Searched for: collection%253Air
(1 - 15 of 15)
document
Shekhar, A. (author), Soeiro, Thiago B. (author), Ramirez Elizondo, L.M. (author), Bauer, P. (author)
During the operation of a three line ac link in parallel with a ac-dc-ac link system that employs Back-to-Back (B2B)Medium Voltage Modular Multilevel Converters (MMC), a path for the low frequency zero sequence currents is shown to exist. Apart from causing additional losses, these currents can result in limitations on power capacity. A...
conference paper 2019
document
Shekhar, A. (author), Feng, X. (author), Hebner, R. (author), Gattozzi, A. (author), Strank, S. (author), Mor, A. R. (author), Ramirez Elizondo, L.M. (author), Bauer, P. (author)
The thermal behavior of medium voltage dc cables can find useful applications for efficient and capacity enhanced operation in cities as well as compact power transmission on all electric ships. Concepts such as dynamic current and voltage rating, difference in thermal proximity in ac and dc operation, pulsed load application and thermal...
conference paper 2018
document
Liu, Zhihao (author), Shekhar, A. (author), Ramirez Elizondo, L.M. (author), Bauer, P. (author)
Localization of series arc faults in dc microgrids is an important requirement to guarantee operational safety and uninterrupted power to end users. In the previous EPE-ECCE proceeding, a theoretical proof was provided for the selective series arc detection using a novel algorithm. In the current paper, the concept is validated by showcasing...
conference paper 2017
document
Shekhar, A. (author), Kontos, E. (author), Ramirez Elizondo, L.M. (author), Bauer, P. (author)
A practical issue faced by today's ac grid is the rapidly growing power demand on its aging infrastructure. One possibility to maximize the capacity of the existing infrastructure is to refurbish the ac links to operate under dc conditions using modular multilevel converters. In this paper, the idea is applied to restructure an actual medium...
conference paper 2018
document
Shekhar, A. (author), Ramirez Elizondo, L.M. (author), Bauer, P. (author)
Since shipboard power systems are inherently islanded and consist of energy intensive sources and loads, it is an interesting application for dc microgrids. The object of this paper is to explore the merits of dc based shipboard power distribution as compared to conventional ac solutions. A survey of current initiatives, emerging concepts and...
conference paper 2017
document
Liu, Zhihao (author), Shekhar, A. (author), Ramirez Elizondo, L.M. (author), Bauer, P. (author)
This paper provides an empirical study on series arc behavior in low voltage dc microgrids. The response of an R-L-C dc microgrid abstraction towards series arcs is studied experimentally for varying grid inductance, dc voltages, load capacitances and load currents. In order to account for the stochastic nature of arcs, experiments are...
conference paper 2017
document
Shekhar, A. (author), Ramirez Elizondo, L.M. (author), Bauer, P. (author)
The role of MVDC links for distribution network expansion is important. The distribution network operators (DNOs) can maximize the power transfer capacity of existing grid infrastructure during (n-1] contingencies using reconfigurable parallel ac-dc architecture. In addition this concept involves a range of efficiency, reliability and...
conference paper 2018
document
Shekhar, A. (author), Ramirez Elizondo, L.M. (author), Qin, Z. (author), Bauer, P. (author)
Back-to-back Modular multilevel converters (MMC) for medium voltage dc (MVDC) distribution link applications offer exciting opportunities due to its superior harmonic performance and high efficiency. Based on the steady state equations, it is shown that under specific active and reactive power operation, an increase in dc link voltage can be...
conference paper 2018
document
Shekhar, A. (author), Soeiro, Thiago B. (author), Qin, Z. (author), Ramirez Elizondo, L.M. (author), Bauer, P. (author)
An important step in Voltage-Source Modular Multilevel Converter (MMC) design is the selection of adequate semiconductor blocking voltage class. This paper highlights that particularly for grid connected medium voltage applications, the choice of suitable switch blocking voltage class is not so straightforward. The market available switch...
conference paper 2018
document
Shekhar, A. (author), Ramirez Elizondo, L.M. (author), Soeiro, Thiago B. (author), Bauer, P. (author)
Hybrid ac–dc reconfigurable link technology can find interesting applications in medium-voltage power distribution. These are networks having dc links operating in parallel alongside ac links with post-fault reconfiguration capability. A given system can operate in different configurations while maintaining equivalent capacity during (n−1)...
journal article 2020
document
Shekhar, A. (author), Kontos, E. (author), Ramirez Elizondo, L.M. (author), Mor, A. R. (author), Bauer, P. (author)
It is anticipated that with the thrust towards use of clean energy resources such as electric vehicles, future distribution grids will face a steep increase in power demand, forcing the utility operators to invest in enhancing the power delivering capacity of the grid infrastructure. It is identified that the critical 5–20 km medium voltage (MV)...
journal article 2017
document
Shekhar, A. (author), Feng, Xianyong (author), Gattozzi, Angelo (author), Hebner, Robert E. (author), Wardell, Douglas (author), Strank, Shannon (author), Mor, A. R. (author), Ramirez Elizondo, L.M. (author), Bauer, P. (author)
A scientific consensus is emerging on the benefits of direct current (DC) distribution in medium voltage (MV) power systems of ships and cities. At least 50% space savings and increased power transfer capacity are estimated with enhanced voltage DC operation of electric cables. The goal of this research is to contribute to developing the...
journal article 2017
document
Shekhar, A. (author), Ramirez Elizondo, L.M. (author), Feng, Xianyong (author), Kontos, E. (author), Bauer, P. (author)
While the scientific community recognizes the benefits of DC power transfer, the distribution network operators point out the practical and economic constraints in refurbishing the existing AC network at a medium-voltage level. Some apprehensions like reliability, cost of ownership, and safety in adopting a universal DC distribution may merit...
journal article 2018
document
Shekhar, A. (author), Soeiro, Thiago B. (author), Ramirez Elizondo, L.M. (author), Bauer, P. (author)
Hybrid ac-dc distribution systems with multiple parallel operating ac and dc links are being developed to maximize system capacity during (n-1) contingencies. This paper shows that offline reconfigurability between such ac and dc links post-fault clearance allows an additional design flexibility of reducing the required substation converter...
journal article 2020
document
Shekhar, A. (author), Ramirez Elizondo, L.M. (author), Bandyopadhyay, S. (author), Mackay, L.J. (author), Bauer, P. (author)
Low voltage dc distribution grids face issues associated with arc faults, aggravated by the absence of current zero crossing. The focus of this paper is to comprehensively develop a method of series arc fault detection at the load side power electronics, based on the electrode dependent initial voltage drop occurring at the arc initiation....
journal article 2018
Searched for: collection%253Air
(1 - 15 of 15)