2. INTRODUCTION TO GIL
Gil are composed of pipes that houses conductors in SF6 gas.
Gil are good alternative for transmission of extra high voltage(EHV).
Gil are used for both underground and overhead transmissions.
3. WHY ONLY SF6 RATHER THAN AIR?
Electronegativity.
Dielectric strength.
Arc quenching ability.
8. LAYOUT METHODS FOR INSTALLATIONS
OF GIL
1. Aboveground installation.
2. Direct burial installation.
3. Vertical installation.
4. Tunnel installation.
9. 1.ABOVE GROUND INSTALLATION
• Gil are unaffected by high
ambient temperature ,
intensive solar radiation or
severe atmospheric
pollution.
• Corrosion protection is not
required.
10. 2.DIRECT BURIAL INSTALLATION
• These systems are coted with
continuous polyethylene to
safeguard corrosion resistant
aluminum alloy.
• The land can be used for
irrigation with minor
restrictions.
11. 3.VERTICAL INSTALLATION
• Gas insulated tubular
conductors can be installed
without a problem at any
gradient ,even vertically.
• These are top solution
especially for cavern
hydropower plant.
12. 4.TUNNEL INSTALLATION
• The system stays accessible
for easy inspection and high
transmission capacity is
ensured.
• They can installed in a
tunnel or shaft.
13. ADVANTAGES
• High transmission capacity
• Low transmission losses
• Low capacitance
• High reliability
• High operational safety (no fire risk, no external impact in case of internal failures).
• No practical ageing of components
• Very low external magnetic field
• No interference with the communication systems
14. DISADVANTAGES
• Length of each GIL section is limited.
• Earthquake resistant design must be considered.
• SF6 gas is harmful to ozone.
15. APPLICATIONS
• Most of the installations are in tunnels.
• Ideal for environments that are sensitive to electro-magnetic fields.
• Suitable for metropolitan areas where high energy rate is required.
• Well suited for high power transmission.
16. Future applications
• Long Distance AC-GIL.
• Trans European Networks.
• Offshore Wind farms.
• Improved Reliability of Electric Power.