Safe Engineering Services and Technologies Ltd

Montréal, Canada

Safe Engineering Services and Technologies Ltd

Montréal, Canada
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Ladan S.,Safe Engineering Services and Technologies Ltd. | Aghabarati A.,Safe Engineering Services and Technologies Ltd. | Moini R.,Safe Engineering Services and Technologies Ltd. | Fortin S.,Safe Engineering Services and Technologies Ltd. | Dawalibi F.P.,Safe Engineering Services and Technologies Ltd.
2016 33rd International Conference on Lightning Protection, ICLP 2016 | Year: 2016

The shielding effectiveness of a metallic enclosure with multiple openings sited close to a transmission line tower hit by lightning is investigated, both in the frequency domain and in the time domain. Two scenarios are analyzed to define the possible sources of interference. First, the entire power network including the tower hit by lightning, shield wires and phase conductors is considered. Next, the simplified case of a single tower hit by lightning is investigated. The results reveal that for a better protection of equipment against lightning, the entire power network should be considered as source of interference for the study of shielding effectiveness. © 2016 IEEE.


Dawalibi F.P.,Safe Engineering Services and Technologies Ltd | Tee S.,Safe Engineering Services and Technologies Ltd | Fortin S.,Safe Engineering Services and Technologies Ltd | Grignon N.,Hydro - Quebec
IEEE Transactions on Power Delivery | Year: 2011

The industry-standard IEEE C37.99-2000 recommends the use of Peninsula Neutral Ground as the preferred method to ground the neutrals of capacitor banks in high-voltage substations. The basis for this recommendation is a 1972 IEEE paper by Rogers and Gillies that has remained unchallenged until now. Many grounding designs are carried out according to this approach despite the fact that it is the least efficient one. As long as this IEEE standard is not updated to reflect the new findings reported in this paper, designers will continue to be misguided. In this paper, we demonstrate that IEEE standard C37.99-2000 recommendations have no valid scientific basis by comparing the overall performance of a 735/230-kV substation grounding system designed according to the Peninsula Neutral Ground method, the single-point neutral ground and a more conventional design consisting of reasonably dense ground conductors in the 230-kV capacitor banks area and conclude that the conventional design offers superior performance from a safety and electromagnetic-interference perspective based on the fundamental frequency and full frequency spectrum of the back-to-back capacitor switching transient current discharge. © 2010 IEEE.


Aghabarati A.,Safe Engineering Services and Technologies Ltd. | Moini R.,Safe Engineering Services and Technologies Ltd. | Ladan S.,Safe Engineering Services and Technologies Ltd. | Fortin S.,Safe Engineering Services and Technologies Ltd. | Dawalibi F.P.,Safe Engineering Services and Technologies Ltd.
IEEE International Symposium on Electromagnetic Compatibility | Year: 2016

The shielding performance of new spherical polyhedral structures illuminated by an electromagnetic plane wave is investigated. The spherical shield screens consist of a juxtaposition of wire conductors and metallic screens distributed according to the regular pattern of a spherical polyhedron. It is shown that at low frequency, the wire frame screen provides high levels of shielding effectiveness, while its counterpart of metallic surfaces has a similar behavior for higher frequency bands. Moreover, the shielding characteristics of a combined wire-surface spherical surface are reported and compared with the cases of a single screen of wire conductors or metallic surfaces. The reported numerical results illustrate the advantage of using the combined configuration. It is observed that the combined wire-surface spherical screen can be designed in order to be effective simultaneously against interference at the low and high frequency limits for any polarization of the incident field. © 2016 IEEE.


Ladan S.,Safe Engineering Services and Technologies Ltd. | Aghabarati A.,Safe Engineering Services and Technologies Ltd. | Moini R.,Safe Engineering Services and Technologies Ltd. | Fortin S.,Safe Engineering Services and Technologies Ltd. | Dawalibi F.P.,Safe Engineering Services and Technologies Ltd.
IEEE International Symposium on Electromagnetic Compatibility | Year: 2016

This article discusses the safety issues related to electrostatic discharge phenomena caused by electric field induction from high voltage transmission lines. The main objective is to evaluate the inducing effects of an overhead line including towers and grounding networks on a nearby vehicle. Two different cases are considered. The first case studies the network under steady-state conditions while the second case treats a tower subjected to a single phase to ground fault. In both cases the induced current discharged from the vehicle to the ground is evaluated in order to define a severity index that is used to determine the location of the unsafe zones around the tower structure. © 2016 IEEE.


