摘要 :
Changing environmental interests and new fire safety performance concerns in the wire and cable industry (WCI) have generated studies into the fire hazard and eco-performance of various data and communication cabling system altern...
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Changing environmental interests and new fire safety performance concerns in the wire and cable industry (WCI) have generated studies into the fire hazard and eco-performance of various data and communication cabling system alternatives for computers and local area networks (LAN). To accurately assess the various alternatives, the installed electronic functionality and fire safety performance requirements of the various end-use product options must be equivalent. For high fire performance communication cables (HFP-cables), many existing local and national regulations differentiate between end product performance options and building fire protection needs. High fire-performance, high societal-value based PVC sheathed and perfluoropolymer (PFP) insulated (PVC/PFP) cables can be routed directly in concealed plenum spaces in buildings, while products that do not meet specific high fire performance criteria, such as low-smoke zero-halogen (LSZH/PE) cables or riser-rated cables (CMR or PVC/PE), often must be protected inside other structures that do meet these building fire standards, typically using steel conduit or trunking. However, some low fire performance LAN cables, even fire-protected inside steel conduits, failed to meet the minimum flame spread and smoke criteria that HFP-cables must meet in real-scale cable, fire tests at BRE/FRS and Underwriters Laboratories (when tested as a cable in steel conduit system). Life cycle analysis (LCA) via ISO 14040 methodology is used to evaluate the various cabling alternatives using an appropriate functional unit; a CAT 6 communication LAN cabling system in a typical office building, including cable, steel conduit, couplings and supports as required per building codes for the installation. Key environmental impact assessments for energy consumption, greenhouse gas emissions, and human toxicity are all shown to favor the PVC/PFP systems once the steel conduit is included in the analysis to fire-protect the LSZH/PE or PVC/PE cables. The additional fire safety and installation advantages provided by the PVC/PFP cables more than offsets for the environmental burdens associated with the initial manufacture of just the cable, thereby providing superior overall fire safety, environmental performance, and economic benefits versus LSZH/PE and PVC/PE cables in steel conduits.
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摘要 :
Changing environmental interests and new fire safety performance concerns in the wire and cable industry (WCI) have generated studies into the fire hazard and eco-performance of various data and communication cabling system altern...
展开
Changing environmental interests and new fire safety performance concerns in the wire and cable industry (WCI) have generated studies into the fire hazard and eco-performance of various data and communication cabling system alternatives for computers and local area networks (LAN). To accurately assess the various alternatives, the installed electronic functionality and fire safety performance requirements of the various end-use product options must be equivalent. For high fire performance communication cables (HFP-cables), many existing local and national regulations differentiate between end product performance options and building fire protection needs. High fire-performance, high societal-value based PVC sheathed and perfluoropolymer (PFP) insulated (PVC/PFP) cables can be routed directly in concealed plenum spaces in buildings, while products that do not meet specific high fire performance criteria, such as low-smoke zero-halogen (LSZH/PE) cables or riser-rated cables (CMR or PVC/PE), often must be protected inside other structures that do meet these building fire standards, typically using steel conduit or trunking. However, some low fire performance LAN cables, even fire-protected inside steel conduits, failed to meet the minimum flame spread and smoke criteria that HFP-cables must meet in real-scale cable fire tests at BRE/FRS and Underwriters Laboratories (when tested as a cable in steel conduit system) [10]. Life cycle analysis (LCA) via ISO 14040 methodology is used to evaluate the various cabling alternatives using an appropriate functional unit; a CAT 6 communication LAN cabling system in a typical office building, including cable, steel conduit, couplings and supports as required per building codes for the installation. Key environmental impact assessments for energy consumption, greenhouse gas emissions, and human toxicity are all shown to favor the PVC/PFP systems once the steel conduit is included in the analysis to fire-protect the LSZH/PE or PVC/PE cables. The additional fire safety and installation advantages provided by the PVC/PFP cables more than offsets for the environmental burdens associated with the initial manufacture of just the cable, thereby providing superior overall fire safety, environmental performance, and economic benefits versus LSZH/PE and PVC/PE cables in steel conduits.
