Integrating Smart Transformers (SST) Into Distribution Substations - - PowerPoint PPT Presentation
Integrating Smart Transformers (SST) Into Distribution Substations December 2015 by Shaban Awili Cigr SCB1 Page 1 Agenda SST Research Motivation Smart Transformer Technology Overview System Integration Requirement Impact on
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December 2015 by
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SST Research Motivation Smart Transformer Technology Overview System Integration Requirement Impact on Distribution Substation Cost Implications System-oriented analysis summary
Identify (SST) Advantages Understand (SST) Challenges Develop Comparison Framework
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Transmission HV Distribution MV Distribution LV
“Our aim is that by 2027 we will have an active Electricity Network That Maximises Renewables Usage” Said John Byrne
ESB
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Smart Transformer Add Functions Add Benefits
Potential Issues
Consumer Control Add Control
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“It is a box that can take energy in any form – it doesn’t care whether it is AC or DC – and it will provide energy on the secondary side with very few losses and to the specifications set by the client.” By Dr: Aedan Kernan
AC-DC Rectifier Converts HV-AC (LF) into HV-DC voltage Dual Active Bridge (DAB) Uses HF Transformer & Switches to Convert HV-DC into LV-DC voltage DC-AC Inverter Converts LV-DC into LV-AC (LF) voltage
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Source: http://www.marketsandmarkets.com/PressReleases/solid-transformer.asp
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B E C D
CL CL
A F LOAD DRER DESD
REL REL REL REL HV/MV (SST) Based Substation MV/LV (SST) Based Substation
SST
SST SST SST 10 kV 10 kV 400V 38 kV Section3 Section2 Section1
FID FID FID
REL REL
FID
FREEDM system
REL REL REL Distributed Renewable Energy Resources (DRERs) Distributed Energy Storage Devices (DESDs)
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A F
B E C D
CL CL LOAD DRER DESD REL REL REL REL
SST
SST SST SST 10 kV 10 kV 400V 38 kV Section3 Section2 Section1
FID FID
Voltage below 0.8 Pu IGBTs contained in the SST rectifier are blocked Current is limited to 2 pu at Terminals SST is removed by the Under Voltage Protection Current in Ter C and D Does not Exceed Maximum current
FID FID
The over current does not occur on the primary side of the SST DRER/DESD keep feeding the load as backup REL REL
REL REL
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IEC 60076-7 Loading Guide IEC 60076-5, Specifies The required short-circuit current withstand duration to be 2s.
Normal Cyclic Loading
current is applied during part of the cycle.
load
Long–Time Emergency Cyclic Loading
prolonged outage of some system elements that will not be reconnected before a steady state.
Short-Time Emergency Loading
to the occurrence of one or more unlikely events which seriously disturb normal system loading.
180% for temporary half
hour overload
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The power electronics components reduces the overload capability during load peaks. The control action could provide a solution to the overloading problem during the transients faults The SST higher realization costs do not allow to oversize In contrast with the grid components requirement of bearing currents higher than the rated values for longer periods. The SST needs new procedures for dealing with the over loading conditions
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Photovoltaic (PV) plant equipped with a Battery Energy Storage System (BESS). The BESS contributes to limit the power fluctuation in the feeder. Manage a possible overload without derating the SST. This will reduce the current and enhances the SST security against the
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Concept of the Coordinated Frequency and Voltage Overload Control. Voltage and frequency of the master controller are set to nominal values (OS I). The Master controller changes the frequency thought the DG droop controller (OS II). After 35s Insufficient power contribution is reached and DG is not sufficient to control frequency. Master controller starts changing the voltage level at LV terminal of SST The transformer overload is avoided for total
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(Physical Design)
Table 16 : IEC 61936-1 2002 Recommendations for separation distances between outdoor transformer and buildings
Transformer Type Liquid Volume (l) To Other Transformers or non Combustible Building Surfaces [m] To Combustible Building Surfaces [m] Oil Insulated Transformers > 2,000 < 20,000
5 10
ABB 10 MVA 6,156
5 10
Horizontal Separation (a) [m] Vertical Separation (b) [m]
5 15.2 5m 5m 5m 5m
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(Physical Design)
10 MVA LFT
18%
Potential Reduction
Substation Area m2 (LFT) Original Area m2 (LFT) clearance Area m2 (SST) Required Area m2 Potential Area Reduction m2
1500 12 302 6 290 Reduction Oil System Size In Volume Up to 50% SST Reduction In Volume
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Total ownership cost consist of several components:
Life Cycle Cost Breakdown Factors A, B (€/kW), that depend on transformer type, size, loading conditions, as well as cost of capital, energy market forecasts, expected transformer life.
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Costs are estimated by means of component cost models for high-volume production
expensive purchasing price.
times higher losses.
weight and volume.
with using oil.
and installation costs.
higher purchasing price and higher losses.
Weight Breakdown Material Cost Breakdown
“Solid State Transformer Market worth $204.3 Million by 2020”
MarketsandMarkets : Market Research Consulting Firm
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Unlike the conventional (LFT) the (SST) offers additional system benefits that should be considered when comparing to (LFT)
Universal Fault Isolation Instantaneous Voltage Regulations Integrates Energy Storage Actively Change Power Characteristics Improve Power Quality Provide DC Power Provides ability to utilise input or output in AC or DC power. Protects the load from power supply disturbances Eliminates the tap changer requirement Provides backup and reduces
Control voltage and frequency levels will reduce the system losses Provide reactive power compensation and system harmonic filtering In substations it could be used to feed control equipment or to feed DC micro grid
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Identify (SST) Advantages Understand (SST) Challenges Develop Comparison Framework
Grid applications
the use of oil. Protection Integration Requirement Overloading Capability Additional losses implications New Asset Reliability LFT Represents a truly Experienced Competitor to (SST) Functionality Reliability Size, Wight and Volume Efficiency / Cost SST can only be judged in the context of a given application
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Page 21 Cigré SCB1 Irishtimes.com, 'Engineers Ireland: Smart power to revolutionise future use of electricity', 2014. [Online]. Available: http://www.irishtimes.com/sponsored/engineers-ireland-smart-power-to-revolutionise-future-use-of-electricity-1.1951236. [Accessed: 27- Nov- 2015].
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Renewable Electric Energy Delivery and Management (FREEDM) System', IEEE Trans. Smart Grid, vol. 4, no. 2, pp. 1096-1104, 2013. De Carne, G.; Buticchi, G.; Liserre, M.; Marinakis, P.; Vournas, C., "Coordinated frequency and Voltage Overload Control of Smart Transformers," in PowerTech, 2015 IEEE Eindhoven , vol., no., pp.1-5, June 29 2015-July 2 2015 Huber, J.E.; Kolar, J.W., "Volume/weight/cost comparison of a 1MVA 10 kV/400 V solid-state against a conventional low-frequency distribution transformer," in Energy Conversion Congress and Exposition (ECCE), 2014 IEEE , vol., no., pp.4545-4552, 14-18 Sept. 2014
[Accessed: 27- Nov- 2015].
http://www02.abb.com/global/coabb/coabb051.nsf/0/8aa3946a6ad8e7c6c12577880053e1d8/$file/ABB+SPT+Transformers+- +Customer+Value+Proposition.pdf. [Accessed: 27- Nov- 2015].
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