Parameter Estimation of Vertical Two-Layer Soil Model via Brain Storm Optimization Algorithm
A practical soil model is derived mathematically based on the measurement principles of Wenner’s method. The Wenner’s method is a conventional approach to measuring the apparent soil resistivity. This soil model constitutes two-soil layer with different p
- PDF / 453,328 Bytes
- 12 Pages / 439.37 x 666.142 pts Page_size
- 5 Downloads / 186 Views
stract. A practical soil model is derived mathematically based on the measurement principles of Wenner’s method. The Wenner’s method is a conventional approach to measuring the apparent soil resistivity. This soil model constitutes two-soil layer with different properties vertically. Thus this model is called the vertical two-layer soil model. The motivation for the mathematical model is to estimate relevant parameters accurately from the data obtained from site measurements. This parameter estimation is in fact a challenging optimization problem. From the plotted graphs, this problem features a continuous but non-smooth landscape with a steep alley. This poses a great challenge to any optimization tool. Two prominent algorithms are applied, namely Gauss-Newton (GN) and Brain Storm Optimization (BSO). Results obtained conclude that the GN is fast but diverges due to bad starting points. On the contrary, the BSO is slow but it never diverges and is more stable. Keywords: Brain storm optimization estimation · Soil model
1
·
Grounding
·
Parameter
Introduction
When referring to the power supply and transmission equipment, it is crucially important to investigate the soil resistivity and grounding system resistance [1]. This is due to the reason that an excellent grounding system can guarantee safety to surroundings. This grounding system not only protects substations but also prevents dangers such as extreme ground potential and other ground faults [2]. Most previous works contributed in studying grounding characteristics [3], soil parameter estimation [4,5], safety design [6], and ground potential rise (GPR) [7] or grounding systems in two- and multi-layer soil. The real soil shows a resistivity change in vertical and horizontal directions and practical modeling of grounding systems based on proposed soil models lead to inevitable errors due to improper models. A vertical-layer soil model was used previously to analyze the current distribution, leakage current density, grounding impedance, and surface potential [8]. Numerical methods for measuring the grounding resistance was carried out in [9]. Simple and accurate equations had been deduced for grounding grid resistance in vertical two-layer soil [10]. c Springer International Publishing Switzerland 2016 Y. Tan et al. (Eds.): ICSI 2016, Part I, LNCS 9712, pp. 500–511, 2016. DOI: 10.1007/978-3-319-41000-5 50
Parameter Estimation of Vertical Two-Layer Soil Model via Brain Storm
501
In terms of parameter estimation, the Gauss-Newton method [11] is one of the widely used conventional methods to estimate soil parameters due to its simplicity, effectiveness, and ease for programming. Further, work in [5] discussed and implemented variants of improved Gauss-Newton methods. In this work, we use the image method to build an accurate and equivalent model for vertical twolayer soil. Based on this model, an equation is proposed to study the apparent resistivity expression via Wenner’s method. Having had a solid mathematical model, two algorithms are applied to estimate
Data Loading...
