Problems Encountered With The Average Potential Method of Analyzing Substation Grounding Systems

1985 ◽  
Vol PAS-104 (12) ◽  
pp. 3585-3596 ◽  
Author(s):  
D. Garrett ◽  
J. Pruitt
Keyword(s):  
Potential Method ◽  
Average Potential

A Practical Algorithm for Calculating the Impulse Earthing Resistances of Vertical Earthing Electrodes

2021 ◽  
Vol 1 (2) ◽  
pp. 15-20
Author(s):  
Yongzheng Zhang ◽  
◽  
Xiaoqing Zhang ◽  
Keyword(s):  
Current Density ◽  
Potential Method ◽  
Effective Radius ◽  
Nonlinear Characteristic ◽  
Ionization Zone ◽  
Average Potential ◽  
Previous Algorithm ◽  
Practical Algorithm ◽  
Soil Ionization ◽  
The Relationship

An algorithm is proposed in this paper for calculating the impulse earthing resistances of vertical earthing electrodes. The proposed algorithm employs the average potential method to derive the formula of the low current earthing resistance. Unlike the previous algorithm, the soil ionization effect under high impulse current is taken into account by introducing a nonlinear characteristic to represent the relationship between the electric field and current density in the ionization zone around the earthing electrode. On the basis of the nonlinear characteristic, the effective radius is evaluated for the equivalent earthing electrode. Then, the impulse earthing resistance can be calculated by substituting the effective radius into the formula of the low current earthing resistance. A comparison is also made between calculated and measured results to confirm the validity of the proposed algorithm. Keywords: Earthing Resistance; Vertical Earthing Electrode; Average Potential Integral; Soil Ionization; Current Density;

Wind Turbine Grounding Resistance Numerical Calculation

2014 ◽  
Vol 1065-1069 ◽  
pp. 3414-3421
Author(s):  
Cong Li ◽  
Ke Jie Huang ◽  
Xiao Qing Zhang ◽  
Nai Wen Hu
Keyword(s):  
Wind Turbine ◽  
Integral Formula ◽  
Potential Method ◽  
Personal Safety ◽  
Grounding Resistance ◽  
Matlab Program ◽  
Test Platform ◽  
Average Potential ◽  
The Empirical Analysis ◽  
Grounding Resistance Measurement

With the increase capacity of wind turbines, grounding device's influence on the equipment and personal safety is becoming more and more significant. In order to calculate the grounding resistance of a wind turbine more accurately, in this paper, based on the Neumann integral formula and the average potential method is applied to derive a formula which can calculate the value of grounding resistance. A general MATLAB program corresponding to the calculation formula is compiled. By comparing the numerical value with the empirical analysis results and building a grounding resistance measurement test platform the correctness of the formulas and program is verified.

Method for calculating the loss asymmetric vibrators with a remote power point

2021 ◽  
Author(s):  
O.V. Popov ◽  
A.V. Tumashov ◽  
G.N. Borisov
Keyword(s):  
Input Resistance ◽  
Potential Method ◽  
Mirror Image ◽  
Heat Losses ◽  
Image Method ◽  
Electric Length ◽  
Average Potential ◽  
The Media ◽  
Power Point ◽  
The Cost

Existing software tools such as Altair FEKO, Ansys HFSS do not allow correct optimization of asymmetrical vibrators, the design of which includes grounding and counterweights. Meanwhile, counterweights often have large dimensions and high cost, comparable to the cost of antenna radiating elements. These circumstances make the development of a method for calculating the input impedance of an asymmetrical vibrator with a partially recessed base urgent. The proposed method for calculating the input resistance was built in the electrostatic approximation, which made it possible to exclude the radiation resistance from the calculation, leaving only heat losses in the underlying surface. The combination of the mirror image method and the average potential method allows one to take into account the influence of the interface between the media. The calculations performed using the developed technique allow making recommendations for determining the grounding depth and the need to install counterweights, depending on the type of soil and the electric length of the vibrator

