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+01:00October 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.

Packaging of 10 kV SiC MOSFETs: Trade-Off Between Electrical and Thermal Performances

2020-01-21T15:59:33+01:00October 25th, 2018|Power Electronics & Converters, Publications|

SiC transistors can achieve blocking voltages of 10kV and more. This makes them especially attractive for energy transmission and distribution. Although SiC devices can in theory operate at high temperature (more than 200°C), the on-state resistance of SiC MOSFETs exhibits a strong dependency on the junction temperature. As a consequence, it is shown that these transistors must actually operate at a relatively low junction temperature (less than 100°C) to increase conversion efficiency and prevent thermal runaway. This requirement for high-performance cooling systems has consequences on the packaging technology: the corresponding power modules must both offer a high voltage insulation and a low thermal resistance. In particular, there is a trade-off in the thickness of the ceramic substrate located between the SiC devices and the cooling system. We propose a new substrate structure, with raised features, which improves the voltage strength of a substrate without increasing its thickness. This structure is demonstrated experimentally.

Bruno Luscan’s keynote presentation at EPE’18 ECCE EUROPE is now available online

2018-10-22T17:43:48+02:00October 22nd, 2018|Event|

“POWER GRIDS CONTROL: DRIVERS AND TRENDS” by Bruno Luscan, SuperGrid Institute’s keynote presentation at EPE'18 ECCE EUROPE is now available online!

Energy Control of Modular Multilevel Converters in MTDC Grids for Wind Power Integration

2020-01-21T17:43:59+01:00October 18th, 2018|Publications, Supergrid Architecture & Systems|

The role of Modular Multilevel Converters (MMCs) in HVDC grid greatly differs depending on whether it is an offshore or an onshore station. From the common point in their control schemes, an unexploited ability of the MMC—the controllability of the internally stored energy—is identified in both offshore and onshore applications. The virtual capacitor control, previously proposed by the authors, makes use of this degree of freedom to provide energy contribution to the DC grid. The impact of this control is demonstrated by time-domain simulations of a five-terminal HVDC grid.

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

2019-02-18T09:48:48+01:00October 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+01:00October 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...

Design considerations for the 2- phase cooling system of a 5 MW MVDC converter

2020-01-16T13:32:40+01:00October 11th, 2018|Power Electronics & Converters, Publications|

This presentation will provide an update on our current project: designing a cooler for a high power (5 MW) MVDC converter for offshore wind turbines applications. A number of constraints are imposed, mainly related to a limited volume, environmental, safety and health regulations, and of course cooling performance. Indeed, as we presented last year (ATW 2017), the silicon carbide power semiconductors used in this converter should operate at a junction temperature lower than 100 °C for better efficiency.

CIGRE Young Members organizing a visit at SuperGrid Institute

2018-10-08T14:28:39+02:00October 8th, 2018|Event|

Once a year, CIGRE young members France, organizes industrial, onsite visits where academics, engineers and experts can share and discuss with scholars. This year, SuperGrid Institute has accepted to host this meeting on our premises on the 18th of October 2018.

Measurement and Analysis of SiC-MOSFET threshold voltage shift

2018-10-04T13:19:11+02:00October 4th, 2018|Conference, Power Electronics & Converters|

Gate-oxide technology weakness is a main reliability issue of Silicon Carbide MOSFET transistors. The threshold voltage shift is a critical phenomenon that addresses the reliability of industrial power applications. It is important to have a better understanding of the phenomena implied in the gate threshold voltage shift. In this context, HTGB test is proposed and the resulting gate oxide stress is studied and discussed in this paper.