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摘要 :
Changing environmental interests and new fire safety performance concerns in the wire and cable industry (WCI) have generated studies into the fire hazard and eco-performance of various data and communication cabling system altern...
展开
Changing environmental interests and new fire safety performance concerns in the wire and cable industry (WCI) have generated studies into the fire hazard and eco-performance of various data and communication cabling system alternatives for computers and local area networks (LAN). To accurately assess the various alternatives, the installed electronic functionality and fire safety performance requirements of the various end-use product options must be equivalent. For high fire performance communication cables (HFP-cables), many existing local and national regulations differentiate between end product performance options and building fire protection needs. High fire-performance, high societal-value based PVC sheathed and perfluoropolymer (PFP) insulated (PVC/PFP) cables can be routed directly in concealed plenum spaces in buildings, while products that do not meet specific high fire performance criteria, such as low-smoke zero-halogen (LSZH/PE) cables or riser-rated cables (CMR or PVC/PE), often must be protected inside other structures that do meet these building fire standards, typically using steel conduit or trunking. However, some low fire performance LAN cables, even fire-protected inside steel conduits, failed to meet the minimum flame spread and smoke criteria that HFP-cables must meet in real-scale cable, fire tests at BRE/FRS and Underwriters Laboratories (when tested as a cable in steel conduit system). Life cycle analysis (LCA) via ISO 14040 methodology is used to evaluate the various cabling alternatives using an appropriate functional unit; a CAT 6 communication LAN cabling system in a typical office building, including cable, steel conduit, couplings and supports as required per building codes for the installation. Key environmental impact assessments for energy consumption, greenhouse gas emissions, and human toxicity are all shown to favor the PVC/PFP systems once the steel conduit is included in the analysis to fire-protect the LSZH/PE or PVC/PE cables. The additional fire safety and installation advantages provided by the PVC/PFP cables more than offsets for the environmental burdens associated with the initial manufacture of just the cable, thereby providing superior overall fire safety, environmental performance, and economic benefits versus LSZH/PE and PVC/PE cables in steel conduits.
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摘要 :
NFPA 70, National Electrical Code (NEC) permits communications and optical fiber cable substitutions based on a fire performance hierarchy. The principle is that cable types higher in the hierarchy are permitted to substitute for ...
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NFPA 70, National Electrical Code (NEC) permits communications and optical fiber cable substitutions based on a fire performance hierarchy. The principle is that cable types higher in the hierarchy are permitted to substitute for cable types that are lower in the hierarchy. The Canadian Electrical Code (CEC) and the National Building Code of Canada (NBCC) which together specify communications cabling requirements in buildings in Canada also have a similar hierarchy. This paper reviews the fire tests used for listing communications cables and optical fiber cables, and the rationale for the cable substitution hierarchies. New test data are presented which show that FT6 rated cables have superior results as compared to the requirements of the FT4 test, thereby supporting the current hierarchy in the Canadian codes.
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Corona in high voltage rotating machines (HVRM) is a very common and might be considered an inevitable phenomenon. Corona has various different signatures, causes, severity, and potential hazard for reliable machine operation. The...
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Corona in high voltage rotating machines (HVRM) is a very common and might be considered an inevitable phenomenon. Corona has various different signatures, causes, severity, and potential hazard for reliable machine operation. The necessity, frequency, and procedure for effective repair are contingent upon proper evaluation of all the issues discussed in this article.
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摘要 :
Corona in high voltage rotating machines (HVRM) is a very common and might be considered an inevitable phenomenon. Corona has various different signatures, causes, severity, and potential hazard for reliable machine operation. The...
