Analysis of grounding systems in soils with finite volumes of different resistivities.
J. Ma and F. P. Dawalibi.
Abstract: A theoretical model for the analysis of grounding systems located in soils with finite volumes of arbitrary resistivities is presented. The boundary element method is used for the analysis. The procedures in the analysis are described in detail and the essential equations are presented. Analytical and numerical validations are also carried out in the process. The results obtained using the new approach are in agreement with well-known simple case results and converge asymptotically to the uniform soil case. There is a wide range of practical grounding system scenarios which can be accurately modeled by using this new soil type. Examples showing several finite volume soil models are also presented.

Extended analysis of ground impedance measurement using the fall-of-potential method.
J. Ma and F. P. Dawalibi.
Abstract: An extended analysis of ground impedance measurement using the Fall-of-Potential method is presented. An interesting curve representing the exact locations of the potential probe when the potential and current probes are in different directions is obtained for the first time. Curves representing measurement error are also presented for the case when the potential probe is placed in locations where the correct ground impedance cannot be measured. A similar analysis for ground impedance measurements in multilayer soils is also discussed. The study presented in this paper has extended the theory of the conventional Fall-of-Potential method and the results obtained can serve as a practical guide for ground impedance measurements made using this method.

Determination of rail conductor characteristics for electromagnetic interference studies.
J. Liu, F.P. Dawalibi, Y. Yang, J. Ma, and R.D. Southey.
Abstract: This paper describes the approach used to establish a dynamic rail conductor characteristics database for the accurate simulation of complex realistic right-of-way electromagnetic interference problems. The equivalent model of the rail, interpolation methods and the rail conductor database are presented in detail. A typical example involving electromagnetic interference between high voltage power transmission lines and a railway is used to illustrate the use of the dynamic rail conductor database.

HVDC advanced analysis methods for grounding design and dc interference mitigation techniques.
J. Liu, F.P. Dawalibi, J. Ma, and R.D. Southey.
Abstract: This paper presents recent advances made in HVDC grounding design techniques and the DC interference effects generated by HVDC ground electrodes on neighboring metallic utilities, with a particular emphasis on buried pipelines (oil, gas, water). The influence of soil structure on the performance of ground electrodes and on interference levels is demonstrated. A realistic case is modeled in detail to illustrate the accuracy, flexibility, and capabilities of these methods.

Application of the electromagnetic field method to study a communication satellite site damaged by lightning.
W. Ruan, R.D. Southey, F.P. Dawalibi, and N.A. Idris.
Abstract: This paper presents a case study of a satellite communications site at which equipment was damaged during a lightning storm. The transient ground potential rise (GPR) and stress voltages on the damaged equipment (HPA) during a lightning storm are obtained using the electromagnetic field theory method. The stress voltage on the HPA is reduced by 75% (from 25 kV to 6 kV) when the isolated signal ground wire is electrically bonded to a nearby equipment ground. An extended grounding system has little influence on the stress voltages at the beginning of the transient period; however, it reduces the stress voltages significantly (by about 50%) after the first 3 ms.

Capacitive discharge of metallic structures close to high voltage power lines.
J. Ma and F.P. Dawalibi.
Abstract: A study of capacitive discharge of metallic structures that are close to high voltage power lines has been carried out. An equivalent circuit for modeling the transient capacitive discharge phenomenon is presented and analytical expressions for this transient behavior have been derived. Numerical results have been obtained and compared with published results for initial value of the transient potential and potential peaks after the steady-state conditions have been established. The agreement is excellent. The equivalent circuit model and analytical expressions for the transient behavior of the capacitive discharge process presented in this paper can be easily applied to many practical situations.

Latest analytical and computational techniques in grounding. (In Chinese)
J. Ma and F.P. Dawalibi.
Abstract: The main purpose of this paper is to point out the common misconceptions in grounding analysis and design and to introduce the latest computational techniques in grounding. Software packages used in grounding analysis and design are also described.

Latest analytical and computational techniques in electromagnetic interference. (In Chinese)
J. Ma and F.P. Dawalibi.
Abstract: Using practical engineering examples to demonstrate the latest computational techniques in the areas of electromagnetic interference, electromagnetic compatibility, and lightning. Descriptions of the software packages used in these areas are also included.

For a complete list of publications by SES please refer to our web site.

Electromagnetic field produced by overhead power lines
S. Nikolovski and J. Ma.

Effect of soil structures on grounding systems consisting of steel conductors
G. Yu, J. Ma, and F.P. Dawalibi.

The effects of low resistivity cylindrically shaped soil volumes on grounding systems.
Y. Yang, J. Ma, F.P. Dawalibi.

Integrated analysis software for electromagnetic interference between power lines and neighboring utilities.
Y. Li, F.P. Dawalibi, and J. Ma.

Optimum and economical deployment method of surge arresters on distribution lines for insulation failure due to lightning - a circuit model analysis.
W. Ruan, J. Ma, S. Fortin, and F.P. Dawalibi, and E.J. Middleton.

Reduction of current unbalance in multi-circuit heavily loaded transmission lines
J. Ma, S. Fortin, R.D. Southey, F.P. Dawalibi, and W Ruan.

Optimum and economical deployment method of surge arresters on distribution lines for insulation failure due to lightning - an electromagnetic field computation analysis.
W. Ruan, J. Ma, S. Fortin, F.P. Dawalibi, and E.J. Middleton.

Computation of cable parameters for pipe-type cables with arbitrary pipe thicknesses.
Y. Yang, J. Ma, and F.P. Dawalibi.

Computation of power line structure surge impedances using the electromagnetic field method.
F.P. Dawalibi, W. Ruan, S. Fortin, J. Ma, and W.K. Daily.