The paper describes the problem of electromagnetic compatibility for electrostatic discharge (ESD), which is most actual for ships where all systems are highly automated and susceptible to ESD digital technology. The results of electromagnetic compatibility tests of ship systems after their installation on the vessel allow to conclude that it is not enough to fulfill only the existing ESD immunity requirements of the Russian Maritime register of shipping which are currently confirmed by ESD tests in the laboratory. ESD methods and reasons have been analyzed. The possible accumulated potentials and parameters of currents, voltages and field strengths during discharge are presented. The existing ESD immunity standards are being considered. The scheme of the developed and certified generator of electrostatic discharges ESD – 25000 is presented. The most frequent defects under the influence of ESD are given. There have been formulated the equivalent schemes of the electric equipment housing at different lengths of grounding of the housing and the methods of connecting the cover with the housing. The results of measurements of electric field and magnetic field parameters are presented. The results of modeling and experiments are compared. The developed sensors, methods of their calibration and obtained technical characteristics are being tested. There are given the parameters and forms of ESD voltage and current, experimental data of ESD secondary effects in the EE hull and adjacent equipment, results of discharges in the ship's cable, interference in the supply network through secondary power sources. The most effective design and ESD protection methods have been analyzed
Low frequency common mode voltages can produce malfunction of control and measuring systems. The sources of common mode voltages are electrical equipment, semiconductor converters and secondary supply units. Common mode voltage can be more than 140 V on output of secondary supply units with transformer and more than 30 V on input terminal of frequency converter.
It is necessary to take into consideration nanosecond pulse propagation in bursts immunity tests and in EMC research work. Electrical cable between pulse noise source and equipment influences on malhnction level. The model of pulse propagation in time domain is used for calculafion. Parameters of power cables for the model and effects of propagation are discussed. IntroduciionNanosecond pulses are generated in electrical system in commutation processes. Pulses can lead to malfunction of eiectronic equipment. Amplitude and duration of pulses on the equipment depend on propagation in power cables. The propagation parameters for power cables are not investigated enough. Time constants are not determined. It is important to take into consideration wave effects in cables. Calculation of the time constants is presented for different KNR type cables and for different cable lengths. Calculation of pulse parameters for the line with change of height above steel construction is given in the paper. Propagation effects in cablesIt is possible to distinguish the following cables effects which determines pulse parameters during propagation:-Attenuation of pulse due to losses. -Change value of wave. impedances along a propagation way. r -for losses only in dielectric , l Time parameters tM and r, can be calculated with the following expressions: 2 A2 rM = roMl ; roM = -for Bf = 0, ?r B z, , = rOD1 ; zOD = -for A-& = 0, 3t where zOM is constant time for metal losses (s/ km'), To, is time constant for dielectric losses ( s h ' ) . Parameters70M,ronand length of a cable 1 determine an attenuation in metal and in dielectric. It is not necessary to consider dielectric losses if the following ratio is close to zero [2]: -' D 2 --=-+O,where *OD 1 m=-'OM 2. Attenuation effect TM 'COM.1 m.1 f O DThe attenuation coefficient in frequency domain has three components:The result of calculation (table 1, fig. 1) shows, that the increasing of square sections of cables f?om lmm2 up to 240"' influence on ZoD less, than on T O M . a = A f i + B f +a,,where'the first component characterizes losses in metal, coeficients =4.76.10-8(~~~2), rooo =3.92, the second component -losses in dielectric, and the last one -losses for direct current [ 11.The step response ofthe cable cm be defined by h e ( s h ' ) and m is equal to 250 for the cable KNR 3x1 " ' 9 but =9.8.10-7 (sh2)s rOD =4*29*10-9(slkm2) --following formula: and m=ll for the cable KNR 3x240 m2 ( fig. la,b); It means that it is not necessary to consider dielectric losses in short low current cables.-for losses only in metal 0-7803-9374~0/05/%20.00 6 2005 IEEE
Undegraduate EMC course for tlectrical engineering profession was established in Leningrad shipbuilding institute (now -Leningrad State University of Ocean Technology) in 1987. The course includes 51 hours lectures and 34 hours laboratory experiaents. The students have t o carry 10 labs on original equipment. Individuality, coupling of labs, comparison of experiments and calculation, "making by hands' are basic principles t o increase effeciency of training. The students have to defend their conclusions based on experiments, calculations and personal computer simulation. ERC course Electrical engineer's education in Leningrad State University of Ocean Technology includes ERC course. The students study EHC on the 9-th semester for E5 hours. They have t o learn fumdamental principles of electrical circuits, electrical. systems, electronics, converters before this course.The outline of t h e course is t h e following: Generation of pulse voltages, noise and harmonics in electrical systems. Propagation of voltage pulses and noise in ships. Design for ERC (filtering, placement of cables and equipment, shielding, grounding etc.). Reasurerents. Testing. Standards and ERC requiraents.Effeciency of ERC training depends on quantity and quality of laboratory exersises. The students have to feel reality of pulse and noise generation, susceptibility of electronic equipment. Ten labs help the students to acquire the skill in measuring, testing, noise suppression and protection.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.