Overview of DC–DC Converters Dedicated to HVdc Grids

2019-02-19T10:05:13+00:00February 19th, 2019|Power Electronics & Converters, Publications, Supergrid Architecture & Systems|

This paper presents an overview of the dc–dc power converters dedicated to HVdc proposing a classification based on their structure. Two large families are established: those which provide galvanic isolation, and those which do not. Several subfamilies are also proposed. An overview of the main HVdc applications that can be targeted with each family is also presented, highlighting the main converter requirements for each application case.

25 kV-50 Hz railway power supply system emulation for Power-Hardware-in-the-Loop testings

2019-01-08T10:53:47+00:00January 8th, 2019|Power Electronics & Converters, Publications|

This paper presents a methodology to consider the impedance of a grid in power hardware in the loop (PHIL) experiments to validate power converter control in presence of harmonics or resonances in the network impedance. As the phenomena to emulate are in a large frequency range, the skin effect in conductors has to be taken into account. A procedure is developed to model the network.

Modelling of a 25 kV-50 Hz railway infrastructure for harmonic analysis

2019-02-18T11:42:11+00:00December 20th, 2018|Power Electronics & Converters, Publications|

This paper presents a methodology for the modelling of a 25 kV-50 Hz railway infrastructure, for frequencies from 0 to 5 kHz. It aims to quantify the amplifications of current and voltage harmonics generated by on-board converters into the infrastructure. A circuit is developed to model the skin effect in the overhead line for time-domain simulations. A new approach, based on state space representation and transfer functions, is also proposed to analyse the interactions between trains.

Study of Turn-to-Turn Electrical Breakdown for Superconducting Fault Current Limiter Applications

2018-11-06T16:01:51+00:00November 2nd, 2018|High Voltage Substation Equipment, Publications|

The rational insulation design of a resistive superconducting fault current limiter (r-SCFCL) requires data gathered from experimental setups representative of the final apparatus. Therefore, an experimental study was performed to characterize the electrical breakdown (BD) of liquid nitrogen (LN2) in the peculiar conditions of a quenching superconducting device.

Arc appearance and cathode spot distribution in a long gap high-current vacuum arc controlled by an external axial magnetic field

2018-11-15T16:33:23+00:00October 31st, 2018|High Voltage Substation Equipment, Publications|

An experimental study of a high-current vacuum arc (VA) generated between two static CuCr25 contacts spaced 20 or 30 mm apart was conducted to characterize the arc appearance and the cathode spot (CS) distribution.

HVDC protection criteria for transient stability of AC systems with embedded HVDC links

2019-02-18T09:48:48+00:00October 15th, 2018|Publications, Supergrid Architecture & Systems|

The objective of this study is to propose a methodology for the transient stability assessment of a simple but representative AC grid in case of DC fault. After validation of the methodology, some HVDC link protection criteria are defined in terms of the Critical Time to Return to Operation. These criteria will be helpful for the design of HVDC protection systems or for the sizing of future HVDC links in order to respect the constraints of the existing protection strategies.

Electrical properties of epoxy systems based on ionic liquids

2018-11-07T16:13:21+00:00October 12th, 2018|High Voltage Substation Equipment, Publications|

In accordance with their interesting properties, ionic liquids (ILs) have attracted in the recent years a great interest in the material field. Recently, few authors have demonstrated the reactivity of ionic liquids towards epoxy in order to form new epoxy-based networks...