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Standards for Insulating links
ANSI/CPLSO-14
ANSI/UL2737 (Withdrawn)
ASTM F2973
MIL-L-24410 (Withdrawn)
Tests by Independent Organizations
Load Insulator
Miller & Hirtzer
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322 Where: E is the pulse energy 0.5 0.4 U 0) $ 0.3 z 5 0.2 a w 0.1 W z 0.0 0 20 4 60 80 100 ti0 VOLTAGE IN kV Figure 13. Pulse energy through the crane worker link, although not perfect, significantly increases the safety of the crane's operation. REFERENCES 1. H.B. Hamilton, J.D. Morgan, 'Final report on an evaluation of mobile crane safety devices to Bucyus Erie Inc', 1982. Berlin, 2. H.Freiberger,'m 1934, Verlag Julius Springer. 3. G. Begelmeir, K. Rot$r,'Elecbicalresistancesandcurrents in the human body', Electrotechnik and Maschinenbau, 1971, pp 4. G. Biegelmeir, 'New knowledge on the impedance of the human body'. Proceedings of the First International Symposium on Electric Shock Safety Criteria, Pergamon Press, New York, 104-114. Equation 6 has been evaluated and the results are shown in :985hy ~$~~2:wy impedance for transient high voltage currents', Proceedings of the First International Symposium on Figure 13. Electric Shock Safety Criteria, Pergamon Press, 1985, pp. 183- It can be seen that the link provides complete protection against fatalshodc.Also,thelinkprot~tsagainstunconfortableshodcup lg2* is less up to J. Myklebust, A. Sances, Jr., M. Chilbert, T. Prieto, T. Swiontek, %apacitive Discharge Studies', Proceedings of the capacitance is less than 25pF. However, the crane worker suffers minor shodc above 5o kV if the link capacitance is less First International Symposium on Elecbic Shock Safety Criteria, Pergamon Press, 1985, pp. 183-192. than 25pF;above 70 kv if the capacitance is less than loPF and 7. C.F. Dalziel, W.R. Lee, 'Re-evaluation of lethal electric currents', IEEE Trans. lndustry Gen. Appl., IGA-4, pp. 467-477. above 1 OOkV, if the capacitance is less than 5pF. kv if its kV if the 6. CONCLUSION The effectiveness of the insulating link, to protect workers when the crane touches a high-voltage transmission line, has been studied and a calculation method has been developed. The steady-state current effect was analyzed by a model, which simulates the electrical supply,crane link, and the body impedance of the worker. Computer simulation has been used to calculate the transient current pulses generated by the contact between the crane and high-voltage powerline. The effect of these currents on the worker was determined.The summary of the findings are: 1. The model and calculation method, presented in the paper is an efficient tool for the analysis of similar systems. 2. Direct contact between the crane and power line produces a large current, which endangers the worker's life. 3. Use of an insulated protection lin, in clean, dry conditions reduces the steady-state current under the let-go current level and efficiently protects the worker's life. 4. Polluting and wetting the insulator link increases the steady- state current above let-go-level but below the potentially fatal ventricular fibrillation level. 5. Touching a power line producesa large oscillatory transient- current pulse which flows through the crane worker. 6. The transient-current pulse energy is sufficient to cause unconfortable shodc depending on the link capacitance and system voltage. The final result is that the investigation proved that the insulating 8. Transmission Line Reference Book - HVDC to f 600 kV, Electric Power Research Institute, Palo Alto, CA 1983. The author would like to gratefully acknowledge the assistance of Dr. T. Thompson with this research. (SM'70, F78) was born in Budapest, Hungary. He received his BSEE and Doctor of Engineering degree in electrical engineering from Technical University of Budapest in 1952 and 1960 respectively. Dr. Wady was appointed to Salt River Project Chair Professor at Arizona State University in 1986. Previously, he was with EBASCO Services where he served as Chef Consulting Electrical Engineer, Manager of Electrical Systems and Chief Engineer of Computer Technology. He was Electrical Task supervisor for the Tokomak Fusion Test reactor project in Princeton. From 1969 to 1977 he worked for the Hydro Quebec Institute of Research. Between 1952-1 969 he worked for the Technology University of Budapest where he progressed from Post Doctoral Student to Deputy Department Head. Dr. Karady is a registered professional engineer in New York, New Jersey and Quebec. He is the author of more than 80 technical papers. Dr. Karady is a member of the ClGRE U.S. National Committee, where he served as vice president and presently Secretary-Treasurer. He is the Chairman of the IEEE Subcommittee on Lightning and Insulator and WG on Non- Ceramic Insulators.
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