Power Transmission and Distribution The most powerful AC Power Transmission System Gas Insulated Transmission Lines
Contents 25 Years of Proven Experiences Second Generation Design and Technical Data Outdoor Installation Tunnel Installation Directly Buried Conclusions
References Worldwide 1974-2004 Installed phase length: 110 km world-wide
Principle Principle: Gas Gas insulated bus bus ducts are are welded up up to to the the desired length
Reference: Wehr, Germany Operation since 1975, Tube Length 4 km 1 600 MVA Transformer Rated Voltage 420 kv 2 Encapsulated Surge Arrestors Rated Impulse 3 Transfer Switching units Withstand Voltage 1640 kv 4 Connection Rated Current 2000 A 5 Open Air Surge Arrestor Rated Short-Time Current 53 ka 6 Overheadline 3,5 m 2,8 5 4
Reference: Bowmanville, Canada Operation since: 1985-87, Length 2.5 km Rated Voltage 550 kv Rated Impulse Withstand Voltage 1550 kv Rated Current 4000 / 6300 / 8000 A Rated Short-Time Current 100 ka
Reference: Palexpo exhibition Centre, Geneva, Switzerland Commissioning: 2001 Rated RatedVoltage Rated RatedCurrent Rated RatedImpulse Withstand WithstandVoltage Rated RatedShort-Time Current Current 300 300 kv kv 2000 2000 A 1050 1050 kv kv 50 50 ka, ka, 1s 1s
Contents 25 Years of Proven Experiences Second Generation Design and Technical Data Outdoor Installation Tunnel Installation Directly Buried Conclusions
Improvements of the Second Generation Overall cost cost reduction of of > 50% 50% compared to to first first generation by: by: Standardization of of components: Modular design design for for tailor-made installations Improvements of of assembly and and laying laying procedure --Pipeline laying laying technique for for short short installation time time --Automated orbital orbital welding machine for for high high quality quality welds welds -Elastic bending of of tubes tubes to to follow follow the the route route Reduction of of SF SF 6 content 6 content to to 20% 20% Cost Cost reduction and and environmental protection by by using using nitrogen as as a majority gas gas
automated welding Ensures absolute gas tightness Enables reproducable high quality, low cost welding
automated welding
Contents 25 Years of Proven Experiences Second Generation Design and Technical Data Outdoor Installation Tunnel Installation Directly Buried Conclusions
Technical Data of the Standard Design Rated Ratedvoltage 420 420 // 550 550 kv kv Impulse withstand voltage 1425 1425 // 1600 1600 kv kv Rated Ratedcurrent up up to to 4000 4000 A Rated Ratedshort-time current 63 63 ka ka // 3 s Rated Ratedtransmission load load up up to to 3500 3500 MVA MVA Overload capability (typical) up up to to 100 100 % Insulation gas gas N 2 /SF 2 /SF 6 mixture 6 at at 0.7 0.7 Mpa Mpa Designed and and tested testedaccording to to IEC IEC 61640 61640 HV HV gasinsulated transmission lines linesfor forrated ratedvoltages of of 72.5 72.5 kv kv gas- and and above
units Generally Generally 4 4 different different component component types types are are required required to to build build a a Gas Gas Insulated Insulated Transmission Transmission Line! Line! Straight Module Angle Module Disconnector Module Compensator Module
Straight Unit --Typical Typicallength lengthof of 120 120 m --Bending Bending radius radiusdown down to to 400 400 m 1 enclosure 2 inner conductor 3 conical insulator 4 support insulator 5a male sliding contact 5b female sliding contact 350 ft 5b 5a 3 4 1 2 4 5b
Angle Unit --for fordirectional directionalchanges changes --flexible flexible angle angle from from4 4 to to 90 90 1 enclosure 2 inner conductor 3a male sliding contact 3b female sliding contact 4 conical insulator 5 support insulator 350 ft 3b 3a 4 1 2 5 5 3a
Disconnector Unit --Segregation Segregation of of gas gas compartments compartments --Enables Enablessectional sectional commissioning commissioning --Location Location of of the the decentralized decentralized monitoring monitoring units units 1 enclosure 2 inner conductor 3a male sliding contact 3b female sliding contact 4 conical insulator 5 support insulator < 120 m 3b 3a 1 4 2 3b 3a 4 5 3b
Compensation Unit --Compensation Compensation for for the the thermal thermal expansion expansion of of the the enclosure enclosure --Flexible Flexible connectors connectors are are carrying carryingthe the current current 1 enclosure 2 inner conductor 3a male sliding contact 3b female sliding contact 4 conical insulator 5 flexible connector 6 compensator bellow 1 2 6 5 3b 3a 4
Features of (part 1) High High ampacity Low Low transmission losses losses Low Low capacitance, no no compensation necessary High High reliability No No practical ageing ageing of of components (CIGRE)
Features of (part 2) Very Verylow lowmagnetic fields, fields, no no electrical field fieldoutside High High operational safety: safety: --no no external influence in in the thecase caseof of an an internal failure failure --no no fire firerisk risk Operation similar similarto to overhead lines lineswith withautoreclosure more morethan than30 30 years yearsof of experience with withgas insulated systems
Magnetic Field Calculation for and Cable Rated Current: 2500 A.5 10. 1. 20. 2. 50. 5. 10. 200. 100. 20. 500. 1000
Magnetic Field Calculation for OHL 5. 5. 10. 10. 20. 20. 20. 20. 5. 5. 20. 20. 10. 10. 50. 50. 50. 50. 500. 500. 200. 200. 100. 100. 500. 500. 200. 200. 100. 100. 20. 20. 5. 5. 200. 200. 200. 200.
