Modeling of Inverter-Based Resources Using Equivalent Current Sources in EMTP-RV

2020 ◽  
Author(s):  
Soham Roy ◽  
Fernando Osorio ◽  
Surya Santoso ◽  
Robert F. Arritt
Keyword(s):  
Equivalent Current

scholarly journals Clinical Validation of the Champagne Algorithm for Evoked Response Source Localization in Magnetoencephalography

2021 ◽  
Author(s):  
Abhishek S. Bhutada ◽  
Chang Cai ◽  
Danielle Mizuiri ◽  
Anne Findlay ◽  
Jessie Chen ◽  
...  
Keyword(s):  
Evoked Potentials ◽  
Source Localization ◽  
Clinical Population ◽  
Evoked Responses ◽  
Localization Algorithm ◽  
Equivalent Current Dipole ◽  
Current Dipole ◽  
Tumor Patients ◽  
Equivalent Current ◽  
Sensory Evoked

AbstractMagnetoencephalography (MEG) is a robust method for non-invasive functional brain mapping of sensory cortices due to its exceptional spatial and temporal resolution. The clinical standard for MEG source localization of functional landmarks from sensory evoked responses is the equivalent current dipole (ECD) localization algorithm, known to be sensitive to initialization, noise, and manual choice of the number of dipoles. Recently many automated and robust algorithms have been developed, including the Champagne algorithm, an empirical Bayesian algorithm, with powerful abilities for MEG source reconstruction and time course estimation (Wipf et al. 2010; Owen et al. 2012). Here, we evaluate automated Champagne performance in a clinical population of tumor patients where there was minimal failure in localizing sensory evoked responses using the clinical standard, ECD localization algorithm. MEG data of auditory evoked potentials and somatosensory evoked potentials from 21 brain tumor patients were analyzed using Champagne, and these results were compared with equivalent current dipole (ECD) fit. Across both somatosensory and auditory evoked field localization, we found there was a strong agreement between Champagne and ECD localizations in all cases. Given resolution of 8mm voxel size, peak source localizations from Champagne were below 10mm of ECD peak source localization. The Champagne algorithm provides a robust and automated alternative to manual ECD fits for clinical localization of sensory evoked potentials and can contribute to improved clinical MEG data processing workflows.

Simple inversion of time‐domain electromagnetic data

Geophysics ◽  
1984 ◽  
Vol 49 (7) ◽  
pp. 925-933 ◽  
Author(s):  
C. T. Barnett
Keyword(s):  
Time Domain ◽  
Eddy Currents ◽  
Early Time ◽  
Late Time ◽  
Current Filament ◽  
Equivalent Current ◽  
Time Domain Electromagnetic ◽  
Inversion Procedure ◽  
Current Filaments ◽  
Simple Inversion

The eddy currents induced in a thin confined conductor by a fixed‐loop time‐domain EM system can be represented by a single equivalent current filament. The equivalent current filament stays in the plane of the conductor at all times during the decay of the secondary field, but tends to migrate from a position of maximum primary field coupling at early time toward the center of the conductor at late time. This filament approximation is used in the design of a least‐squares inversion procedure which fits circular or rectangular current filaments to an observed eddy current distribution. The inversion procedure provides a rapid but precise means of estimating the position, size, and attitude of a conductor which has been detected by a time‐domain EM survey.

scholarly journals A model for estimating the relation between the Hall to Pedersen conductance ratio and ground magnetic data derived from CHAMP satellite statistics

2007 ◽  
Vol 25 (3) ◽  
pp. 721-736 ◽  
Author(s):  
L. Juusola ◽  
O. Amm ◽  
K. Kauristie ◽  
A. Viljanen
Keyword(s):  
Current Density ◽  
Geomagnetic Latitude ◽  
Magnetic Data ◽  
Equivalent Current ◽  
Champ Satellite ◽  
Long Time ◽  
Conductance Ratio ◽  
Ground Magnetic ◽  
Eiscat Radar ◽  
Magnetic Satellite

