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Edit Comment Close Premium member Presentation Transcript TECHNICAL TRENDS IN MEDIUM VOLTAGE URD CABLE MATERIALS AND DESIGN : TECHNICAL TRENDS IN MEDIUM VOLTAGE URD CABLE MATERIALS AND DESIGN Joseph H. Dudas Consultant URD Power Cable Early URD Cable Design: Early URD Cable DesignHigh Molecular Weight Polyethylene: High Molecular Weight Polyethylene Seemed impervious to moisture Higher AC breakdown strength Superior dielectric properties Expected 50 plus years life Reduced insulation thicknessCrosslinked Polyethylene (XLPE): Crosslinked Polyethylene (XLPE) Gained favor in late 1960’s Higher mechanical strength Higher operating temperature Higher AC breakdown strength Reduced insulation to 175 milsIndustry Surprised By Early Cable Failures: Industry Surprised By Early Cable Failures Failures of HMWPE in 7 to 10 years Lawson & Vahlstrom first published in 1970 Tree-like structures in failed cables Determined to be electrochemical or water treesElectrochemical Tree in Failed Cable: Electrochemical Tree in Failed CableCable Specifications Tighten: Cable Specifications Tighten Specification groups become active Extruded shields were required Contaminants limited to 10 mils Wet electrical aging test added Protective jackets recommended1970’s Cable Extrusion Technology Was Limited : 1970’s Cable Extrusion Technology Was Limited Industry Status By Late 1970’s: Industry Status By Late 1970’s HMWPE cables failing at 5 per 100 mi. XLPE cable failing at 1 per 100 mi. First commercial Tree Retardant HMWPE Rapid acceptance by Rural Electric Coops IOU’s mainly favored XLPE, others EPR1980’s Brought Significant Changes: 1980’s Brought Significant Changes Dry nitrogen curing process was introduced Strippable XLPE semicon shield developed Extrusion technology improved. Triple Tandem Extrusion Technology : Triple Tandem Extrusion Technology More 1980’s Significant Improvements: More 1980’s Significant Improvements Contamination was reduced significantly Contaminant size reduced from 10 to 5 mils Commercial TRXLPE introduced. Strand filled cables are commercialized More 1980’s Significant Events: More 1980’s Significant Events Jackets gain widespread acceptance Supersmooth Conductor shield developed EPR emerges to compete with TRXLPE What choices to Make?: What choices to Make? What insulation? XLPE, TRXLPE, or EPR? Should we specify strand filled conductor? Are supersmooth conductor shields really better? Should dry cure and triple extrusion be specified? Should a jacket be required? What type?25 Largest Investor Owned Utilities: 25 Largest Investor Owned Utilities Served 1 million or more customers More than 25,000 miles of installed cable 19 of 25 had representatives on AEIC Rank Company No. Cust.: Rank Company No. Cust. 1 Pacific Gas & Electric 4,257,121 2 Southern California Edison 4,078,534 3 Florida Power & Light 3,263,360 4 Commonwealth Edison 3,249,162 5 Consolidated Edison of NY 2,943,281 6 TU Electric 2,176,549 7 Detroit Edison 1,941,881 8 Public Service Elect. & Gas 1,867,453 9 Virginia Electric & Power 1,805,645 10 Duke Power 1,662,168 Cable Specifications Analyzed: Cable Specifications Analyzed Filled strand Conductor shield materials Insulation materials Extrusion method Curing method Metallic shield type Jacket type & materialIncreased use of Filled Stand Conductor over a 15-year period - 25 Largest IOU’s: Increased use of Filled Stand Conductor over a 15-year period - 25 Largest IOU’sInsulation Materials Specified: Insulation Materials Specified TRXLPE EPR XLPEInsulation Compounds Specified over a 15-Year Period: Insulation Compounds Specified over a 15-Year PeriodDual Use Utilities Emerged Strongly in 1998: Dual Use Utilities Emerged Strongly in 1998Primary Reasons Cited for Specifying TRXLPE: Primary Reasons Cited for Specifying TRXLPE Lower cost Excellent service life Lower electrical losses Primary Reasons Cited for Specifying EPR: Primary Reasons Cited for Specifying EPR Long service life Better flexibility Less expansion during heating Better properties at high temperatureSupersmooth Semiconducting Conductor Shield Materials: Supersmooth Semiconducting Conductor Shield Materials Introduced in 1988 Formulated from acetylene carbon black Finer particle size Increased cable lifeIncreased use of Supersmooth Semiconducting Compound over a 10-Yr. Period - 25 Largest IOU’s: Increased use of Supersmooth Semiconducting Compound over a 10-Yr. Period - 25 Largest IOU’sCable Extrusion Methods: Cable Extrusion MethodsTriple Extrusion Specified over a 15-year period: Triple Extrusion Specified