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Vol. 18 (2015 year), No. 1
Kuklin D. V., Selivanov V. N.
Software for calculations of surge processes
in ground conductors and grounded objects
Software for calculations related to propagation of electromagnetic waves in high-voltage objects (transmission towers and their grounding, substation grounding) has been described in the paper. Using the software the oblique thin wire simulation method proposed by Guiffaut et al. (2012) has been verified for conductive medium
(in Russian, стр.6, fig. 5, tables. 1, ref 7, Adobe PDF, Adobe PDF 0 Kb)
Vol. 19 (2016 year), No. 4, DOI: 10.21443/1560-9278-2016-4
Kuklin D. V. , Efimov B. V.
Influence of location of the lead wires on calculation results of grounding transient characteristics of a grounding rod
For calculations and measurements of transient characteristics of groundings, the current and potential lead wires are frequently used accordingly to inject the current into the grounding and find the grounding potential rise (GPR). The results of the calculations and measurements can be dependent on the location of the current and potential lead wires due to mutual influence between them and the grounding wire. It is important to determine to what extent the location of the wires influences the calculation results for the grounding with a simple configuration. Notably, in contrast to the measurements, for the calculations it is possible to locate wires vertically, also the potential lead wire can be replaced by the integral of the electric field. For the calculations the finite difference time domain method (FDTD) has been used in the work. In order to estimate to what extent the calculated GPR can be influenced by location of the wires, calculations with different wires locations have been carried out. An analysis of the calculation results has been made. There are calculation methods in which the injection of the current and calculation of the GPR are performed without the current and potential lead wires. The method based on the telegrapher's equations is one of such methods. In order to determine what location of the lead wires gives the same calculation results as those of the method that uses the telegrapher's equations, a comparison of calculation results of two methods has been made. Based on the calculation results it can be concluded that the calculated transient characteristics depend to a different extent on such factors as mutual location of the lead wires and the grounding wire, replacing the potential lead wire by the integral of the electric field, electrical parameters of the soil. Location of one of the lead wires above the grounding wire significantly reduces the calculated GPR. Calculation results for a perpendicular location of three wires (the lead ones and the grounding wire) using the FDTD method correspond to those of the method based on the telegrapher's equation
(in Russian, стр.8, fig. 8, tables. 0, ref 7, Adobe PDF, Adobe PDF 0 Kb)
Vol. 21 (2018 year), No. 4, DOI: 10.21443/1560-9278-2018-21-4
The finite difference time domain method contains additional techniques for modeling thin wires whose diameter is substantially smaller than the cell size. Among them, there is a group of techniques where thin wires are modeled by correcting the medium surrounding the wire. Although in this case only the wires located along the electric field nodes can be modeled, techniques of this group do not cause calculation errors if the wires are located in the absorbing boundary conditions necessary to model thin wires with infinite length. Several techniques have been compared for the case when two wires are separated by one-cell gap. Influence of magnetic field modification around the gap between wires on calculation results has been examined. By calculations with the dipole antenna, it has been shown that correction of the magnetic field around the gap does not increase calculation accuracy (at least for the considered cases). However, this correction eliminates numerical instability. In this paper, it has been proposed to apply a magnetic field correction at the ends of the conductor only in cases where the conductors are separated by one cell, but not at each end of the conductors, as previously suggested.
(in Russian, стр.8, fig. 10, tables. 0, ref 8, adobePDF, adobePDF 0 Kb)