Abstract. The goal of this study is to find a way to statistically estimate the Hall to Pedersen conductance ratio α from ground magnetic data. We use vector magnetic data from the CHAMP satellite to derive this relation. α is attained from magnetic satellite data using the 1-D Spherical Elementary Current Systems (SECS). The ionospheric equivalent current density can either be computed from ground or satellite magnetic data. Under the required 1-D assumption, these two approaches are shown to be equal, which leads to the advantage that the statistics are not restricted to areas covered by ground data. Unlike other methods, using magnetic satellite measurements to determine α ensures reliable data over long time sequences. The statistical study, comprising over 6000 passes between 55° and 76.5° northern geomagnetic latitude during 2001 and 2002, is carried out employing data from the CHAMP satellite. The data are binned according to activity and season. In agreement with earlier studies, values between 1 and 3 are typically found for α. Good compatibility is found, when α attained from CHAMP data is compared with EISCAT radar measurements. The results make it possible to estimate α from the east-west equivalent current density Jφ; [A/km]: α=2.07/(36.54/|Jφ|+1) for Jφ<0 (westward) and α=1.73/(14.79/|Jφ+1) for Jφ0 (eastward). Using the same data, statistics of ionospheric and field-aligned current densities as a function of geomagnetic latitude and MLT are included. These are binned with respect to activity, season and IMF BZ and BY. For the first time, all three current density components are simultaneously studied this way on a comparable spatial scale. With increasing activity, the enhancement and the equatorward expansion of the electrojets and the R1 and R2 currents is observed, and in the nightside, possible indications of a Cowling channel appear. During southward IMF BZ, the electrojets and the R1 and R2 currents are stronger and clearer than during northward BZ. IMF BY affects the orientation of the pattern.

scholarly journals Activation of ENaC in collecting duct cells by prorenin and its receptor PRR: involvement of Nox4-derived hydrogen peroxide

2016 ◽  
Vol 310 (11) ◽  
pp. F1243-F1250 ◽  
Author(s):  
Xiaohan Lu ◽  
Fei Wang ◽  
Mi Liu ◽  
Kevin T. Yang ◽  
Adam Nau ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Hydrogen Peroxide ◽  
Spin Trap ◽  
Collecting Duct ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Equivalent Current ◽  
Duct Cells ◽  
Collecting Duct Cells ◽  
Nanomolar Range

The collecting duct (CD) has been recognized as an important source of prorenin/renin, and it also expresses (pro)renin receptor (PRR). The goal of this study was to examine the hypothesis that prorenin or renin via PRR regulates epithelial Na+ channel (ENaC) activity in mpkCCD cells. Transepithelial Na+ transport was measured by using a conventional epithelial volt-ohmmeter and was expressed as the calculated equivalent current ( Ieq). Amiloride-inhibitable Ieq was used as a reflection of ENaC activity. Administration of prorenin in the nanomolar range induced a significant increase in Ieq that was detectable as early as 1 min, peaked at 5 min, and gradually returned to baseline within 15 min. These changes in Ieq were completely prevented by a newly developed PRR decoy inhibitor, PRO20. Prorenin-induced Ieq was inhibitable by amiloride. Compared with prorenin, renin was less effective in stimulating Ieq. Prorenin-induced Ieq was attenuated by apocynin but enhanced by tempol, the latter effect being prevented by catalase. In response to prorenin treatment, the levels of total reactive oxygen species and H2O2 were both increased, as detected by spin-trap analysis and reactive oxygen species (ROS)-Glo H2O2 assay, respectively. Both siRNA-mediated Nox4 knockdown and the dual Nox1/4 inhibitor GKT137892 attenuated prorenin-induced Ieq. Overall, our results demonstrate that activation of PRR by prorenin stimulates ENaC activity in CD cells via Nox4-derived H2O2.

scholarly journals RECONSTRUCTION OF OBJECTS BURIED IN LAYERED MEDIA BASED ON AN EQUIVALENT CURRENT SOURCE

2015 ◽  
Vol 44 ◽  
pp. 171-182 ◽  
Author(s):  
Peng Zhang ◽  
Peng Fei ◽  
Xin Wen ◽  
Feng Nian
Keyword(s):  
Current Source ◽  
Layered Media ◽  
Equivalent Current

Mixed Measurement State Estimation of the Equivalent Current Transformation Based on Generalized Tellegen's Theorem

2013 ◽  
Vol 373-375 ◽  
pp. 970-975
Author(s):  
Gui Hua Lin ◽  
Tao Wang ◽  
Yu Ying Wang ◽  
Li Guo Zheng
Keyword(s):  
State Estimation ◽  
Numerical Stability ◽  
Stability Problem ◽  
Jacobian Matrix ◽  
Estimation Method ◽  
Constant Matrix ◽  
Equivalent Current ◽  
Scada System ◽  
Current State ◽  
Secondary Factor

One of the most important ways to enhance the speed of state estimation is to establish the constant matrix Jacobian. This essay puts forward the state estimation method of the equivalent current transformation based on the Generalized Tellegens Theorem. This estimation method establishes the constant Jacobian matrix without neglecting the secondary factor making use of the Generalized Tellegens Theorem, solves the numerical stability problem caused by the establishment of the constant Jacobian matrix in the current state estimation, and has the advantages of a relatively rapid computing rate, making advantage of measuremnt of WAMS and SCADA system, and an unparalleled astringency. The method put forward in this essay has been verified through IEEE-30 Node System, and the efficiency of it has been fully proved by the example results.

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