Geraldo F. Burani

Evaluation at field of aged 345kV class ZnO surge arresters

This research aimed at developing a technique for field evaluation of aged 345kV ZnO surge arresters, for identifying suspect equipment with in service failure risk. In this way, material damages, emergency downtime periods and personal hazards could be avoided. After some in service failures in 345kV class ZnO arresters, the analysis of the failed equipment showed burning signs at the ZnO blocks surface inside the failed arrester, probably caused by internal superficial electrical discharge. The surface coating of the ZnO blocks, under high electrical gradient, seemed to have suffered some kind of burning process, in this way creating conductive paths, causing short-circuit and leading to failure. The technique developed in this research was applied successfully in the field, in substation environment, where the identification of surge arresters presenting internal partial discharges activity was possible. All the tests were performed with surge arresters under normal operation with all installation energized.

Calibration of High Voltage Transducers for Power Quality Measurements in Electric Networks

The term power quality is, in general, closely related to the quality of the voltage. Considering the widespread presence of sensitive loads in the electric grid, and the increasing awareness of the consumers concerning the quality of the power supply, the control and measurement of power quality parameters regarding harmonics, interharmonics, sags, swells, and others are increasingly becoming much more important. Most of the necessary calibration procedures for power quality monitors and power quality analyzers are already defined in the international standards, mainly in the IEC 61000 series (IEC, 1995) and ANSI/IEEE Standards. This chapter presents results of a research which aimed to develop a methodology for the calibration of high voltage transducers for power quality measurements in high voltage networks, considering that such kind of procedures have not been established in the pertinent standards yet (Bradley et al., 1985; Seljeseth et al., 1998). In this research it is also considered that the conventional high voltage laboratory is not suitable for power quality tests. Thus, some improvements are needed regarding such matter. In this development, modelling and computer simulation using ATP – Alternative Transients Program (ATP, 1987) were used to assess both the frequency response of the test setup, and the design of the reactive compensation of the test circuit.

Capacity of carrying lightning currents in LPS copper cables and connectors experimental verifications

This paper presents the results of a series of tests on patches of bare copper cable, usually used in LPS to check their ability to conduct lightning currents.

Risk analysis associated to lightning in oil refinery construction sites

This work presents a study on plant and workers protection against direct lightning in oil refineries construction sites. Since these sites have large and free open air areas, workers are exposed to direct lightning strokes. This study analyzes each structure calculating the risks based on recommendations of the standard IEC 62305-2/2006 [1]. Moreover, it defines both the structure protection volumes using the rolling sphere method, and the protection systems against lightning for each structure using natural components or not.

Testing Forecasting Method:Displacement of Bottled LPG by Pipelined Gas in the Brazilian Dwelling Sector, a 2004Essay Revisited

Thecompetition between two energy sources for the same market which results in the replacement of one source by the other, based on dynamic model derived from biomathematics, previously applied in 2004, by authors in the Brazilian LPG x Pipelined NG (PNG)dwellingconsumption market is analyzed. The proposed model seems to be useful to increase the knowledge of the relationship between input and output variables in a system and the results can improve the communication rapport between theoretical modelers and decision makers.The forecasting results are compared with the actual data.

Experimental verifications of direct lightning protection in flammable liquid storage tanks: Cases of carbon-steel and aluminum geodesic domes

This paper presents experimental and theoretical results of laboratory tests concerning the simulations of continuing current effects from typical cloud-ground lightning. The tests were carried out from High Power Laboratory of Institute of Energy and Environment of University of Sao Paulo. Carbon-steel and aluminum plates from the cover of geodesic domes of a typical tank were used in the tests. Results of the tests are presented considering several conditions, as well as their theoretical results, which were compared with those values presented in the main references dealing with related subjects, such as plates used in aircraft.

Developing a worksheet for risk analysis according to ABNT NBR 5419-2

This paper presents development of a spreadsheet for risk analysis and an app for smartphone in order to aid this analysis.

The new ABNT NBR 5419: Lightning protection: Differences between the new Brazilian standard and IEC 62305

This paper presents the main differences between the new coming version of the Brazilian Standard on Lightning Protection ABNT NBR 5419 and IEC 62305 series, on which the Brazilian Standard is based.

Effects of lightning in oil plants construction sites — Step and touch voltage simulation and tests in work footwear

This paper presents a study on the effects caused by indirect lightning on oil refinery construction site workers. We made some tests on work footwear, commonly used by workers in these refineries, and some simulations for a specific site for the evaluation of step and touch voltages.