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Operation and Control of an HVDC Circuit Breaker
with Current Flow Control Capability
ESR3: Wei Liu
Supervisors:Jun Liang & Carlos Ugalde Loo
Cardiff University, UK @ October 2020
This project has received funding from the European Union's Horizon 2020 research and innovationprogramme under the Marie Sklodowska-Curie grant agreement no. 765585. This presentation reflects onlythe author’s view. The Research Executive Agency and European Commission are not responsible for anyuse that may be made of the information it contains.
Outline
1. Motivations
2. Proposed device
3. Simulation results
4. Conclusion
1
1. Motivations
2
Multi-terminal DC systems
3
Multi-terminal HVDC systems
Improve system’s flexibility Improve system’s reliability Integrate different types of renewable energy
‘Zhangbei’ ± 500 kV HVDC system for Beijing Olympic Games 2022
[1] G. Tang, H. Pang, Z. He and X. Wei, "Research on Key Technology and Equipment for Zhangbei 500kV DC Grid," in Proc. 2018 International Power Electronics Conference Niigata, 2018, pp. 2343-2351.
CBCFC
T1 T2
T3T4
L12
L23
L34
L14
CBCFC
Parallel paths
MTDC networks
DC fault and Current flow control
4
Challenges of MTDC grids: dc fault
No zero crossings (dc current) High rising rate of current (di/dt) Low capability of overcurrent (IGBTs)
Examples of dc fault for VSC
Challenges of MTDC grids: Current flow control
Dominated by the resistance of the transmission lines Overloading of transmission lines Limit capacity of power transmission
CBCFC
T1 T2
T3T4
L12L
23
L34
L14
CBCFC
Parallel paths
Four-terminal system
Challenges
5
500 kV HCB developed for Zhangbei project
Challenges for DCCB and CFC
Cost Reliability
M. Callavik, A. Blomberg, J. Hafner, and B. Jacobson, “The hybrid HVDC breaker: an innovation breakthrough enabling reliable HVDC grids”, ABB Grid Systems, Technical Paper, Nov. 2012.
‘Zhangbei’ ± 500 kV HVDC system for Beijing Olympic Games 2022
Solutions
6
M. Callavik, A. Blomberg, J. Hafner, and B. Jacobson, “The hybrid HVDC breaker: an innovation breakthrough enabling reliable HVDC grids”, ABB Grid Systems, Technical Paper, Nov. 2012.
CFC
L12
L13
L1
CB
CB
CB
MMC
(a)
CB/
CFC
(b)
L12
L13
L1
CB
MMC
Targets
Integrate several CBs and CFC into one device Reduce semiconductors and costs Maintain same function
Separate HCBs and CFC. Integrated device.
2. Proposed device
7
Proposed device
8
Topologies
Two CBs and one CFC integrated
MO
V1 U1p
U1n U2n U3n
U2p U3p
S1p
S1n
S2p
S2n
S3p
S3n
MBL1 L2 L3
MO
Vn
Main breaker branch Low-loss branches Capacitor branch
Uc
Sc
Proposed device (CB/CFC)
CB/
CFC
I1 I12
I13
I23
I2
I3
Node 2
Node 3
Node 1
MMC1
Circuit BreakerCurrent limit inductor Transmission Line
MMC2
MMC3
L12
L13
L23
System configuration with the CB/CFC
Proposed device
9
DC fault isolating
Four steps
(a) (b)
(c) (d)
MO
V1U1p
U1n U2n U3n
U2p U3p
S1p
S1n
S2p
S2n
S3p
S3n
MBL1 L12 L13
MO
Vn
Uc
Sc
Vc
MO
V1U1p
U1n U2n U3n
U2p U3p
S1p
S1n
S2p
S2n
S3p
S3n
MBL1 L12 L13
MO
Vn
Uc
Sc
Vc
MO
V1U1p
U1n U2n U3n
U2p U3p
S1p
S1n
S2p
S2n
S3p
S3n
MBL1 L12 L13
MO
Vn
Uc
Sc
Vc
MO
V1U1p
U1n U2n U3n
U2p U3p
S1p
S1n
S2p
S2n
S3p
S3n
MBL1 L12 L13
MO
Vn
Uc
Sc
Vc
Fault isolation process. (a) Pre-fault. (b) Current commutation. (c) Fault current interruption. (d) Post fault.
