Post on 28-Apr-2018
transcript
Multilevel STATCOMs – a new converter topology that opens up the market
Simon Sinsel, Siemens AG, Germany
Ian Ramsay, Siemens Inc., NC, USA
Key Messages
• We describe three multilevel STATCOM installations in Chile, Australia and the US.
• Each multilevel STATCOM fulfills a different primary electrical performance requirement – dynamic voltage support, load balancing and flicker reduction.
• Secondary features of the multilevel STATCOM technology favor its application on these projects – modularity, low interaction with the network in terms of harmonics and the low amount of primary equipment.
Source: Siemens AG
Agenda
Multilevel STATCOM Topology Overview
Case 1: Reactive Power Support for Increased Transmission Capacity
Case 2: Dynamic Load Balancing for Railway Applications
Case 3: Flicker Reduction
Conclusion
Multilevel STATCOM Topology Overview
Modul #1
Modul #2
Modul #3
Modul #4
Modul #n
Modul #n-1
Modul #n-2
Modul #n-3
Terminal A Terminal B
• Multilevel STATCOM is built by Power Modules connected in series. The required
output determines the number of modules.
• The sum of all power module output voltages form the terminal voltage.
• The reactive power output is controlled via the amplitude of the converter voltage.
Source: Siemens AG
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Reactive Power Support for Increased Transmission Capacity Diego de Almagro, Chile
Taltal
Carrera
Pinto
Diego de Almagro
SVC PLUSCardones
Maitencillo
Initial situation
• Trip on one of three Cardones – Maitencillo circuits led to voltage instability in northern transmission region.
• Dynamic voltage recovery criteria could only be fulfilled by limiting load on Cardones – Maitencillo lines to 340 MW.
• Increased power demand and relatively high generation cost in northern region provided incentive to increase transmission capacity on the corridor.
Grid schematic with installed multilevel STATCOM; Source: TRANSELEC
Reactive Power Support for Increased Transmission Capacity Diego de Almagro, Chile
Taltal
Carrera
Pinto
Diego de Almagro
SVC PLUSCardones
Maitencillo
Primary Project Requirement
• Increase of reactive power supply in the northern region to
(1) comply with grid code and
(2) increase load limitation from the southern grid region.
Additional Project Requirements
• Design, supply and commissioning within 15 months.
• Increased level of redundancy beneficial.
Grid schematic with installed multilevel STATCOM; Source: TRANSELEC
Reactive Power Support for Increased Transmission Capacity Diego de Almagro, Chile
220 kV
14 kV
±50 Mvar
100 MVA
±50 Mvar +40 Mvar
Results
• Compliance to required grid code criteria.
• Increased level of redundancy due to twin configuration.
• Installation increased transmission capacity through Cardones – Maitencillo from 340 to 420 MW.
SLD of installed multilevel STATCOM; Source: Siemens AG
-0.5-1.0 0.5 Iprim [pu]
Vprim [pu]
capacitive inductive
0.5
1.0
1.0
continuous operation
Multilevel STATCOM
time limited operation
Multilevel STATCOM
continuous operation
conventional SVC
time limited operation
conventional SVC
Source: Siemens AG
Reactive Power Support for Increased Transmission Capacity Diego de Almagro, Chile
Multilevel STATCOM installation at Diego de Almagro Substation; Source: Siemens AG
Dynamic Load Balancing for Railway Applications Wycarbah, Duaringa & Bluff, Australia
Initial situation
• Projected substantial increase of coal export via railway from Central Queensland to coast for export.
• Increased use of induction motor locomotives instead of DC and diesel-electric locomotives.
• Due to both drivers, potential non-compliance to grid code limitations for positive and negative sequence voltage.
FS FSTrSC
SVC SVCSVC
Railway electrification scheme prior to upgrade Source: Powerlink Queensland
Dynamic Load Balancing for Railway Applications Wycarbah, Duaringa & Bluff, Australia
Primary Project Requirement
• Installation of additional parallel compensation devices at three sites.
Additional Project Requirements
• Low interaction with the grid in terms of harmonics.
• Electrical similarity between all three sites beneficial.