600 W/m 500 400 Transmission Losses: Comparison of, Overhead Line, and Cable OHL 4x240/40 Al/St 300 200 100 XLPE Cable 2XKLDE2Y1x1600 0 500 1000 1500 2000 2500 350 700 1000 1400 A MVA 1800
Features No ageing of of the components: Insulators Enclosures and and conductors Insulation gas gas Source: Source: Long Long Term Term Performance Performance of of SF SF 6 Insulated 6 Insulated Systems, Systems, Cigre CigreTF TF 15.03.07, 15.03.07, Cigre CigreSession 2002 2002 No ageing of of N 2 No ageing of of No lifetime limit for systems!
Internal Arc Fault as Part of Type Test View Viewinside insidethe the Test Conditions: Test Conditions: 63 63kA, ka,500ms 500ms No Noexternal externalimpact impact Enclosure Low Lowpressure pressureincrease increase No Nofire firerisk riskdue dueto tonon non inflammable materials inflammable materials Conductor
Contents 25 Years of Proven Experiences Second Generation Design and Technical Data Outdoor Installation Tunnel Installation Directly Buried Conclusions
outdoor installaion
Possible outdoor layout
outdoor arrangement
Contents 25 Years of Proven Experiences Second Generation Design and Technical Data Tunnel Installation Directly Buried Conclusions
Arrangement in a Tunnel
Laying and Commissioning in the Tunnel Principle drawing 1 Delivery and supply of prefabricated elements 2 Mounting and welding 3 Pulling the into the tunnel 4 High voltage test
Contents 25 Years of Proven Experiences Second Generation Design and Technical Data Tunnel Installation Directly Buried Conclusions
Directly Buried
Directly Buried Laying Process
Directly Buried Orbital Welding and Backfill in the Trench
Contents 25 Years of Proven Experiences Second Generation Design and Technical Data Tunnel Installation Directly Buried Conclusions
Conclusion Siemens has more than 30 30 years of of experience Up Up to to now no no major failure occurred is is easy to to operate and it it combines technical advantages with low operation and life life cycle costs. is is the future high power, long distance AC underground transmission system!
Comparison Cable - Direct Burial XLPE (500 kv) Rated Voltage 420 kv 420 kv Impulse Withstand Voltage 1425 kv 1425 kv Rated Current 1350 A (no forced cooling) 2700 A Rated Short Time Current 50 ka, 0.5 s 63 ka, 1 s Rated Transmission Load 1000 MVA (cos phi=1) 2000 MVA (cos phi=1) Insulation XLPE N 2 /SF 6 Mixture Cross Section 2500 mm² Cu 5500 mm² Al Max. Operational Temperature 90 C (conductor) 100 C (conductor) Overload Capacity Max. 1.2 Up to 2
Comparison Cable - Other Criteria Degrading of Insulation 30 years Autoreclosing Capacity No Yes Maintenance Cycle Repair Down-time (max. in case of conductor interruption) 2 years (corrosion protection) - (gaseous insulation) 2 weeks 2 weeks 2 years (corrosion protection)
Earthquake Issues Seismic calculations show that earthquakes do do no no harm to to installations