Modulated structures in (Bi,Pb)-Sr-Ca-Cu-O films

1990 ◽  
Vol 48 (4) ◽  
pp. 62-63
Author(s):  
Shozo Ikeda ◽  
Hirotoshi Hayakawa ◽  
Daniel R. Dietderich
Keyword(s):  
Rf Magnetron Sputtering ◽  
Potential Method ◽  
High Tc ◽  
Bscco System ◽  
Heat Treated ◽  
Modulated Structures ◽  
High Tc Phase ◽  
Deposited Films ◽  
Sputtering System

Pb addition makes easier to form the high Tc phase in the BSCCO system. However, Pb easily vaporized at high temperature. A controlled Pb potential method has been applied to grow the high Tc phase in films. Initially, films are deposited on cleaved MgO substrates using an rf magnetron sputtering system. These amorphous as-deposited films are heat treated in a sealed gold capsule along with a large pellet of Pb-added BSCCO. Details of the process and characterization of the films have been reported elsewhere (1). Films trated for 0.5h at 850° C contain mainly the low Tc phase with a small amount of the high Tc phase. Hawever, films treated for 3h at 850°C consist mainly of the high Tc phase. This film is superconductive with a Tc(zero) of 106K. The Pb/Bi ratio of the films, analysed by SEM- EDS, are 0.12 and 0.18 for heat tratment times of 0.5 and 3h, respectively. The present study investigates the modulated structures of these films using HREM.

Assays for Phospholipid-Dependent Formation of Thrombin and Xa: A Potential Method for Quantifying Lupus Anticoagulant Activity

1991 ◽  
Vol 66 (04) ◽  
pp. 453-458 ◽  
Author(s):  
John T Brandt
Keyword(s):  
Specific Activity ◽  
Anticoagulant Activity ◽  
Factor Xa ◽  
Clinical Importance ◽  
Potential Method ◽  
Quantitative Expression ◽  
Increased Risk ◽  
Apparent Association

SummaryLupus anticoagulants (LAs) are antibodies which interfere with phospholipid-dependent procoagulant reactions. Their clinical importance is due to their apparent association with an increased risk of thrombo-embolic disease. To date there have been few assays for quantifying the specific activity of these antibodies in vitro and this has hampered attempts to purify and characterize these antibodies. Methods for determining phospholipid-dependent generation of thrombin and factor Xa are described. Isolated IgG fractions from 7 of 9 patients with LAs were found to reproducibly inhibit enzyme generation in these assay systems, permitting quantitative expression of inhibitor activity. Different patterns of inhibitory activity, based on the relative inhibition of thrombin and factor Xa generation, were found, further substantiating the known heterogeneity of these antibodies. These systems may prove helpful in further purification and characterization of LAs.

Use of cold tolerant eucalyptus species as a partial replacement for southern mixed hardwoods

TAPPI Journal ◽  
2012 ◽  
Vol 11 (7) ◽  
pp. 29-35 ◽  
Author(s):  
PETER W. HART ◽  
DALE E. NUTTER
Keyword(s):  
Potential Method ◽  
The United States ◽  
Partial Replacement ◽  
Growth Time ◽  
Eucalyptus Species ◽  
Cold Tolerant ◽  
Hardwood Pulp ◽  
Time Required ◽  
The Cost ◽  
Operational Data

During the last several years, the increasing cost and decreasing availability of mixed southern hardwoods have resulted in financial and production difficulties for southern U.S. mills that use a significant percentage of hardwood kraft pulp. Traditionally, in the United States, hardwoods are not plantation grown because of the growth time required to produce a quality tree suitable for pulping. One potential method of mitigating the cost and supply issues associated with the use of native hardwoods is to grow eucalyptus in plantations for the sole purpose of producing hardwood pulp. However, most of the eucalyptus species used in pulping elsewhere in the world are not capable of surviving in the southern U.S. climate. This study examines the potential of seven different cold-tolerant eucalyptus species to be used as replacements for, or supplements to, mixed southern hardwoods. The laboratory pulping and bleaching aspects of these seven species are discussed, along with pertinent mill operational data. Selected mill trial data also are reviewed.

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