1. 1200 kV AC Substations - Products and Integrated Solutions International UHV Symposium New Delhi, 29. January Edelhard Kynast Siemens AG, Energy

2. 1200 kV AC Substation Basic requirements - Example: PGCIL
Electrical Requirements
Rated voltage kV
Rated current, feeder A
Rated frequency Hz
Short-circuit current 50 kA / 1 s
Rated lightning impulse withstand voltage 2400 kV
Rated switching impulse withstand voltage kV
Creepage distance 25 mm/kV (Total mm)
Environmental conditions
Temperature (min / average / max) +4 ºC / 38 ºC / 50 ºC
Seismic Zone 1
Wind m/s
Altitude <1000 m

3. 1200 kV AC Substation Basic requirements - Example: PGCIL
Minimum Clearances
Minimum clearance phase to earth mm
Minimum clearance phase to phase mm
(According to draft „IEC Amd.1 Ed. 8.0, “)
Lowest part of insulation mm
Min. height lowest live part mm
Working clearance mm
AIS is PGCIL
preferred technology
Assumed distances
Bay distances
Phase to phase distance mm
Bay width mm
Three live part levels
Height of lower conductor level mm
Height of busbar mm
Height of long spans mm

4. 1200 kV AC Substation Circuit Configurations
1 ½ Breaker Configuration
2 Breaker Configuration
Recommended solution:
Double Busbar Configuration
Arrangement is simple and clear
Acceptable costs
Unrestricted and non-stop operation of all feeders in 2 groups
Busbar maintenance without interruption of power supply
more

5. 1200 kV AC Substation Double Busbar arrangement - Layout

6. 1200 kV AC Substation Double Busbar Arrangement - Layout
- Surge Arresters
Disconnectors
Dead Tank Circuit Breakers
Current Transformers
Capacitive Voltage Transformers

7. 1200 kV AC Surge Arresters Development
Based on 800 kV DC-Application
5 unit surge arrester with grading and corona ring
Active part with four columns in parallel
Additional cooling with aluminum blocks between MO varistors
800 kV DC Design

8. 1200 kV AC Surge Arresters Technical Data
Designation 3EQ PT95
Rated voltage kV
Continuous operating voltage 723 kV
Nominal discharge current 20 kA
Lightning impulse protection level 1700 kV
Switching impulse protection level 1500 kV
Energy discharge capability 55 MJ
Creepage distance mm
(30 mm/kV)
Height m
Bending moment kNm
Voltage-current characteristic of a MO surge arrester for 1200 kV AC power system

9. 1200 kV AC Disconnector - Project Powergrid India Recommendation for Double Side Break Design
Double Side Break design advantages for 1200 kV AC application
- high reliability due to the reduced number of moving parts
in the kinematic chain and in the current path
- well proven turn and twist design of the current path
- space savings in the vertical dimension due to the current path
movement only in the horizontal direction
Experience in Double Side Break Disconnectors for UHV application
- Double side break ZBF 800 kV AC in service in Ucraine
- Double side break ZBF 515 kV DC in service in China
- Double side break ZBF 824 kV DC installation in China

10. Technical parameters 1200 kV AC disconnector & earthing switch
1200 kV AC Disconnector Specified Requirements - Project Powergrid India
Technical parameters 1200 kV AC disconnector & earthing switch
Rated voltage 1200 kV
Frequency 50 Hz 
Normal current Amps
Short time withstand current 50 kA / 1 s
Peak withstand current 125 kA
Lightning impulse withstand voltage
- phase- to- earth 2400 kV
- across isolating distance 2400 kV+685 kV
Switching impulse withstand voltage
- phase- to- earth 1800 kV
- across isolating distance 1800 kV + 980kV
Creepage distance of insulators 25 mm/kV
ZBF 824 kV DC, DoubleSideBreak
Project Yun Guang, China

11. UHV - Circuit-Breaker 1200 kV Testing: Short circuit performance
8DR1-P kV – 50 kA
Test at KEMA, Arnhem , February / April 2008
T100a (February 2008)
Full pole test
Time constant 120 ms
Value of last current loop 115 kA
First pole to clear factor 1,3 p. u.
TRV peak value 1600 kV
Minimum arcing time 10,3 ms
T10 (April 2008)
First pole to clear factor 1,5 p. u.
TRV peak value 2062 kV
Minimum arcing time 5,1 ms

12. UHV - Circuit-Breaker 1200 kV Testing: Dielectric performance
8DR1-P kV – 50 kA Prototype
Test at FGH, Manheim , July / August 2008
Withstand voltage tests
Lightning impulse voltage - phase to earth kV
- across open cb kV
Switching impulse voltage - phase to earth kV
- across open cb kV
Power-frequency voltage - phase to earth kV
- across open cb kV

13. 1200 kV AC Current Transformers Solutions: SF6 – Free-standing or Ring-core CB-solution
Main parameters
Rated voltage kV
Rated current 5000 A
Lightning impulse voltage 2400 kV
Switching impulse voltage 1800 kV
Power-frequency voltage 1215 kV
Composite insulators
Creeping distance 25 mm/kV
Overall height 11,3 m
Weight kg
Current
Transformer
Ring-core CB-solution

14. 1200 kV AC Capacitive Voltage Transformer Requirements and Technical Data
Main parameters
Rated voltage kV
Rated current 5000 A
Lightning impulse voltage 2400 kV Switching impulse voltage 1800 kV
Power-frequency voltage 1200 kV
Capacitance 2000 pF
Creeping distance mm/kV
Overall height 11,6 m
Weight 2450 kg
1100kV CVT Prototype running in
Wuhan UHV AC testing base

15. Solutions for 1200 kV AC Substations Conclusions
UHV substations are important node-points in the power supply and distribution with a need of high reliability and high availability.
Standards for the UHV level are under consideration, but not available today.
The switchgear systems and equipment presented here for UHV are tailor made to the customers needs.
A simple copying and scaling up from the system levels below is not always possible for the dimensions and parameters,
but the basic knowledge of technologies and designs can be adapted from the experience with 800 kV DC systems and with 800 kV and 1100 kV AC systems.

16. Thank you, for your attention International UHV Symposium New Delhi, 29. January 2009

17. Circuit Configurations
Arrangement is simple and clear
Acceptable costs
Busbar maintance with shut down of the feeders
Unrestricted and non-stop operation of all feeders in 2 groups
2 BB – Double Busbar Configuration

18. Circuit Configurations
Circuit scheme and arrangement not clear
Expensive design
High availability
Selective Fault clearing with interuption of operation, if both busbars under operation
1 ½ Breaker Configuration

19. Circuit Configurations
Expensive design
High availability
Selective Fault clearing with interuption of operation
2 Breaker Configuration

20. 1200 kV Circuit Configurations Comparison
2 Breaker Configuration
1 ½ Breaker Configuration
Double Busbar Configuration
Arrangement
Clear arrangement
High space requirement because of double number of CB and DS
Arrangement not so clear
Higher space requirement due to 3rd CB per 2 feeder
Arrangement is simple and clear
Acceptable space requirement
Operation
Highest availability
Uninterrupted supply by failing of 1 busbar
Uninterrupted supply during CB maintenance
High availability for radial circuit, only few meshes
Uninterrupted supply by failing of 1 busbar
High availability and flexibility for meshed networks
Uninterrupted supply by failing of 1 busbar with coupler bay
Interrupted power supply during maintenance of CB
Cost
Expensive design
Redundancy of CB and related DS per bay
Additional CB per diameter
Busbar current = bay current
Acceptable costs