Majlesi Journal of Telecommunication Devices Vol. 6, No. 4, December 2017 99 Simulation and Analysis of Electromagnetic Fields Resulting From Lightning in the Proximity of Watercraft using Maxwell v.15 Software Shahrouz Nasiri, Mehdi Tabasi, Alireza Bakhshinejhad Department of electrical engineering, Sowmesara branch, Islamic Azad University, Sowmesara, Iran. Email: mehdi.tabasi@gmail.com Received: November 2017 Revised: November 2017 Accepted: November 2017 ABSTRACT: Strike of lightnings with sea, due to the high conductivity of salty water creates more extreme electromagnetic fields in comparison with lightnings in land. This paper deals with analysis and simulation of electromagnetic fields resulting from lightning in the proximity of a watercraft in sea and its effect on the equipment on the watercraft. The magnitude of electric and magnetic fields is first calculated using Uman integral equations to calculate the electric field resulting from a limited current channel on a perfect conductor. To solve the field integrals, dual precision exponential model was used for the lightning’s current. Due to limitations of the solution of field integrals, parametric analysis is difficult. For this reason, the lightning channel and watercraft model was simulated in Maxwell software and the obtained fields were compared with the results of integral solution. Considering the closeness of integral and simulation results, with alteration of the peak lightning current and its distance off the watercraft, the field sensitivity to these variables was measured and the results of parametric analysis have been presented for different parts of the watercraft. KEYWORDS: electromagnetic field, lightning, watercraft, sea, Maxwell. 1. INTRODUCTION Sea is the region where lightning easy to be form. The big ship cruising and watercraft on the open sea could be the target to which lightning attacked mostly because of its high mast and outstanding antennas [1]. The lightning disservice effect to watercraft includes the direct effect and indirect effect. Direct effect is the physical effect produced by the lightning strike, which represent as burning, eroding, explosion, structure distortion, high voltage shock wave, magnetic field produced by big current, and the fatal contact voltage and step voltage formed while the lightning current go down along the lightning conductor to the ground or the sea. The indirect effect is the electromagnetic radiation effect, in which the electromagnetic pulse radiation going with the lightning strike disserves the electrical and electronic equipments and system. An electric field has vertical and horizontal elements while its magnetic field has a horizontal element. The fields developed by a lightning are similar to the field resulting from a limited length channel current. If the lightning strike plane is a perfect conductor, the current channel is completely mirrored beneath the plane, and its effect is equivalent to the effect of lightning channel with a length twice as long as the initial length. In [2], integral equations have been presented for obtaining such as field. If the lightning strike plane is a limited conductor, the field equations change horizontally. The magnetic field equation resulting from strike of lightnings with a limited conductor plane in [3] is the frequency zone and electric field resulting from it has been calculated in [4] by Cooray-Rubinstein Formula. Calculations of the electromagnetic field indicate that the field domain resulting from lightning can decrease by up to 50% in a plane with conductivity far weaker than a perfect conductor [5]. As solution of the field integrals as unknown is difficult, typically fields are calculated within certain intervals off the lightning strike site. The fields resulting from strike of lightning in sea at specific intervals in [6], [7] have been calculated with different models. However, the obtained responses are far from each other. One of the reasons of this difference is preliminary modeling for the lightning current. For modeling the lightning current, various models can be used. To prevent complexity of solution of integrals models, many studies have employed a simple triangular signal for simulation of the lightning current [8]. One of the most accurate field modeling is usage of dual exponential model, whose parameters have been calculated in [9] for different lightning pulses with head slope and drop in different waves. However, this model