132 kV Feeder
30/40 MVA
132/50 kV
±100 Mvar
Feeder
Catenary
Auto
Transformers
100 MVA
132/30 kV
Filter Filter
Tx2Tx1
Schematic feeder station with installed multilevel STATCOM Source: Powerlink Queensland
Dynamic Load Balancing for Railway Applications Wycarbah, Duaringa & Bluff, Australia
00 A
20 A
40 A
60 A
80 A
100 A
120 A
140 A
160 A
00
:00
:01
00
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:41
01
:27
:21
02
:11
:01
02
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:41
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:21
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:05
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:49
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:33
:01
07
:16
:41
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:00
:21
08
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:01
09
:27
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10
:11
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10
:55
:01
11
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:06
:01
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:21
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:01
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:00
:41
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:01
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:11
:41
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:55
:21
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:39
:01
20
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:41
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:06
:21
21
:50
:01
22
:33
:41
23
:17
:21
Tx 1
Tx 2
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.40
00
:00
:01
00
:42
:31
01
:25
:01
02
:07
:31
02
:50
:01
03
:32
:31
04
:15
:01
04
:57
:31
05
:40
:01
06
:22
:31
07
:05
:01
07
:47
:31
08
:30
:01
09
:12
:31
09
:55
:01
10
:37
:31
11
:20
:01
12
:02
:31
12
:45
:01
13
:27
:31
14
:10
:01
14
:52
:31
15
:35
:01
16
:17
:31
17
:00
:01
17
:42
:31
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:25
:01
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:07
:31
19
:50
:01
20
:32
:31
21
:15
:01
21
:57
:31
22
:40
:01
23
:22
:31
NPS (in %)
Results
• Significant reduction of NPS.
• Compliance to required grid code criteria for negative and positive phase sequence and harmonics.
• Synergy potential in project delivery, operation and maintenance due to same configuration.
STATCOM in service
STATCOM out of service
Comparison of NPS with multilevel STATCOM in service and out of service Source: Powerlink Queensland
Dynamic Load Balancing for Railway Applications Wycarbah, Duaringa & Bluff, Australia
Multilevel STATCOM installation at Wycarbah Feeder Station; Source: Siemens AG
Flicker Reduction CMC Steel, TX, USA
15 kV Electric Arc Furnace Busbar
STATCOM
±45 Mvar
STATCOM
±45 MvarFilter Filter
Initial situation
• CMC Steel Texas operates an 80 MVA AC Electric Arc Furnace on a 15 kV busbar.
• Existing STATCOM was not able to reduce the flicker to required value of Pst < 0.8 on the 138 kV PCC.
• Grid code compliance only possible with a flicker reduction factor higher than four.
SLD of multilevel STATCOM directly connected to Arc Furnace Busbar Source: Siemens AG
Flicker Reduction CMC Steel, TX, USA
Results
• Significant reduction of Flicker.
• Flicker performance of multilevel STATCOM higher compared to conventional Thyristor-based SVC (Factor 4 vs. factor 2).
Flicker comparison of 1st generation STATCOM and multilevel STATCOM Source: CMC Steel
Flicker Reduction CMC Steel, TX, USA
Multilevel STATCOM installation at CMC Steel, Tx; Source: CMC Steel
Conclusion
• We described three multilevel STATCOM installations in Chile, Australia and the US.
• Each multilevel STATCOM fulfills a different primary electrical performance requirement – dynamic voltage support, load balancing and flicker reduction.
• Secondary features of the multilevel STATCOM technology favor its application on these projects – modularity, low interaction with the network in terms of harmonics and the low amount of primary equipment.
Source: Siemens AG
Thank You!
For questions, comments & discussions please contact:
Simon Sinsel
simon.sinsel@siemens.com
Siemens AG, Germany
Ian Ramsay
ian.ramsay@siemens.com
Siemens Energy Inc., NC, USA
Source: Siemens AG
References
• V. Hild, L. Kirschner, G. Pilz, L. Peuther and B. Gemmell, "The best of both – Combining STATCOM with conventional thyristor based Static Var Compensator technology", unpublished, presented at the EPRI Conference, Palo Alto, CA, 2013.
• M. Pereira, D. Retzmann, J. Lottes, M. Wiesinger and G. Wong, “SVC PLUS: An MMC STATCOM for Network and Grid Access Applications” presented at IEEE PowerTech, Trondheim, 2011.
• A. Handschick, A.J. Hernandes, F. Schettler, B. Strobl, “Voltage Control in Offshore Wind Farms Using Switched Compensation Elements (MSCs, MSRs) Together with the Reactive Power Capability of the Wind Turbine Generators” unpublished, Erlangen, 2010.
• A. Janke, R. Memisevic and G. Pilz, “Queensland Railways Upgrade Project”, SCB4 Colloquiu, CIGRE, Paris, 2011.