the challenges facing hvdc in the early 21st century
TRANSCRIPT
The Challenges facing HVDC inthe Early 21st Century
Dr Norman MacLeodTechnical Director, HVDC
Visiting Professor, Leeds University
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Contents
• HVDC – a very brief history• Development of ±800kV equipment• Development of VSC-HVDC solutions• New challenges
• 1100kV transmission• High altitude stations/lines• Building the DC Super Grid• Building the Smart Grid
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HVDC Scheme/Technology Progression
0
5
10
15
20
25
30
Y/E 55 Y/E 60 Y/E 65 Y/E 70 Y/E 75 Y/E 80 Y/E 85 Y/E 90 Y/E 95 Y/E 00 Y/E 05 Y/E 10 Y/E 15
IGBT
Thy
Merc
Number of schemes per 5 year interval
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Power/Voltage Progression
0
1000
2000
3000
4000
5000
6000
7000
8000
0 100 200 300 400 500 600 700 800 900
Pow
er(M
W)
DC Voltage (kV)
Contents
• HVDC – a very brief history• Development of ±800kV equipment• Development of VSC-HVDC solutions• New challenges
• 1100kV transmission• High altitude stations/lines• Building the DC Super Grid• Building the Smart Grid
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500kV Thyristor ValvesSource : Alstom
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660kV Thyristor ValveSource : Alstom
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600kV Converter TransformerSource : Alstom
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Air Breakdown TestingSource : Alstom
Switching impulsevoltage tests on thyristorvalve test object – VITLaboratory in Ukraine
• Test voltages up to2200kV• Clearance to wall/floorup to 9m
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Switching Impulse TestsSource : Alstom
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Switching Impulse TestSource : Alstom
Voltage = 2200kV
Clearance = 9m to wall
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Long Arc PhysicsSource : Alstom
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Long Arc PhysicsSource : Alstom
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Long Arc PhysicsSource : Alstom
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Long Arc PhysicsSource : Alstom
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UHV Switching Impulse TestingSource : ABB
Rod – plane air gap Sphere – plane air gap
“Intriguing observation on the breakdown trajectory of large air gaps under switchingimpulse voltages”, L Ming, D Wu. U Astrom and G Asplund, 16th International Symposium onHigh Voltage Engineering, Cape Town, South Africa, 2009
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800kV DisonnectorSource : Siemens
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800kV DC Current TransducerSource : Alstom
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±800kV Transmission lineSource : SGCC
Contents
• HVDC – a very brief history• Development of ±800kV equipment• Development of VSC-HVDC solutions• New challenges
• 1100kV transmission• High altitude stations/lines• Building the DC Super Grid• Building the Smart Grid
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VSC HVDC - Principle
Steady DCVoltage
Input
+
Alternating Voltage Output
VSC
By controlling the phase angle and magnitude of the output voltage,the VSC converter can control real power and reactive power flowinto the AC system. It looks like a “generator” or “load”
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VSC – HVDC StationSource : ABB
Contents
• HVDC – a very brief history• Development of ±800kV equipment• Development of VSC-HVDC solutions• New challenges
• 1100kV transmission• High altitude stations/lines• Building the DC Super Grid• Building the Smart Grid
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1100kV DC Wall BushingSource : Alstom
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Altitude Effects
Atmospheric pressure correctionimpacts on insulation clearances.
From IEC 60071 – 2, section 4.2Correction factor Ka = em(H/8150),where
H = altitude (m)m =1.0 for lightning impulsem < 1.0 for switching impulse 0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
0 1000 2000 3000 4000Ka
Altitude (m)
m = 1.0
m = 0.5
High Altitude
• HVDC schemes at elevated altitude• China - >4000m (Tibetan plateau)• USA - >12,000ft (Rocky Mountains)
• China has a high altitude testing station in Tibet
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Off-shore Wind Farm
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Multiple Off-shore Wind Farms
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Off-shore DC Grid
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DC Super GridSource : FOSG
The Super Grid - Questions
• How do we achieve “standardisation” of solutions?• Can we develop a DC/DC “transformer”?• How do we ensure “interoperability” between multiple
vendors equipment?• How do we control the power flows between nodes?• What and how do we communicate from dispatch to the
nodes?• How do we protect the Super grid?• Can we develop a DC circuit breaker – at reasonable cost?
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The Existing AC grid
ACAC
132 kV 132 kV
400 V 400 V
11 kV
400 kV
400 V
11 kV
11 kV
AC
AC
AC
AC
AC
AC
AC
AC
AC
ACAC
AC
AC
AC
AC
AC
The AC/DC Grid of Tomorrow?
ACAC
DCDC
132 kV 132 kV
400 V 400 V
11 kV
400 kV
400 V
11 kV
11 kV
Offshorewind farm
150 kV 150 kV 150 kV150 kV
Bulk power import using UHVDC
600 kV
ACDC
DC
DC
AC
DC
AC
DC
50 kV 50 kV
DC
DC
DC
DC
AC
AC
AC
AC
AC
AC
AC
ACAC
AC
AC
AC
AC
AC
AC
DC
DC
DC
DC
DC
DC
DC
DC
DC500 V
Electric VehicleCharging Stationstation
AC
DC
AC
AC
10 kV 10 kV
AC
DC
AC
AC
500 V
BatteryEnergyStorageSystem
PhotoVoltaic
DC
DC
PowerCells
The Smart Grid - Questions
• Can we develop MVDC technology at reasonable cost?• Can we integrate different power electronic technologies?
• AC – DC converters• DC – DC converters• STATCOM• Wind turbines• Inverters from PV, EV, BESS, etc
• Can we integrate Automation solutions (EMS, WAM, PMU)with Power Electronic solutions?
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Conclusions
• Even after 60 years of HVDC technology advancement thereare still many challenges ahead.
• The challenges can be solved, but we need Engineers.
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Thank you for your attentionAny Questions?
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