Proposed device
10
MO
V1 U1p
U1n U2n U3n
U2p U3p
S1p
S1n
S2p
S2n
S3p
S3n
MBL1 L2 L3
MO
Vn
Main breaker branch Low-loss branches Capacitor branch
Uc
Sc
Current flow control
Vc
S1p
S1n
S2p
S2n
S3p
S3n
L1
L12
L13
Simplified equivalent circuit as a CFCTopology of CB/CFC
Proposed device
11
Bypass mode
Vc
S1p
S1n
S2p
S2n S3n
S3p I12
I13=0
Vc I13=0
I12I1
Current nulling mode
Vc
S1p
S1n
S2p
S2n S3n
S3pI1
I13
I12I1 Vc=0
I13
I12
Vc
S1p
S1n
S2p
S2n S3n
S3pI1
PWM
DVc
(1-D)Vc
I13
I12I1
I13
I12
Vc
S1p
S1n
S2p
S2n S3n
S3pI1
PWM
(1-D)Vc
DVc
I13
I12I1
12 1I I D=12 1 /I I D=1 12 13I I I= + 12 1 13, 0I I I= =
Current sharing mode
Proposed device
12
Control and modulations
0
-1
1
2
-2Iref
vcref>0
Carrier (500Hz)
(a)
vcref<0
PWM_12
PWM_1p
PWM_1n
PWM_13
Gate SignalsComparators
Signvcref
Vc
S1p
S1n
S2p
S2n
S3p
S3n
L12
L13
I1
MMC1
PIPI
vc
i12
×
vcref
Sign
Modulation
S1pS1n
S2p
S2n
S3p
S3n
Dual-loop control for the CFC
C1
C2
C3
C4
(b)Modulation
Sharing
Reverse
Reverse
Level-shift modulation Dual-loop control loop
3. Simulation results
13
Proposed device
14
System parameters
CB/
CFC
I1 I12
I13
I23
I2
I3
Node 2
Node 3
Node 1
MMC1
Circuit BreakerCurrent limit inductor Transmission Line
MMC2
MMC3
L12
L13
L23
Proposed device
15
Simulation results of dc fault isolation
CB/
CFC L12
L13
L1CB
MMC
CB/
CFC L12
L13
L1CB
MMC
Protection of dc faults at transmission lines. (a) Fault current. (b) Currents of MB and MOV. (c) Voltage of MB. (d) Energy absorbed by the CB/CFC.
Protection of dc faults at transmission lines. (a) Fault current. (b) Currents of MB and MOV. (c) Voltage of MB. (d) Energy absorbed by the CB/CFC.
Proposed device
16
Simulation results of current flow control
Current reversal mode for CFC operation. (a) Active power ofconverters. (b) DC currents of converters. (c) Currents oftransmission lines. (d) Modulation and carrier signals.
Current reversal mode for CFC operation. (a) Active power ofconverters. (b) DC currents of converters. (c) Currents oftransmission lines. (d) Modulation and carrier signals.
Proposed device
17
Comparisons
(a)
(b)
(c)
CFCHCB1HCB2
HCB3
HCB1
HCB1
CFC
CB/CFC
HCB2&3
U1
U2
U1
U2
U1
U4
U7
U6
U3
U2
U5
MB(n)
MB(n) MB(n)
MB(n)
MB (n)
L12L13
L12L13
L1
L1
MMC1
MMC1
MMC1
L12L13
U0
U0
U0
MB
L1
MB
MB
MB (n)
MB (n) MB (n)
Integrated schemes of CFC with HCB. (a) Scheme I: Sharing LCSs.(b)Scheme II: Sharing LCSs and MBs. (c) Scheme III: CB/CFC.
4. Conclusion
18
Conclusion
19
1. DC protection and current flow control were analysed for MTDC applications
2. The proposed device was described.
3. Simulation results were given to verify the function of the proposed device.
[1] Wei Liu, Jun Liang, Carlos Ugalde Loo, Chuanyue Li, Gen Li, Peng Yang. “Level-shift Modulation and Control of a Dual H-bridge Current Flow Controller in Meshed HVDC systems”. ECCE.2019.
[2] Wei Liu, Carlos Ugalde Loo, Jun Liang, Chuanyue Li, Frederic. “Modeling and Frequency Analysis of a Dual H-bridge Current Flow Controller in Meshed HVDC Systems”. EPE.2019.
[3] W. Liu, C. Li, C. E. Ugalde-Loo, S. Wang, G. Li and J. Liang, “Operation and Control of an HVDC Circuit Breaker with Current Flow Control Capability," IEEE Journal of Emerging and Selected Topics in Power Electronics (Early access).
[4] S. Wang, W. Ming, W. Liu, C. Li, C. E. Ugalde Loo and J. Liang, "A Multi-Function Integrated Circuit Breaker for DC Grid Applications," IEEE Transactions on Power Delivery (Early access).
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