over a 15-year periodCuring Method Specified: Curing Method Specified Dry Nitrogen Steam Curing method not specifiedDry Nitrogen Curing Specified over a 15-year period: Dry Nitrogen Curing Specified over a 15-year periodMetallic Shielding: Metallic Shielding Concentric copper wires Flat strap Longitudinal corrugated shieldCopper Neutral Type Specified by 25 Largest IOU’s 1998: Copper Neutral Type Specified by 25 Largest IOU’s 1998Advantages of a Protective Jacket: Advantages of a Protective Jacket Safeguard metallic shield from corrosion Reduce mechanical damage Barrier to water penetrationIncreased use of Cable Jackets Over a 15-year period: Increased use of Cable Jackets Over a 15-year periodProtective Jacket Types: Protective Jacket TypesCable Jacket Type Specified by 25 Largest IOU’s 1998: Cable Jacket Type Specified by 25 Largest IOU’s 1998Cable Jacket Compound Specified by 25 Largest IOU’s - 1998: Cable Jacket Compound Specified by 25 Largest IOU’s - 1998Most Widely Specified 15-35kV Cable Constructions: Most Widely Specified 15-35kV Cable Constructions Filled strand for non solid conductors TRXLPE or EPR insulation compound Supersmooth semicon cond shld for TRXLPE 1+2 triple or 3 in 1 triple extruded Dry cured for TRXLPE Concentric wire or Conc/LC 600A metallic shield Encapsulating insulating PE jacket Typical USA Medium Voltage Cable: Typical USA Medium Voltage CableREFERENCES: REFERENCES Early history and technical trends of IOU’s in March/April 1994 issue of Electrical Insulation Magazine. Technical trends of IOU's is in ICC Fall 1999 minutes and Nov/Dec 1999 issue of Electrical Insulation Magazine. Technical Trends of REC’s in ICC Fall 1998 minutes and 1998 proceedings of Rural Electric Power Conference Eight Utilities Specifying EPR Insulation: Eight Utilities Specifying EPR Insulation 5 Specify Filled Strand None specify Supersmooth Strand Shield 2 specify 1 + 2 triple extrusion None specify the curing method 8 specify jackets You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.
fall02dudas Lilly Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINTLite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 453 Category: Entertainment License: All Rights Reserved Like it (1) Dislike it (0) Added: December 04, 2007 This Presentation is Public Favorites: 0 Presentation Description No description available. Comments Posting comment... By: Eng. (45 month(s) ago) I'm engineer worked in Saudi Electricity Company and I'm interested of High Voltage Underground Cable field. so, I hope to give me validity to download if you want. and I promise, any useful document('s), I will uploaded immediatly. Saving..... Post Reply Close Saving..... Edit Comment Close Premium member Presentation Transcript TECHNICAL TRENDS IN MEDIUM VOLTAGE URD CABLE MATERIALS AND DESIGN : TECHNICAL TRENDS IN MEDIUM VOLTAGE URD CABLE MATERIALS AND DESIGN Joseph H. Dudas Consultant URD Power Cable Early URD Cable Design: Early URD Cable DesignHigh Molecular Weight Polyethylene: High Molecular Weight Polyethylene Seemed impervious to moisture Higher AC breakdown strength Superior dielectric properties Expected 50 plus years life Reduced insulation thicknessCrosslinked Polyethylene (XLPE): Crosslinked Polyethylene (XLPE) Gained favor in late 1960’s Higher mechanical strength Higher operating temperature Higher AC breakdown strength Reduced insulation to 175 milsIndustry Surprised By Early Cable Failures: Industry Surprised By Early Cable Failures Failures of HMWPE in 7 to 10 years Lawson & Vahlstrom first published in 1970 Tree-like structures in failed cables Determined to be electrochemical or water treesElectrochemical Tree in Failed Cable: Electrochemical Tree in Failed CableCable Specifications Tighten: Cable Specifications Tighten Specification groups become active Extruded shields were required Contaminants limited to 10 mils Wet electrical aging test added Protective jackets recommended1970’s Cable Extrusion Technology Was Limited : 1970’s Cable Extrusion Technology Was Limited Industry Status By Late 1970’s: Industry Status By Late 1970’s HMWPE cables failing at 5 per 100 mi. XLPE cable failing at 1 per 100 mi. First commercial Tree Retardant HMWPE Rapid acceptance by Rural Electric Coops IOU’s mainly favored XLPE, others EPR1980’s Brought Significant Changes: 1980’s Brought Significant Changes Dry nitrogen curing process was introduced Strippable XLPE semicon shield developed Extrusion technology improved. Triple Tandem Extrusion Technology : Triple Tandem Extrusion Technology More 1980’s Significant Improvements: More 1980’s Significant Improvements