Calculation of MoM interaction integrals in highly conductive media

The construction of the impedance matrix in the method of moments requires the calculation of interaction integrals between the expansion functions, through the Green's function and its derivatives. The singular behavior of the Green's function poses considerable problems for an accurate numerical evaluation of these integrals, requiring techniques such as singularity extraction or cancellation. In this contribution we will show why these methods fail when the medium is highly conductive. A novel technique is proposed to handle these highly challenging integrals. The complexity of the new method is independent of the conductivity

Entire domain basis function expansion of the differential surface admittance for efficient broadband characterization of lossy interconnects

This article presents a full-wave method to characterize lossy conductors in an interconnect setting. To this end, a novel and accurate differential surface admittance operator for cuboids based on entire domain basis functions is formulated. By combining this new operator with the augmented electric field integral equation, a comprehensive broadband characterization is obtained. Compared with the state of the art in differential surface admittance operator modeling, we prove the accuracy and improved speed of the novel formulation. Additional examples support these conclusions by comparing the results with commerical software tools and with measurements

Power quality and electromagnetic compatibility: special report, session 2

The scope of Session 2 (S2) has been defined as follows by the Session Advisory Group and the Technical Committee: Power Quality (PQ), with the more general concept of electromagnetic compatibility (EMC) and with some related safety problems in electricity distribution systems. Special focus is put on voltage continuity (supply reliability, problem of outages) and voltage quality (voltage level, flicker, unbalance, harmonics). This session will also look at electromagnetic compatibility (mains frequency to 150 kHz), electromagnetic interferences and electric and magnetic fields issues. Also addressed in this session are electrical safety and immunity concerns (lightning issues, step, touch and transferred voltages). The aim of this special report is to present a synthesis of the present concerns in PQ&EMC, based on all selected papers of session 2 and related papers from other sessions, (152 papers in total). The report is divided in the following 4 blocks: Block 1: Electric and Magnetic Fields, EMC, Earthing systems Block 2: Harmonics Block 3: Voltage Variation Block 4: Power Quality Monitoring Two Round Tables will be organised: - Power quality and EMC in the Future Grid (CIGRE/CIRED WG C4.24, RT 13) - Reliability Benchmarking - why we should do it? What should be done in future? (RT 15

Performance Evaluation of a Full-Scale Deep U-Tube Utilizing Ozonated Oxygen as the Process Gas for Treating Drinking Water

A deep U-tube for treating drinking water is composed of a coaxial inner tube serving as an efficient concurrent down-flow ozone dissolver and an outer column carrying out reactions between ozone and organic substances dissolved in the water after sedimentation treatment. In the present study, we developed a novel simulation model of the U-tube reactor, assuming that the U-tube is composed of a plug flow section (inner tube) followed by a tanks-in-series section (outer bubble column) and taking into account the reactions involved, and the effects of the hydrostatic pressurization on the flow and absorption equilibrium for the ozone and inactive gases in developing the mass balance models. We constructed an algorithm to evaluate the U-tube reactor performance based on the mass balance models. The hydrodynamics and mass transfer characteristics in the inner tube were measured and their correlations were incorporated in the simulation model. Available literature data and correlations on the rates of reactions between ozone and organic substances, the gas-liquid equilibrium for the active and inactive gases and the fluid mixing properties are also incorporated in the simulation model. The simulation results well explained the available data on the ozone absorption efficiency and the removal efficiency of odorous material (2-MIB) in a pilot plant and a real U-tube reactor. It is found that the ozone absorption is practically a single function of the gas/liquid ratio, while the decomposition efficiency of 2-MIB is a single function of the ozone dose for the water quantity to be treated

System configuration, fault detection, location, isolation and restoration: a review on LVDC Microgrid protections

Low voltage direct current (LVDC) distribution has gained the significant interest of research due to the advancements in power conversion technologies. However, the use of converters has given rise to several technical issues regarding their protections and controls of such devices under faulty conditions. Post-fault behaviour of converter-fed LVDC system involves both active converter control and passive circuit transient of similar time scale, which makes the protection for LVDC distribution significantly different and more challenging than low voltage AC. These protection and operational issues have handicapped the practical applications of DC distribution. This paper presents state-of-the-art protection schemes developed for DC Microgrids. With a close look at practical limitations such as the dependency on modelling accuracy, requirement on communications and so forth, a comprehensive evaluation is carried out on those system approaches in terms of system configurations， fault detection, location, isolation and restoration

A low-cost sensing system for quality monitoring of dairy products

The dairy industry is in need of a cost-effective, highly reliable, very accurate, and fast measurement system to monitor the quality of dairy products. This paper describes the design and fabrication works undertaken to develop such a system. The techniques used center around planar electromagnetic sensors operating with radio frequency excitation. Computer-aided computation, being fast, facilitates on-line monitoring of the quality. The sensor technology proposed has the ability to perform volumetric penetrative measurements to measure properties throughout the bulk of the product