HVDC Network as Infrastructure for Smart SAARC Power Grid

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• HVDC Network as Infrastructure for Smart SAARC
  Power Grid

Netra Gyawali, PhD (Associate Professor) IOE,
Pulchowk Campus, TU
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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

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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

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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

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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 dont transfer across
  HVDC interconnected systems
• Firewall against cascading outages

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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

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Key HVDC Attributes
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Key HVDC Attributes
Source IEEE Magazine 2008
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Key HVDC Attributes
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HVDC Transmission Concept
Source IEEE Magazine 2008
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HVDC Configurations
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HVDC Transmission Concept

• Natural Commutation Based HVDC
• Thyristor or mercury-arc valves
• Reactive power source needed
• Large harmonic filters needed

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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

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HVDC Transmission Configuration
Source IEEE Magazine 2008
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Source VG Rao 2005
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NORMAL POWER DIRECTION
Source VG Rao 2005
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REVERSE POWER OPERATION
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HVDC Transmission Working
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HVDC Transmission Working
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Overview of HVDC applications
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HVDC Transmission World Picture
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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
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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
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VSC HVDC example troll (north sea)
HVDC Transmission Some Examples

• Commissioning year 2005
• Power rating 2 x 42 MW AC Voltage132 kV at
  Kollsnes, 56 kV at Troll
• DC Voltage /- 60 kV
• DC Current 350 A
• Length of DC cable4 x 70 km

Main reason for choosing HVDC Light Environment, long submarine cable distance, compactness of converter on platform
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Brazil Argentina HVDC line
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HVDC Transmission Philippines
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HVDC Transmission Some Examples
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HVDC Network in SAARC (BTB Link)
NR
ER
ER
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 500

SR
SR
Source power grid India
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HVDC LINKS IN SAARC (India)
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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
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SAARC HVDC Link Possibilities

• India-Pakistan
• Nepal-India
• Srilanka-India
• Bangladesh-India
• Bhutan-India
• Afghan-Pakistan

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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.

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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

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• Thank you for your Attention