Polarity Asymmetry in Lightning Return Stroke Speed Caused by the Momentum Associated with Radiation

In positive lightning return strokes, the net momentum transported by the radiation field has the same direction as the momentum associated with electrons, whereas the momentum associated with electrons is in opposite direction to the momentum of radiation in negative return strokes. It is shown here that this polarity asymmetry could limit the maximum speed of positive return strokes with respect to the negative return strokes.

Electromagnetic model for the study of transitory phenomena associated with atmospheric discharges on transmission lines

The analysis of a research work developed in the company C.V.G CARBONORCA of Venezuela is presented, which has two gas purification plants for the cooking area, designed to purify the gas that comes from the cooking ovens. Each plant is made up of solenoid valves, pneumatic valves, transmitters, process mimic panel and a supervisory system. All these elements are governed by a SIEMENS S5-115U PLC which is in a state of obsolescence, which is why the replacement of these automata by ALLEN BRADLEY ContolLogix automata was designed, in order to guarantee continuity in operations in plant. The research was done with a descriptive design of the field experimental type. A code for each gas treatment plant was obtained in RSLOGIX 5000 v17.00.00 and the update of the database of the supervisory system. The operation of the program was also verified through a simulation of the plant in a supervisory system, the deployment of which was designed for this purpose. Keywords: Automation, Modernization, ControlLogix, Supervisory System, Mimic Panel References [1]M. Uman, D. Mclain and P. Krider. “The Electromagnetic Radiation from a finite antenna” AJP, vol. 43, 1975. 1975. [2]A. Agrawal, H. Price and S. Gurbaxani. “Transient response of multiconductor transmission lines excited by a no uniform electromagnetic field”. IEEE Transactions on electromagnetic compatibility, (2), 119-129. 1980. [3]C. Nucci, F. Rachidi, M. Ianoz and C. Mazzetti. “Comparison of two coupling models for lightning-induced overvoltage calculations”. IEEE Transactions on power delivery, 10(1), 330-339. 1995. [4]R. Thottappillil and M. Uman. “Comparison of lightning return‐stroke models”. Journal of Geophysical Research: Atmospheres, 98(D12), 22903-22914. 1993. [5]K. Yee. “Numerical solution of initial boundary value problems involving Maxwell’s equations in isotropic media”, IEEE Transactions on Antennas and Propagation, vol. AP-14, no. 3, pp. 302–307, May 1966. 1966. [6]A. Taflove and S. Hagness. “Computational Electrodynamics: The Finite-Difference Time-Domain Method”. Boston-London: 2005. [7]A. Elsherbeni and V. Demir. “The finite-difference time-domain method for electromagnetics with MATLAB simulations”. The Institution of Engineering and Technology. 2016. [8]V. Silva. “Aplicação do método FDTD para avaliação da resposta de linhas de transmissão e aterramentos elétricos frente a descargas atmosféricas”. Dissertação de Mestrado, Universidade federal de minas gerais. Belo Horizonte, Brasil. 2017. [9]T. Noda and S. Yokoyama. “Thin wire representation in finite difference time domain surge simulation”. IEEE Transactions on Power Delivery, 17(3), 840-847. 2002. [10]R. Chamié-Filho. Análise de tensões induzidas em linhas de distribuição de baixa tensão frente a uma descarga atmosférica. 2009. [11]R. Jiménez. “Lightning Induced Voltages on Overhead Lines above Non-Uniform and Non-Homogeneous Ground” Doctoral dissertation, Universidad Nacional de Colombia-Sede Medellín. 2014. [12]S. Visacro and A. Soares. “HEM: A model for simulation of lightning-related engineering problems”. IEEE Transactions on power delivery, 20(2), 1206-1208. 2005. [13]J. Herrera. “Nuevas aproximaciones en el cálculo de tensiones inducidas por descargas eléctricas atmosféricas”. Programa de Doctorado en Ingeniería Eléctrica, Facultad de Ingeniería, Departamento de Ingeniería Eléctrica y Electrónica, Universidad Nacional de Colombia, Bogotá, 128 . 2006. [14]C. McAfee. “Lightning return stroke electromagnetics-time domain evaluation and application” Doctoral dissertation. 2016. [15] S. Gedney. “Introduction to the finite-difference time-domain (FDTD) method for electromagnetics”. Synthesis Lectures on Computational Electromagnetics, 6(1), 1-250. 2011. [16]Y. Taniguchi, Y. Baba, N. Nagaoka and A. Ametani. “An improved thin wire representation for FDTD computations”. IEEE Transactions on Antennas and Propagation, 56(10), 3248-3252. 2008. [17]E. Soto. “Cálculo de campo electromagnético producido por rayo para terreno no plano y su efecto en las tensiones inducidas en líneas de distribución”. Tesis de Maestría, Universidad Nacional de Colombia. Manizales, Colombia. 2010. [18]D. Sullivan. “Electromagnetic simulation using the FDTD method”. John Wiley & Sons. 2013.

An analysis of manual and autoanalysis for submicrosecond parameters in the typical first lightning return stroke

The mechanism on how lightning detection system (LDS) operated never been exposed by manufacturer since it was confidential. This scenario motivated the authors to explore the issue above by using MATLAB to develop autoanalysis software based on the feature extraction. This extraction is intended for recognizing the parameters in the first return stroke, and compare the measurement between the autoanalysis software and the manual analysis. This paper is a modification based on a previous work regarding autoanalysis of zero-crossing time and initial peak of return stroke using features extraction programming technique. Further, the parameter on rising time of initial peak is added in this autoanalysis programming technique. Finally, the manual analysis using WaveStudio (LeCroy product) of those two lightning parameters is compared with autoanalysis software. This study found that the autoanalysis produce similar result with the manual analysis, hence proved the reliability of this software.

Bidirectional Active Piezoelectric Actuator Based on Optimized Bridge-Type Amplifier

Piezoelectric actuators based on bridge displacement amplifying mechanisms are widely used in precision driving and positioning fields. The classical bridge mechanism relies on structural flexibility to realize the return stroke, which leads to the low positioning accuracy of the actuator. In this paper, a series bridge mechanism is proposed to realize a bidirectional active drive; the return stroke is driven by a piezoelectric stack rather than by the flexibility of the structure. By analyzing the parameter sensitivity of the bridge mechanism, the series actuation of the bridge mechanism is optimized and the static and dynamic solutions are carried out by using the finite element method. Compared with the hysteresis loop of the piezoelectric stack, the displacement curve of the proposed actuator is symmetric, and the maximum nonlinear error is improved. The experimental results show that the maximum driving stroke of the actuator is 129.41 μm, and the maximum nonlinear error is 5.48%.