HVDC Network as Infrastructure for Smart SAARC Power Grid

1

Netra Gyawali, PhD(Associate Professor)

IOE, Pulchowk Campus, TU

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

• Effective ( Functions as desired) Speed and accuracy

• Efficient (Low Loss)• Asset Management (Optimum use the asset)• Resilience• Interoperability • Accommodate Large Scale Renewable Power

3

Requirement of Modern Transmission GRID

KEY HVDC ATTRIBUTES

• No reactive lossesProvision for high cable lengthLower 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

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: CONCEPT

HVDC TRANSMISSION: CONFIGURATION

Source: IEEE Magazine 2008

Source: VG Rao 2005

NORMAL POWER DIRECTIONNORMAL POWER DIRECTION

Source: VG Rao 2005

REVERSE POWER OPERATION

HVDC TRANSMISSION: WORKING

HVDC TRANSMISSION: WORKING

OVERVIEW OF HVDC APPLICATIONS

20

21

HVDC TRANSMISSION: WORLD PICTURE

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

HVDC TRANSMISSION: SOME EXAMPLES

Norway Netherland Line

23

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

HVDC TRANSMISSION: SOME EXAMPLES

The first HVDC Light transmission

24

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

HVDC TRANSMISSION: SOME EXAMPLES

BRAZIL ARGENTINA HVDC LINE

25

HVDC TRANSMISSION PHILIPPINES

26

27

HVDC TRANSMISSION: SOME EXAMPLES

HVDC Network in SAARCHVDC Network in SAARC(BTB Link)(BTB Link)

ER

SR

NR

ER

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 500

Source power grid India

29

HVDC LINKS IN SAARC (INDIA)

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

31

SAARC HVDC LINK:POSSIBILITIES

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

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