HVDC PLUS HVDC PLUS HVDC PLUS −−−Technology, Technology, Technology, BenefitsBenefitsBenefits, , , ApplicationsApplicationsApplicationsPower Transmission and Distribution
London, 4th October 2007J. Dorn; [email protected]
The Smart WayHVDC PLUS – One Step Ahead
2 04.10.2007 Power Transmission and DistributionJ. Dorn, PTD H 1T6
HVDC Classic – HVDC PLUS
~=
=~
AC Grid 1
DC
HVDC Classic HVDC PLUS
Line-commutated current-sourced converter
Self-commutated voltage-sourced converter (VSC)
Thyristors with turn-on capability only
Semiconductor switches with turn-on and turn-off capability, e.g. IGBTs
AC Grid 2
3 04.10.2007 Power Transmission and DistributionJ. Dorn, PTD H 1T6
HVDC Classic – HVDC PLUS
~=
=~
AC Grid 1
DC
HVDC Classic HVDC PLUS
AC Grid 2
C
A
G
G
E
C
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General Features of VSC Technology
Grid access of weak AC networks
High dynamic performance
Independent control of active and reactive power
Supply of passive networks and black start capability
Small space requirements
Additional Features and Benefits of HVDC PLUS
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VSC Technology – A look back
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VSC Technology – A look back
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VSC Technology – A look back
)
+Ud/2
-Ud/2
High harmonic distortion
High transient stresses resulting in HF noise
Desired voltage Realized voltage
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The Multilevel Approach
Small voltage steps
Small steepness of steps
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Modular Multilevel Converter - MMC
Low generation of harmonics
Low HF noise
Low switching losses
Uc
Uc
Uc
0
0
0
Uc
0
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HVDC PLUS with MMC
Phase Unit
Modular Multilevel Converter
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HVDC PLUS with MMC
Modular Multilevel Converter
Phase Unit
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HVDC PLUS with MMC
Phase UnitSubmodule (SM)
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States of Submodules
State 1 = (0,0) State 2 = (1,0) State 3 = (0,1)
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Perfect Voltage Generation
AC and DC voltages controlled by converter leg voltages:
+Ud/2
-Ud/2
Uac
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PLOTS : Graphs
1.000 1.010 1.020
-250 -200 -150 -100 -50
0 50
100 150 200 250
U [k
V]
+Ud -Ud US1 US2 US3
-2.00
-1.50
-1.00
-0.50
0.00
0.50
1.00
1.50
2.00
I [kA
]
is1 is2 is3
-1.50
-1.25
-1.00
-0.75
-0.50
-0.25
0.00
0.25
0.50
0.75
I [kA
]
i1p i2p i3p i1n i2n i3n
Simulation Results: 400 MW with about 200 Submodules per Converter Leg
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Submodule Design
Phase UnitSubmodule
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Submodule Design
Phase UnitSubmodule
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Submodule Design
Phase UnitSubmodule
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Voltage Balancing
Phase UnitSubmodule
PLUSCONTROL
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Converter Reactors
Phase Unit
Parallel connection of three voltage sources
Damp balancing currents between different phases
Limit current gradient during severe faults
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Line-to-Line DC Fault
Phase UnitSubmodule
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Line-to-Line DC Fault
Phase UnitSubmodule
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Modular Design: Submodule
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Pre-Assembled Subunit
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Converter Leg with more than 200 Submodules
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Typical Converter Arrangement for 400 MW
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Optional Seismic Reinforcements
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Main Tasks of PLUSCONTROL TM
Calculation of required converter leg voltages
Choice of submodules to be switched
Control of active and reactive power
Submodule voltage balancing control
1
2
n
SIMATIC TDCC&P System
SIMATIC TDCMeasuring System
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MeasuringSystem 2
MeasuringSystem 1
Uz1P, Uz1N, Uz2P, Uz2N, Uz3P, Uz3N
Converter Control& Protection
System 2
Converter Control& Protection
System 1
1
1
N1P, N2P, N3P, N1N, N2N, N3N
TDM Bus 1TDM Bus 1TDM Bus 1TDM Bus 1
MMS
Current ControlSystem 1&2
6
6
TDM Bus 2TDM Bus 2
IdOrder, IqOrder,A1P, A2P, A3P, A1N, A2N, A3N
C&P Topology – Low Power Range
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TDM
Bus
2TD
M B
us 3
TDM
Bus
2TD
M B
us 3
TDM
Bus
2TD
MBu
s 3
TDM
Bus
2TD
MBu
s 3
TDM
Bus
2TD
MB
us 3
TDM
Bus
2TD
MB
us 3
TDM
Bus
2TD
MB
us 3
TDM
Bus
2TD
MB
us 3
TDM
Bus
2TD
MBu
s 3
TDM
Bus
2TD
MBu
s 3
TDM
Bus
2TD
MBu
s 3
TDM
Bus
2TD
MBu
s 3
C&P Topology – High Power Range
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Main Features of PLUSCONTROL TM
Standard 19 inch racks
Highest degree of modularity
Advanced redundancy concept
Hot plug capability of PCBs and fans
High submodule interfacing capability
High numerical and logical perfomance
Highly flexible
andhighly
reliable control system
Integration into proven SIMATIC TDC systems
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Properties of MMC topology and benefits
High modularity in hardware and software
Low generation of harmonics
Low semiconductor switching frequency
Use of well-proven standard components
Sinus shaped AC voltage waveforms
Easy scalability
Reduced number of primary components
Low rates of rise of current even during faults
High flexibility, economical from low to high power ratings
Only small or even no filters required
Low converter losses
High availability of state-of-the-art components Use of standard AC
transformersLow engineering efforts,
power range up to 1000MWHigh reliability,
low maintenance requirements
Robust system
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Station Layout
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VSC Systems with HVDC PLUS
DC cable transmission (XLPE cable)
DC overhead line transmission
Back-to-Back systems
Multi-terminal systems
STATCOM operation
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Applications of HVDC PLUS
HVDC Systems up to 1000 MW where line-commutated converter have been used in the past
HVDC operation at very weak grids feasible
Grid access for regenerative energy sources, like wind farms
Supply of passive loads
Power supply of megacities
Co
ntrib
utio
n to
redu
ction
in C
O2
emissio
n
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1
12
1
12
1
12
1
12
1
12
1
12
1
12
1
12
1
12
1
12
1
12
1
12
Converter Tower
System Test
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System Test Transformers
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Siemens will beMarket-Leader in VSC-based
HVDC Technology!
Thank you very much for your attention.