valwas connected to a 650-m long unenergized underground power cable. ues in the weighting nodes, through an evolutionary-based optimization The test house had two ground rods, one for the lightning protective process. Global search abilities of the evolutionary algorithm as well as system grounding and the other for the power supply system ground- the multiresolution and localization natures of the wavelets enable the ing. The two rods were about 3 m apart and were connected by a metal- EWNs to identify the complicated, numerical-knowledge relations of lic cable. Lightning current was injected into the lightning protective dissolved gas contents in transformer oil to corresponding fault types. system ground rod, and the currents and voltages at different points in The proposed EWNs have been tested on the Taipower Company diagthe test system were measured. The waveshapes of currents in the nostic records and compared with the fuzzy diagnosis system, artificial ground rods of the test house differed markedly from the current neural networks as well as the conventional method. The test results rewaveshapes in other parts of the overall system. The ground rods at the veal that the EWNs possess far superior diagnosis accuracy and require test house appeared to filter out the higher-frequency components of less constructing time than the existing methods. the lightning current, allowing the lower-frequency components of the Keywords: Fault diagnosis, power transformers current to enter the house's electrical circuit; that is, the ground rods apPreprint Order Number: PE-283PRD (11-2001) peared to exhibit a capacitive behavior rather than the often expected Discussion Deadline: April 2002 resistive behavior. This effect was observed for dc grounding resistances of the rods (driven in sandy soil with conductivity of about 2.5 x 10-4S/m) ranging from more than a thousand Q to some tens of Q. A Novel Autotransformer Design The peak values of (1) the current entering the test house's electrical Improving Power System Operation circuit, (2) the current flowing to the distribution transformer secondary Andrei, R.G.; Rahman, M.E.; Koeppel, C.; Arthaud, J.P neutral, and (3) the current flowing through the surge protective devices Author Affiliation: American Electric Power, Columbus, OH; at the test house's service entrance were observed to be greater than in either of the two scenarios suggested by the International Jeumont Schneider Transformateurs Electrotechnical Commission. Abstract: This paper presents some of the design and operational Keywords: Lightning, ground rods, lightning protective system, aspects of a novel autotransformer design, which allows modifying the active power flow through the unit. The system performance of a surge protective devices. Preprint Order Number: PE-032PRD (11-2001) three-phase 675 MVA, 345/138 kV voltage class autotransformer of this design is discussed. Discussion Deadline: April 2002 IEEE Power Engineering Review, February 2002
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