Switching operations of the disconnecting switch (DS) within high‐voltage gas‐insulated substations generate very fast transient electromagnetic interferences. Fast front pulses induced by these interferences produce high‐level transient currents that can lead to disturbed voltage output of Rogowski coil current transformers (RCTs). Predicting the transient characteristics of RCTs requires the implementation of accurate simulation models of the Rogowski coil. Concentrating on the DS operation process, this paper analyzes the performance of the lumped parameter model (LPM) and the distributed parameter model (DPM) available in the literature by means of comparisons in the time domain and frequency domain between two models, as well as comparisons between simulation results and measurement results in terms of the waveform properties and the distribution of amplitude. It is confirmed that the simulation results based on the DPM show better agreement with the measurements than those based on the LPM. It is also indicated that the maximum amplitude of the RCT output is approximately 580 mV with the dominant frequency of 2 MHz during the fast transient. © 2018 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Modulation of the electric potential on a conducting electrode is presented to generate an optical contrast for scattering microscopy that is sensitive to both surface charge and local topography. We dub this method electric-double-layer-modulation microscopy. We numerically compute the change in the local ion concentration that is the origin of this optical contrast for three experimentally relevant geometries: nanosphere, nanowire, and nanohole. In absence of plasmonic effects and physical absorption, the observable optical contrast is proportional to the derivative of the ion concentration with respect to the modulated potential. We demonstrate that this derivative depends on the size of the object and, less intuitively, also on its surface charge. This dependence is key to measuring the surface charge, in an absolute way, using this method. Our results help to identify the experimental conditions such as dynamic range and sensitivity that will be necessary for detecting the elementary charge jumps. We conclude that the nanohole is the most suitable geometry of the three for achieving elementary charge sensitivity.

Electromagnetic active suspension system is considered to have improved stability and better dynamic response, compared to the hydraulic active suspension system. To investigate the influence of suspension parameters on system characteristics, the frequency response of quarter vehicle model is analyzed through Bode plots by varying the spring stiffness and damping coefficient. The sprung mass acceleration, suspension deflection and tire deflection are investigated respectively. This paper proposes a novel electromagnetic suspension system, comprising of a linear switched reluctance motor (LSRM) and a passive spring. The mechanical and electrical characteristics of the proposed linear motor are obtained and verified by using two-dimensional finite element method (FEM). The magnetic flux densities at specific translator positions are demonstrated. In order to study the feasibility and evaluate the performance of the proposed suspension system, a LQR optimal controller is developed and simulated with the quarter-vehicle model. The sprung mass acceleration, suspension deflection and related force applied by the actuator are investigated under different road disturbance. Both frequencies of disturbance are approximate to the suspension natural frequencies, which are the most severe working point of active suspension system. Simulation results demonstrate that good dynamic response and better ride comfort can be achieved by the proposed active suspension system.

Unrestricted particle transport through microfluidic channels is of paramount importance to a wide range of applications, including lab-on-a-chip devices. In this article, we study using video microscopy the electro-osmotic aggregation...