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Corona in high voltage rotating machines (HVRM) is a very common and might be considered an inevitable phenomenon. Corona has various different signatures, causes, severity, and potential hazard for reliable machine operation. The necessity, frequency, and procedure for effective repair are contingent upon proper evaluation of all the issues discussed in this article.
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This paper presents the research and development results on surface corona suppression systems in high voltage large generator stator winding end turns. Theoretical analysis on the physical phenomena of the surface corona in stato...
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This paper presents the research and development results on surface corona suppression systems in high voltage large generator stator winding end turns. Theoretical analysis on the physical phenomena of the surface corona in stator end turns is described. The important physical parameters of surface corona suppression systems are discussed. It is shown that at least four physical parameters of a voltage grading system should be considered and optimized to provide the reliable function both at the testing and operation conditions.
Based on the theoretical analysis and practical experiments several designs of such corona suppression systems are developed. More than 1000 practical test results show that these systems are able to suppress surface corona at over 150% to 200 % of operated line to ground voltages.
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Historically, groundwall insulation for high voltage rotating machine (HVRM) stator windings operate at higher electrical stresses for machines with a higher rated voltage. Thus, the insulation thickness is not proportional to the...
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Historically, groundwall insulation for high voltage rotating machine (HVRM) stator windings operate at higher electrical stresses for machines with a higher rated voltage. Thus, the insulation thickness is not proportional to the machine rated voltage. Both mechanical and electrical capabilities of insulation are taken in account to define groundwall insulation thickness based on long term practical experience. With the replacement of an older insulation system with a newer insulation system the aforementioned design concept for insulation wall thickness is preserved. While a newer system usually has increased electrical stresses, the consideration of lower electrical stresses for lower rated voltages usually stays unchanged. In some cases however the newer insulation system may allow for a different approach, but which should be carefully evaluated. The authors have observed that voltage endurance life expectancy for a thinner insulation for high voltage rotating machine stator windings made of a modern insulation based on mica paper and a thermosetting matrix provides the same or better voltage endurance life expectancy as a thicker insulation wall when voltage endurance tests are performed at the same electrical stress. Also mechanical stresses are lower in a thinner insulation if the insulation itself is not a part of the winding structural support. Conversely, for a thinner insulation wall, the impact of a single layer of taped insulation more or less is more significant than for a thicker insulation. This paper considers factors to be taken in to account to design reliable and efficient stator winding ground wall insulation for high voltage rotating machines with different rated voltages.
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摘要 :
Historically, groundwall insulation for high voltage rotating machine (HVRM) stator windings operate at higher electrical stresses for machines with a higher rated voltage. Thus, the insulation thickness is not proportional to the...
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Historically, groundwall insulation for high voltage rotating machine (HVRM) stator windings operate at higher electrical stresses for machines with a higher rated voltage. Thus, the insulation thickness is not proportional to the machine rated voltage. Both mechanical and electrical capabilities of insulation are taken in account to define groundwall insulation thickness based on long term practical experience. With the replacement of an older insulation system with a newer insulation system the aforementioned design concept for insulation wall thickness is preserved. While a newer system usually has increased electrical stresses, the consideration of lower electrical stresses for lower rated voltages usually stays unchanged. In some cases however the newer insulation system may allow for a different approach, but which should be carefully evaluated. The authors have observed that voltage endurance life expectancy for a thinner insulation for high voltage rotating machine stator windings made of a modern insulation based on mica paper and a thermosetting matrix provides the same or better voltage endurance life expectancy as a thicker insulation wall when voltage endurance tests are performed at the same electrical stress. Also mechanical stresses are lower in a thinner insulation if the insulation itself is not a part of the winding structural support. Conversely, for a thinner insulation wall, the impact of a single layer of taped insulation more or less is more significant than for a thicker insulation. This paper considers factors to be taken in to account to design reliable and efficient stator winding ground wall insulation for high voltage rotating machines with different rated voltages.
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