Contamination was reduced significantly Contaminant size reduced from 10 to 5 mils Commercial TRXLPE introduced. Strand filled cables are commercialized More 1980’s Significant Events: More 1980’s Significant Events Jackets gain widespread acceptance Supersmooth Conductor shield developed EPR emerges to compete with TRXLPE What choices to Make?: What choices to Make? What insulation? XLPE, TRXLPE, or EPR? Should we specify strand filled conductor? Are supersmooth conductor shields really better? Should dry cure and triple extrusion be specified? Should a jacket be required? What type?25 Largest Investor Owned Utilities: 25 Largest Investor Owned Utilities Served 1 million or more customers More than 25,000 miles of installed cable 19 of 25 had representatives on AEIC Rank Company No. Cust.: Rank Company No. Cust. 1 Pacific Gas & Electric 4,257,121 2 Southern California Edison 4,078,534 3 Florida Power & Light 3,263,360 4 Commonwealth Edison 3,249,162 5 Consolidated Edison of NY 2,943,281 6 TU Electric 2,176,549 7 Detroit Edison 1,941,881 8 Public Service Elect. & Gas 1,867,453 9 Virginia Electric & Power 1,805,645 10 Duke Power 1,662,168 Cable Specifications Analyzed: Cable Specifications Analyzed Filled strand Conductor shield materials Insulation materials Extrusion method Curing method Metallic shield type Jacket type & materialIncreased use of Filled Stand Conductor over a 15-year period - 25 Largest IOU’s: Increased use of Filled Stand Conductor over a 15-year period - 25 Largest IOU’sInsulation Materials Specified: Insulation Materials Specified TRXLPE EPR XLPEInsulation Compounds Specified over a 15-Year Period: Insulation Compounds Specified over a 15-Year PeriodDual Use Utilities Emerged Strongly in 1998: Dual Use Utilities Emerged Strongly in 1998Primary Reasons Cited for Specifying TRXLPE: Primary Reasons Cited for Specifying TRXLPE Lower cost Excellent service life Lower electrical losses Primary Reasons Cited for Specifying EPR: Primary Reasons Cited for Specifying EPR Long service life Better flexibility Less expansion during heating Better properties at high temperatureSupersmooth Semiconducting Conductor Shield Materials: Supersmooth Semiconducting Conductor Shield Materials Introduced in 1988 Formulated from acetylene carbon black Finer particle size Increased cable lifeIncreased use of Supersmooth Semiconducting Compound over a 10-Yr. Period - 25 Largest IOU’s: Increased use of Supersmooth Semiconducting Compound over a 10-Yr. Period - 25 Largest IOU’sCable Extrusion Methods: Cable Extrusion MethodsTriple Extrusion Specified over a 15-year period: Triple Extrusion Specified over a 15-year periodCuring Method Specified: Curing Method Specified Dry Nitrogen Steam Curing method not specifiedDry Nitrogen Curing Specified over a 15-year period: Dry Nitrogen Curing Specified over a 15-year periodMetallic Shielding: Metallic Shielding Concentric copper wires Flat strap Longitudinal corrugated shieldCopper Neutral Type Specified by 25 Largest IOU’s 1998: Copper Neutral Type Specified by 25 Largest IOU’s 1998Advantages of a Protective Jacket: Advantages of a Protective Jacket Safeguard metallic shield from corrosion Reduce mechanical damage Barrier to water penetrationIncreased use of Cable Jackets Over a 15-year period: Increased use of Cable Jackets Over a 15-year periodProtective Jacket Types: Protective Jacket TypesCable Jacket Type Specified by 25 Largest IOU’s 1998: Cable Jacket Type Specified by 25 Largest IOU’s 1998Cable Jacket Compound Specified by 25 Largest IOU’s - 1998: Cable Jacket Compound Specified by 25 Largest IOU’s - 1998Most Widely Specified 15-35kV Cable Constructions: Most Widely Specified 15-35kV Cable Constructions Filled strand for non solid conductors TRXLPE or EPR insulation compound Supersmooth semicon cond shld for TRXLPE 1+2 triple or 3 in 1 triple extruded Dry cured for TRXLPE Concentric wire or Conc/LC 600A metallic shield Encapsulating insulating PE jacket Typical USA Medium Voltage Cable: Typical USA Medium Voltage CableREFERENCES: REFERENCES Early history and technical trends of IOU’s in March/April 1994 issue of Electrical Insulation Magazine. Technical trends of IOU's is in ICC Fall 1999 minutes and Nov/Dec 1999 issue of Electrical Insulation Magazine. Technical Trends of REC’s in ICC Fall 1998 minutes and 1998 proceedings of Rural Electric Power Conference Eight Utilities Specifying EPR Insulation: Eight Utilities Specifying EPR Insulation 5 Specify Filled Strand None specify Supersmooth Strand Shield 2 specify 1 + 2 triple extrusion None specify the curing method 8 specify jackets