Ma J.,Safe Engineering Services and Technologies Ltd. | Dawalibi F.P.,Safe Engineering Services and Technologies Ltd.
Asia-Pacific Power and Energy Engineering Conference, APPEEC | Year: 2012

The effect of backfill on the performance of the grounding system of a substation is studied in this paper. The backfill is simply the replacement of the existing soil surrounding the grounding grid with a different soil. When the backfill soil resistivity is higher than the original soil resistivity, the touch voltage is higher compared with the case where no backfill is used; the step voltage can also be slightly higher. When the backfill soil resistivity is lower than the original soil resistivity, the touch voltage is lower compared with the case where no backfill is used but the step voltage is significantly higher. An approximate method for modeling the backfill in a multilayer soil is also presented. © 2012 IEEE.


Southey R.D.,Safe Engineering Services and Technologies Ltd. | Siahrang M.,Safe Engineering Services and Technologies Ltd. | Fortin S.,Safe Engineering Services and Technologies Ltd. | Dawalibi F.P.,Safe Engineering Services and Technologies Ltd.
IEEE Transactions on Industry Applications | Year: 2015

When measuring the ground impedance of an electrically isolated grounding system, it sometimes happens that the test electrodes are placed at considerably greater distances from the installation under test than the maximum electrode spacing used during the soil resistivity measurements carried out during the predesign phase of the grounding system. As a result, ground impedance measurements carried out with the fall-of-potential method may contain valuable supplemental information about deep soil strata that can improve grounding system performance predictions made during the design phase with computer modeling software and explain discrepancies encountered between predicted and measured ground impedance values. These data can be also used during subsequent grounding design work associated with facility expansion. It is shown in this paper how, in the absence of interfering metallic infrastructure, such ground impedance measurements can be converted into apparent soil resistivity values corresponding to deeper soil layers, with an example showing how dramatic improvements in grounding system performance predictions can be obtained. © 1972-2012 IEEE.


Zhao H.,Safe Engineering Services and technologies Ltd. | Fortin S.,Safe Engineering Services and technologies Ltd. | Dawalibi F.P.,Safe Engineering Services and technologies Ltd.
IEEE Transactions on Industry Applications | Year: 2015

This paper presents the analysis of grounding systems including freely oriented conductors and metallic plates of arbitrary shapes in horizontal multilayer soils. The analysis method yields not only the scalar potential but also the electric field and current density in the soil in the low frequency limit. Numerical results are provided for various configurations such as a single plate, a plate with rods, parallel plates, a box, or cylinders formed by multiple plates and are verified against available analytical methods. © 1972-2012 IEEE.


Hajiaboli A.,Safe Engineering Services and Technologies Ltd. | Fortin S.,Safe Engineering Services and Technologies Ltd. | Dawalibi F.P.,Safe Engineering Services and Technologies Ltd.
IEEE Transactions on Industry Applications | Year: 2015

This paper presents an analysis of high-voltage direct current sea electrodes using different numerical techniques. The large volume of sea water that must be included in the analysis is represented using infinite (inclined layer model) and finite models (finite volume and hemispheroidal models). The comparison between the results obtained using these models is based on the potential rise of the electrode, the sea potential rise in the vicinity of the electrode, and the computational burden for utilizing each model. The analysis shows that the results obtained using finite models can predict the performance of the electrode more accurately and realistically. © 1972-2012 IEEE.


Fortin S.,Safe Engineering Services and Technologies Ltd. | Mitskevitch N.,Safe Engineering Services and Technologies Ltd. | Dawalibi F.P.,Safe Engineering Services and Technologies Ltd.
IEEE Transactions on Industry Applications | Year: 2015

This paper presents a theoretical model for the analysis of grounding systems located in multilayer soils in which arbitrary heterogeneities (finite volumes) are embedded. The presence of the heterogeneities is handled through a boundary element method, whereas that of the horizontal soil layers is analytically handled using image theory (or any other equivalent technique). Numerical results are presented for several cases and are shown to agree with limiting cases. The results also clearly show that the presence of finite heterogeneities in multilayer soils can have a very strong impact on the safety performance of a grounding system. © 1972-2012 IEEE.


Liu J.,Safe Engineering Services and Technologies Ltd. | Dawalibi F.P.,Safe Engineering Services and Technologies Ltd.
Proceedings - International Conference on Future Power and Energy Engineering, ICFPEE 2010 | Year: 2010

The design of a wind farm grounding system including the substation and wind turbine generators of the collector network is a very comprehensive task. Powerful integrated grounding simulation methods and design techniques that are appropriate for carrying out this kind of work are presented and discussed in this paper. They include soil structure model selection based on in-situ soil resistivity test data, current distribution calculations for phase-to-ground faults at the substation and wind turbines, design of the substation and wind turbine grounding systems and safety evaluations of the grounding systems. The methods and techniques presented in this paper can be used as a reference guide when designing grounding systems of a large wind farm network. © 2010 IEEE.

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