HVDC Network as Infrastructure for Smart
SAARC Power Grid
Netra Gyawali, PhD
(Associate Professor)
IOE, Pulchowk Campus, TU
1
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
2
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
3
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
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
5
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
6
KEY HVDC ATTRIBUTES
7
KEY HVDC ATTRIBUTES
Source: IEEE Magazine 2008
KEY HVDC ATTRIBUTES
HVDC TRANSMISSION: CONCEPT
Source: IEEE Magazine 2008
HVDC CONFIGURATIONS
HVDC TRANSMISSION: CONCEPT
Natural Commutation
Based HVDC
• Thyristor or mercury-arc
valves
• Reactive power source
needed
• Large harmonic filters
needed
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
HVDC TRANSMISSION: CONFIGURATION
Source: IEEE Magazine 2008
Source: VG Rao 2005
NORMAL POWER DIRECTION
Source: VG Rao 2005
REVERSE POWER OPERATION
HVDC TRANSMISSION: WORKING
HVDC TRANSMISSION: WORKING
OVERVIEW OF HVDC APPLICATIONS
20
HVDC TRANSMISSION: WORLD PICTURE
21
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)
±450 kV
DC Voltage
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
23
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
24
BRAZIL ARGENTINA HVDC LINE
25
HVDC TRANSMISSION PHILIPPINES
26
HVDC TRANSMISSION: SOME EXAMPLES
27
HVDC Network in SAARC
(BTB Link)
NR
ER
ER
HVDC LINK
CONNECTING
REGION
CAPACITY
Vindyachal
North – West
2 x 250
Chandrapur
West – South
2 x 500
Vizag – I
East – South
500
Sasaram
East – North
500
SR
SR
Source power grid India
(MW)
HVDC LINKS IN SAARC
(INDIA)
29
HVDC IN INDIA BIPOLAR
HVDC LINK
CONNECTING
REGION
CAPACITY
(MW)
LINE
LENGTH
Rihand – Dadri
North-North
1500
815
Chandrapur Padghe
West - West
1500
752
Talcher – Kolar
East – South
2500
1367
Source power grid India
SAARC HVDC LINK:
POSSIBILITIES






India-Pakistan
Nepal-India
Srilanka-India
Bangladesh-India
Bhutan-India
Afghan-Pakistan 31
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.
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
Thank you for your Attention
34