CIGRE B4 HVDC and Power Electronics

1
CIGRE B4 HVDC and Power Electronics

• Working Group 37
• VSC Transmission
• presented by
• Dr Bjarne R Andersen

2
VSC Transmission

• Presentation Overview
• VSC Transmission technology,
• Comparison of VSC Transmission and LCC HVDC
  technology,
• Application Examples,
• B4-37s vision of the outlook for VSC
  Transmission,
• VSC Transmission, is it FACTS or HVDC
  Transmission with modern devices?

3
The Voltage Sourced Converter

• Semi-conductors capable of turn-on AND turn-off
  are used
• An ac voltage with controllable amplitude and
  phase angle is produced.

4
Four Quadrant Control

• The Reactive Power output depends on the voltage
  amplitude

5
Four Quadrant Control

• The Active Power output depends on the converter
  voltage Phase Angle

6
Four Quadrant Control

• Simplified PQ Diagram

7
VSC - 3 phase implementation

• 3 phase 2-level Voltage Sourced Converter

8
Waveform of 3 phase 2-level VSC
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Controlability

• Full Wave control
• Large Harmonic filters required
• Pulse Width Modulation
• Small Harmonic Filters
• High Speed of Response
• Independence of the converters at each end

10
3-level VSC

• Waveshape shown for Full wave switching

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Pulse Width Modulation
PWM switching at 21 times fundamental frequency
2-Level VSC
3-Level VSC
12
VSC Transmission terminal
Interface transformer
13
Physical Layout, 65 MVA HVDC LightTM Converter
Station
Building 45 x 18 m
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VSC Transmission scheme

• Simplified diagram of VSC Transmission scheme

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VSC Transmission - Main Features

• The VSC valves are self-commutating
• Can operate into a dead ac network.
• No commutation failures
• 4 Quadrant control
• Independent Q control at each end AND independent
  of Real Power flow
• The ac harmonic filters need not be switchable,
  as they are not essential for reactive power
  control
• The voltage polarity on the dc side is always the
  same.
• Enables the use of low cost polymeric cables
• The VSC stations can be operated as STATCOMs,
  even if the VSC is not connected to the dc line

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VSC Transmission

• Presentation Overview
• VSC Transmission technology
• Comparison of VSC Transmission and LCC HVDC
  technology
• Application Examples
• B4-37s vision of the outlook for VSC
  Transmission
• VSC Transmission, is it FACTS or HVDC
  Transmission with modern devices?

17
Comparison - 1
18
Comparison - 2
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Comparison - 3
20
Comparison - 4
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VSC Transmission

• Presentation Overview
• VSC Transmission technology
• Comparison of VSC Transmission and LCC HVDC
  technology
• Application Examples - Courtesy of ABB
• B4-37s vision of the outlook for VSC
  Transmission
• VSC Transmission, is it FACTS or HVDC
  Transmission with modern devices?

22
Gotland - the first commercial HVDC LightTM
project

• Technical Data
• Commissioning year 1999
• Power rating 50 MW
• AC Voltage 70 kV both sides
• DC Voltage 80 kV
• DC current 350 A
• Length of DC cable 2 x 70 km

Main reasons for choosing HVDC system Wind power
(voltage support). Easy to get permission for
underground cables.
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Gotland HVDC Light
Gotland HVDC Light converter station at Näs,
exterior view
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Gotland HVDC Light
Converter station at Näs blends in well with
surrounding farms.
25
Murraylink
Technical Data Commissioning year 2002 Power
rating 200 MW AC Voltage 132/220 kV DC
Voltage 150 kV DC current 739 A Length of
DC cable 2 x 180 km
Main reasons for choosing HVDC system Controlled
asynchronous connection for trading. Easy to get
permission for underground cables.
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Murraylink - valve enclosures
At factory
Inside building
Placed on foundation
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Murraylink
Murraylink, the Berri converter station.
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Eagle Pass

• I would like a couple of slides in a format
  similar to those for Cross Sound, i.e.
• 1 slide with
• Map
• Technical data
• Main reason for choosing HVDC Light
• 2nd slide with
• Site photo
• Your help will be appreciated

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Cross Sound Cable
Technical Data Commissioning year 2002 Power
rating 330 MW AC Voltage 345 kV at New
Haven 138 kV at Shoreham DC Voltage 150 kV DC
current 1175 A Length of DC cable 2 x 40 km
Main reasons for choosing HVDC system Controlled
connection for trading. Submarine cables without
oil.
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The worlds largest HVDC LightTM project
Cross Sound - 346MVA, Shoreham Terminal
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Troll A HVDC LightTM link
The HVDC LightTM installation between the
Norwegian main land and the Troll A oil platform
consists of two circuits, each feeding a 40 MW
compressor motor
Technical Data Commissioning year Planned
2004/2005 Power rating 2 x 42 MW AC Voltage
132 kV/56 kV DC Voltage 60 kV DC current
350 A Length of DC cable 4 x 70 km
Main reasons for choosing HVDC LightTM system
Environmental improvement by elimination of gas
turbines on platform. Low weight and small space
on platform. Ability to feed and black-start
motors, without local generation.
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Troll A HVDC LightTM link
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VSC Transmission

• Presentation Overview
• VSC Transmission technology
• Comparison of VSC Transmission and LCC HVDC
  technology
• Application Examples
• B4-37s vision of the outlook for VSC
  Transmission
• VSC Transmission, is it FACTS or HVDC
  Transmission with modern devices?

34
VSC Transmission Outlook

• VSC Transmission has many technical advantages
  over LCC HVDC
• WG-37 has not identified any technical reason
  why VSC Transmission cannot be developed for very
  high voltage and power, say 500kVdc, 3000MW
• Main drawbacks relative to LCC HVDC are its
  presently higher capital cost at large power and
  its higher power losses.

35
VSC Transmission trends

• Future Developments
• Increased dc voltage (higher power, longer
  distances)
• Increased dc current (higher power)
• New topologies (lower losses)
• New Semi-conductor devices (lower losses and
  cost)
• Resulting in
• VSC Transmission competing head on with LCC HVDC
  in more and more applications.

36
Development Trends in Controllable switches
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VSC Transmission

• Presentation Overview
• VSC Transmission technology
• Comparison of VSC Transmission and LCC HVDC
  technology
• Application Examples
• B4-37s vision of the outlook for VSC
  Transmission
• VSC Transmission, is it FACTS or HVDC
  Transmission with modern devices?

38
FACTS Device?

• FACTS (Flexible AC Transmission Systems) "a power
  electronic based system and other static
  equipment that provide control of one or more ac
  transmission system parameters to enhance
  controllability and increase power transfer
  capability.
• A VSC Transmission scheme can transport power
  within a network, and provide ac voltage control
  at both terminals.

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FACTS Device!

• The ability to provide active power and reactive
  power modulation gives very powerful swing
  damping
• ABB studies have shown that an imbedded VSC
  Transmission scheme can increase the loadability
  of the local ac network by up to 1.5 times the
  MVA rating of the VSC Transmission scheme (CIGRE
  Session 2004, Paper B4-204).

40
VSC Transmission

• Presentation Overview
• VSC Transmission technology,
• Comparison of VSC Transmission and LCC HVDC
  technology,
• Application Examples,
• B4-37s vision of the outlook for VSC
  Transmission,
• VSC Transmission, is it FACTS or HVDC
  Transmission with modern devices?

41
Thank you for your Attention
Andersen Power Electronic Solutions Ltd

• Any Questions?