Qualitative Model of the Input Impedance of Rectangular Microstrip Antenna

Int J Numerical Modelling

Sadeghi

2020

In this paper, an efficient hybrid method is proposed for transient analysis of an overhead line equipped with a grounded arrester. The proposed method adopts a nonlinear equivalent circuit consisting of linear and nonlinear parts respectively associated with the overhead line and the arrester. In the first part of the paper, an intelligent model based on qualitative concepts in electromagnetics is proposed for derivation of the linear part. With the use of this qualitative model, the behavior of the linear part is first extracted as simple and unchanged membership functions, and effects of parameters of the problem, that is, the height of the overhead line and the electrical parameters of the ground, are then extracted as simple curves so that the linear part based on the qualitative model is efficiently computed in the frequency domain. The qualitative model, in contrast with the conventional numerical methods, is very efficient, and in comparison with the approximate ones, is broad band. In the second part of the paper, with the aid of an efficient optimization algorithm, called intelligent water drop algorithm (IWD), the lightning overvoltage across the arrester is efficiently computed.

Section: Norton Equivalent Circuitmentioning

confidence: 87%

Section: Introductionmentioning

confidence: 99%

An efficient spectral balance method for transient analysis of single phase overhead lines in the presence of surge arresters

Taghavi

Int J Numerical Modelling

Sadeghi

2020

“…For poorly resistive soils and fast-fronted currents, however, the ionization effect is dominant so that the dispersion effect can be disregarded. The next step is to extract closed-form soluitions for effective length of counterpoise wires buried in both-affected soil using combining the proposed method with optimization algorithms [27][28][29][30][31], or fuzzy inference techniques [32][33][34][35][36][37][38][39] that is in progress.…”

Section: Discussionmentioning

confidence: 99%

Validity of Improved MTL for Effective Length of Counterpoise Wires under Low and High-Valued Lightning Currents

2020

AEM

In this paper, an efficient modeling approach called improved MTL is used to predict effective length of counterpoise wires considering both ionization and dispersion of soils. This paper consists of two parts. At first part, validity of the model for computing effective length of counterpoise wires considering only soil ionization is investigated. The simulation results show that the improved MTL-based effective length of counterpoise wire are in good agreement with the existing formulae. Application of this modeling approach to include ionization and dispersion effects simultaneously (both-affected soil) is carried out in the second part. The simulation results show that in both-affected soils, the effective length with respect to only-ionized soils, is decreased especially in highly resistive soils under slow-fronted currents. This makes inclusion of both effects financially important in designing counterpoise wires.

“…Otherwise, the simultaneous effects should be considered in analyzing grounding electrodes. Extracting formulae for effective length of grounding electrodes in both-affected soils using optimization algorithm (Yazdi et al, 2015;Taheri and Ostadzadeh, 2014;Teimoory et al, 2016;Samiian et al, 2016;Bahrami and Ostadzadeh, 2019) and fuzzy techniques (Ostadzadeh, 2015;Ostadzadeh et al, 2017;Ostadzadeh, 2013Ostadzadeh, , 2014Ostadzadeh et al, 2008Ostadzadeh et al, , 2009 is another study that is in progress.…”

Section: Neither Effects Only Dispersion Only Ionization Both Effectsmentioning

confidence: 99%

Parametric dependence of lightning impulse behavior of grounding electrodes buried in a dispersive and ionized lossy soil under first- and subsequent-stroke currents

Sajadi

Sadeghi

2020

COMPEL

Self Cite

Purpose The purpose of this paper is to investigate the simultaneous effects of ionization and dispersion of soil on the impulse behavior of grounding electrodes under first and subsequent stroke currents. Design/methodology/approach A recently introduced technique called improved multi-conductor transmission line (MTL) is simplified for grounding electrodes buried in both-affected soils. Findings The simulation results show that including the two effects simultaneously in highly resistive soils under high-valued subsequent stroke current is recommended. Otherwise, simultaneous effects can be disregard. Originality/value To the best of the authors’ knowledge, there is no research on sensitivity analyses for the simultaneous inclusion of the two effects on the effective length and the induced voltage on the soil surface. To this end, the simplified MTL is applied to the grounding electrodes. The simulation results show that the computational efficiency in comparison with previous methods is, first, considerably increased. Second, the simultaneous effects result in decreasing the soil surface voltage with respect to situations where either ionization or dispersion is taken into account (single-affected soils). In other words, the performance of grounding systems is improved. Third, the effective length in both-affected soil is has a middle value with respect to the single-affected soil. Such findings practically and financially are of importance.