1. (Associate Professor)
HVDC Network as Infrastructure for Smart SAARC Power Grid
Netra Gyawali, PhD
(Associate Professor)
IOE, Pulchowk Campus, TU

2. Contents
Background
Key Attributes of High Voltage Direct Current (HVDC) Transmission
HVDC Transmission: Configuration and Modalities
HVDC Transmission: World Picture
HVDC Transmission: SAARC Context
HVDC Network in SAARC: Possibilities
Conclusions

3. Background Requirement of Modern Transmission GRID
Effective ( Functions as desired)
Speed and accuracy
Efficient (Low Loss)
Asset Management (Optimum use the asset)
Resilience
Interoperability
Accommodate Large Scale Renewable Power

4. Key HVDC Attributes No reactive losses Provision for high cable length
Lower electrical losses
Accommodate Renewable Power
BTB connection
Better Voltage Ride through Capability
The Power Flow on an HVDC link is Fully Controllable (Fast and Accurate)
The operator or automatic controller determines how much power flows via the link and in which direction Irrespective of the interconnected AC system conditions
Connecting different frequencies. E.g. Japan and Brasil: 50Hz grid connected to 60Hz grid by back-to-back (BTB) HVDC.
Connecting two non-synchronous networks. E.g. UCTE and the Russian grid, France and UK
Losses: R*I², but I is lower because no Q

5. Key HVDC Attributes An HVDC Link is asynchronous
The ac voltage and frequency in the two ac networks can be controlled independently of each other
No need for common frequency control
The HVDC link can be used to improve the dynamic conditions in both of the interconnected ac networks (power system damping)
Can be controlled independently of AC system variations
HVDC links do not increase the Short Circuit Level of the connected systems
Faults and oscillations don’t transfer across HVDC interconnected systems
Firewall against cascading outages

6. Key HVDC Attributes
HVDC can transport energy economically and efficiently over longer distances than ac lines or cables
Increased Transmission Capacity in a fixed corridor Up to 3 times more power per tower, therefore narrower rights of way

7. Key HVDC Attributes

8. Key HVDC Attributes
Source: IEEE Magazine 2008

9. Key HVDC Attributes

10. HVDC Transmission: Concept
Source: IEEE Magazine 2008

11. HVDC Configurations

12. HVDC Transmission: Concept
Natural Commutation Based HVDC
Thyristor or mercury-arc valves
Reactive power source needed
Large harmonic filters needed

13. HVDC Transmission: Concept
VSC Based HVDC
Natural Commutation Based HVDC
IGBT valves
P and Q (or U) control
Can feed in passive networks
Smaller footprint
Less filters needed

14. HVDC Transmission: Configuration
Source: IEEE Magazine 2008

15. Decrease voltage at station B or increase voltage at station A
Decrease voltage at station B or increase voltage at station A. power flows from A B Normal direction
Source: VG Rao 2005

16. NORMAL POWER DIRECTION
Source: VG Rao 2005

17. REVERSE POWER OPERATION

18. HVDC Transmission: Working

19. HVDC Transmission: Working

20. Overview of HVDC applications

21. HVDC Transmission: World Picture

22. HVDC Transmission: Some Examples
Norway Netherland Line
Type
submarine cable
Type of current
HVDC
Total length
580 km (360 mi)
Power rating
700 MW
AC Voltage
300 kV (Feda), 400 kV (Eemshaven)
DC Voltage
±450 kV
700 MW
LanguageCode=en&DocumentPartID=&Action=Launch

23. HVDC Transmission: Some Examples
The first HVDC Light transmission
Commissioning year:
1997 (Sweden)
Power rating:
3 MW
No. of poles: 1
AC voltage:
10 kV (both ends)
DC voltage:
±10 kV
Length of DC overhead line:
10 km
Main reason for choosing HVDC Light:
Test transmission

24. VSC HVDC example: troll (north sea)
HVDC Transmission: Some Examples
VSC HVDC example: troll (north sea)
Commissioning year: 2005
Power rating: 2 x 42 MW AC Voltage:132 kV at Kollsnes, 56 kV at Troll
DC Voltage: +/- 60 kV
DC Current: 350 A
Length of DC cable:4 x 70 km
Main reason for choosing HVDC Light:
Environment, long submarine cable distance, compactness of converter on platform

25. Brazil Argentina HVDC line

26. HVDC Transmission Philippines

27. HVDC Transmission: Some Examples

28. HVDC Network in SAARC (BTB Link) NR ER ER SR SR HVDC LINK
CONNECTING REGION
CAPACITY
(MW)
Vindyachal
North – West
2 x 250
Chandrapur
West – South
2 x 500
Vizag – I
East – South
500
Sasaram
East – North SR SR
Source power grid India

29. HVDC LINKS IN SAARC (India)

30. HVDC IN INDIA Bipolar HVDC LINK CONNECTING REGION CAPACITY (MW)
LINE LENGTH
Rihand – Dadri
North-North
1500
815
Chandrapur - Padghe
West - West
752
Talcher – Kolar
East – South
2500
1367
Source power grid India

31. SAARC HVDC Link: Possibilities
India-Pakistan
Nepal-India
Srilanka-India
Bangladesh-India
Bhutan-India
Afghan-Pakistan

32. Conclusions
HVDC transmission has number of benefits for bulk power transmission; namely efficiency, resilience, interoperability etc.
In short distance, BTB HVDC provides smart link for frequency conversion and renewable power integration.
In SAARC Country, the development of HVDC is only limited to India. For cross-border transmission link, HVDC is a good candidate.
Combining with FACTS technology, HVDC provides a infrastructure of the future Smart Transmission Grid for SAARC.

33. References
Understanding Facts: Concepts and Technology of Flexible AC Transmission Systems, Narain G. Hingorani, Laszlo Gyugyi
Flexible AC transmission systems, Song & Johns
Thyristor-based FACTS controllers for electrical transmission systems, Mathur Vama

34. Thank you for your Attention