We performed a metrological characterization of the quantum Hall resistance in a $1\mu \text{m}$ wide graphene Hall bar. The longitudinal resistivity in the center of the $\nu =\pm 2$ quantum Hall plateaus vanishes within the measurement noise of $20\text{m}\Omega$ up to $2\mu \text{A}$ . Our results show that the quantization of these plateaus is within the experimental uncertainty (15 ppm for $1.5\mu \text{A}$ current) equal to that in conventional semiconductors. The principal limitation of the present experiments is the relatively high contact resistances in the quantum Hall regime, leading to a significantly increased noise across the voltage contacts and a heating of the sample when a high current is applied.

The exponential increase in Global greenhouse gas (GHG) emissions and the rapid depletion of fossil fuels over the past few decades have swayed the transportation sector toward becoming more electric. In the last decade, with continuous improvements in battery technology and interfacing power electronics, there has been immense progress in the electrification of land-based transport. As their electrification gains pace, the focus is shifting toward greening other forms of transport, such as maritime and aviation sectors, since they contribute substantially to the total carbon footprint. The marine sector has witnessed huge growth in recent years because of the development of international trade, wherein it plays an essential role in the transportation of goods across the globe. The variation in ship sizes, types, and routes—along with their grid-distant nature and water-borne operation—distinguishes them from terrestrial electric vehicles. This gives rise to a multitude of unique challenges on board as well as at the ports that they operate around. Power electronics is one of the key enabling technologies in tackling these challenges and thereby creating safe, reliable, and emission-free maritime transport.

Due to their superior material properties, wide bandgap (WBG) semiconductors enable the application of power electronics at higher temperature operation, higher frequencies, and higher efficiencies compared to silicon (Si). However, the commonly-used aluminum wire bonding as topside interconnection technology prevents WBG semiconductors from reaching their full potential, due to inherent parasitic inductances, large size, heat dissipation, and reliability issues of wire bonding technology. Therefore, this article presents a comprehensive review of topside interconnection technologies of WBG semiconductor power devices and modules. First, the challenges and driving factors for the interconnection of WBG semiconductor dies are discussed. Second, for each widely commercially used WBG semiconductor, i.e., silicon carbide and gallium nitride, technical details and innovative features of state-of-the-art interconnection techniques in packages are reviewed. Then, the majority of existing topside interconnection materials for WBG semiconductors are categorized and compared, followed by a discussion of their advantages, challenges, and failure modes. Based on this elaborate discussion, potential future directions of the interconnection technology development are given. It is concluded that the superior performance of WBG semiconductors can be obtained by combining novel materials with innovative designs for the topside interconnections.

A new method is developed for synchrophasor-based estimation of three-phase transmission line (TL) impedance parameters, applicable for both fully transposed and untransposed TLs. The method is based on accurate time-synchronized measurements of the voltage and current phasors at both ends of a TL. The method estimates the line impedance values using a robust estimator with the property that the influence of outliers on the final results is minimized. A robust estimator is chosen as an alternative to well-known ordinary least-squares estimators which are highly sensitive to outliers. The performance of the method has been evaluated using a laboratory setup simulating real power system conditions. The necessary conditions for algorithm convergence as well as the requirements for measurement accuracy have been studied. In addition, this paper describes validation results of the proposed method in real high-voltage power system conditions by measuring voltage and current phasors with two phasor measurement units installed on both terminals of a 400-kV fully transposed overhead TL.

We report the experimental observation of a discontinuous change in slope at ${\mathit{T}}_{\mathit{c}}$ of the temperature dependence of the work function of ${\mathrm{YBa}}_2$ ${\mathrm{Cu}}_3$ ${\mathrm{O}}_{7\mathrm{-}\mathrm{\delta }}$. We interpret this effect as a superconductivity-induced temperature dependence of the chemical potential. Using a general thermodynamic relation for second-order phase transitions and published values of the specific heat jump, we extract a value for d ln${\mathit{T}}_{\mathit{c}}$/dn, with n the charge carrier density. This value is consistent with hole-type superconductivity.

Grid operators are facing a significant challenge in ensuring continuity and quality of electricity supply, while more and more renewable energy sources are connected to the grid. The resulting evolvement of so-called smart grids strongly relies on the availability of reliable measurement data for monitoring and control of these grids. This paper presents an overview of the results achieved in recent smart grid metrology research in Europe, aiming to realize the required metrology infrastructure for ensuring security and quality of supply in future smart electrical grids. A consortium of 22 metrology and research institutes has made significant steps in modeling of smart grids, enhancement of the revenue metering infrastructure, performance and evaluation of onsite power quality campaigns, and the development of a metrological framework for traceability of smart grid phasor measurements.