Assessment of electric potential generated during lightning strike by finite element method

The main effect of lightning is the induced surge voltage within power networks. The paper deals with the assessment of electric potential generated during lightning. A time domain simulation using Finite Element Method was done, considering that the lightning current flows within a discharge channel with variable lengths (15–91 m) and impedances, having various peaks (2.5–40 kA). Both 8/20 μs and 5/320 μs lightning current wave shapes have been considered. The surge voltage waveforms were determined for each lightning current. The assessment of electric potential generated during lightning through phase wire, in soil and near underground power cable was done

ESD Knitted Fabrics from Conductive Yarns Used as Protective Garment for Electronic Industry

Nowadays, interest in protection against electrostatic discharge (ESD), regarded as an important issue, is still growing. ESD may lead to serious economic losses and can also be hazardous to humans. In zones where substances with low values of ignition energy occur, ESD may involve a high risk of fire or explosion. Protective clothing is used to reduce the risk of electrostatic discharge (ESD) in electronics industry as well as in explosive atmospheres. In the manufacturing process of electronic products, significant percentage-related failures due to ESD phenomena that occur on the production line, especially where they are not installed systems and rigorous protection rules, are still recorded. Protective clothing with antistatic properties is designed to prevent the transfer of electrical charge from human operator to electronic device during the manufacturing process. In this chapter, a study was conducted about the electrical parameters representative for the control of electrostatic discharges as well as the surface and volume resistivity by applying the current absorption-resorption method and parameters of charge decay using the standardized induction method on several knitted conductive fabrics with carbon yarn. Current absorption-resorption method is applied for the first time in research under antistatic and dissipative fabrics

Assessment of voltage quality indicators in unbalanced and harmonic distorted regime

This paper deals with the development of a model for assessment of the indicators, which characterize the unbalanced and harmonic distorted operation regime in the three-phase low voltage networks. The symmetrical components transformation and the Fourier method are applied, in which each harmonic is decomposed into zero, positive and negative sequence components. The quality indicators in voltage distorted and unbalanced regime are obtained using MathCAD software. The proposed model and procedure is applied for specific case studies. This approach allows the identification and analysis of distorted and unbalanced regime indicators of three-phase low voltage supply system in common coupling point of the consumer, and the procedure can be integrated into a power quality monitoring system

XIX Міжнародна молодіжна науково-практична конференція «Історія розвитку науки, техніки та освіти» за темою «Фізика та формування нової світової реальності»

The paper brings arguments for the introduction History of Science, Technics and Technology as an optional discipline in the university curriculum. In order to clarify the issues of this discipline, the meaning and significance of some fundamental concepts are detailed, such as: value, culture, civilization, technics, technology. It is analyzed the context in which cultures and civilization have evolved and how can be described the connection between these concepts and science , technics and technology

Multiple Stress Life Analysis on Underground Power Cables from Distribution Networks

Part 11: EnergyInternational audienceThe implementation of underground distribution lines has grown significantly over the last decades due to the rapid increase of electric energy demand. But, the life of underground lines is determined by strong single or multiple stresses, developed during manufacturing and operation. Establishing and predicting the end of life of a distribution underground line is a task for researchers, designers and manufacturers, too. In this respect, the multiple stress life analysis may be used as efficient tool to predict the life of lines and cables. In this paper, a multiple stress analysis is developed, applying the Arrhenius-Weibull life-stress model, in order to identify the effects of multiple stresses on power cables. An application to an underground power line in a Romanian Electric Network Company is developed, in ALTA software package. The multiple stresses of temperature, humidity, and vibrations are considered, and the life distributions and reliability plots are obtained

Modeling and simulation of the PTC heater used in automotive

At present, efforts are made to improve the passenger’s thermal comfort inside the vehicle. The thermal comfort level depends on the air conditioning and heating system. The conventional heating systems use the heat excess delivered by the vehicle’s engine. Nevertheless, this heat excess is insufficient for warming the interior air to a comfort level. In order to improve the conventional heating method, auxiliary heating devices are required. The paper deals with the analysis and measurement of the PTC heater characteristics. A test-bench is described. The heating process inside the vehicle is analyzed and a model and simulations are also presented

A New Washable UHF RFID Tag: Design, Fabrication, and Assessment

This paper deals with the design and fabrication of durable radio frequency identification (RFID) passive tag with inductive coupling, operating at ultra-high frequencies, dedicated to the identification and monitoring of professional textile products. A reliable architecture for the tag transponder is proposed, featuring a minimal number of galvanic contacts: The two pins of the integrated circuit are connected to the terminals of the inductive coupling loop by using surface mount technology welding. The transponder is encapsulated with an electrically insulating material which is waterproof and resistant to mechanical, thermal, and chemical stress. The antenna is inductively coupled to the transponder through a double loop which substantially reduces the length of the tag and significantly improves the coupling factor, enabling the tag to operate at a low power level. The reliability and flexibility of the tag is obtained by using appropriate materials and manufacturing methods for the ultra-high frequency (UHF) antenna by embroidering a multifilament stainless steel wire on textile support. The washing cycle tests have validated the applicability of this flexible and washable RFID tag, and its electromagnetic performance was experimentally assessed in an independent laboratory

Software application for unbalanced regime analysis in three phase low voltage networks

The paper deals with the analysis of unbalance regime in three-phase low voltage supply systems. For unbalance evaluation a virtual instrument realized in Java programming language was developed. This tool can be used in protection schema for the electric distribution network, especially in the common point of supplying the industrial consumers, where the electric equipments can be severely affected by continuously functioning in an unbalanced regime of the power supply. The case study includes determination and analyzes of the unbalance indicators for inductive consumers with and without neutral conductor