The RSE experience with supercapacitors for the … RSE experience with supercapacitors for the...
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The RSE experience with supercapacitors for the electrical sector Luigi Pellegrino [email protected]
Transcript of The RSE experience with supercapacitors for the … RSE experience with supercapacitors for the...
The RSE experience with supercapacitors for the electrical sector
Luigi Pellegrino
Index
• Test Procedures – Characterization Test – EV Test – Aging test
• Hybrid Storage System – Control – Tests
• Grid application
– Active filter – Other Applications
Introduction
The increase of not programmable renewable energy sources (RES) introduces new problems in electrical system due to their aleatory. In this context, storage system have a main role because they allow the decoupling between loads and generators.
Supercapacitors are an electrical storage system which can provide high values of power and long lifetime. So they are used for all power applications (not only in electrical system)
It is important to continue the research on supercapacitors in order to have accurate models and new control systems that allow better design and management of these storage systems.
TEST PROCEDURES
Test Set up
IEC 62576/CDV IEC- 62391-1 IEC- 62391-2
Test bench:
• DC supplier
• Electronic load
• Data logger
• Climate chamber
SCs
Characterization tests
Faradic Capacity Maximum Energy
Internal Resistance
Peak Power
Energy Efficiency
Ah Efficiency
Ah Capacity
Self discharge
http://www.rse-web.it/documenti/documento/315290
Cells
Modules
Batteries
(Developed by RSE and ENEA)
EV Test
• HPPC test The goal of this test is to simulate the behavior of SCs battery used in Electric Vehicle
• Cold cranking test
This test verifies the ability of supercapacitors to deliver power to EV at low temperatures
• Fast charge
It simulates the regenerative braking
• Fast discharge It simulates the accelerating of EV
(Developed by RSE and ENEA)
Aging test Maxwell BCAP0350-E250
Cn [F] 350
Vn [V] 2,5
Imax [A] 21
Ipeak_max [A] 220 / 1s
Life cycle 500000
Cycles composed by a charge and a discharge between Vn and Vn/2. After 335000 cycles at 20°C the capacity lost of SCs is about 17% and the increase of internal resistance is 45%. Overall aging test duration: 1 year
HYBRID STORAGE SYSTEM
HSS - Configuration
Lithium-ion cell: 11 Ah, Vn = 3,7 V Supercapacitors: 350 F, Vmax = 5,2 V
Hybrid Storage System
Storage System
HSS - Goals
Objectives of the HSS control are:
1. Share Energy (Battery) and Power (SCs) among the installed components
2. Limiting the battery current fluctuations (hence increase battery lifetime)
3. Keep the state of charge (SOC) of SCs in a range in which SCs guarantee to compensate the peaks of current.
HSS - Control
Current loop is used to avoid that current reaches its maximum value
Voltage loop is used to regulate the output voltage of converters
HSS - test
Cycle life Load profile:
- Mean current C/2
- Peak current 1C
Parameterization test
- Test capacity
- Current pulse discharge
Cell operating range: • Cycle life: DOD = 50%, initial SOC 90% • Parameterization test: DOD = 100%, initial
SOC 100%
HSS – Results on Li-cell
10.2
10.3
10.4
10.5
10.6
10.7
10.8
0 50 100 150 200 250
Cap
acit
y [A
h]
Cycles number
Single Cell
Hybrid Cell
Capacity fed of single cell double than the cell in HSS (4,1% vs 2,1%)
HSS – Results on Li-cell Increase of internal resistance of single cell much greater than the cell in HSS (255% vs 77%)
0
5
10
15
20
25
0 50 100 150 200 250
Inte
rnal
Res
ista
nce
[mΩ
]
Cycles number
Single Cell
Hybid Cell
HSS - Conclusions
Single cell:
The increase of internal resistance is an index of state of health but also an aging factor.
HSS:
The increase of battery internal resistance is only an indicator of the state of health.
More energy available
Increase Battery lifetime
GRID APPLICATIONS
Grid applications POWER applications:
– Power Quality – Voltage control – Frequency control – Spinning reserve
ENERGY applications:
– Time shift – Peak shaving – Back-up – Non spinning reserve
Grid application – RSE Facility
DC Grid
http://www.rse-web.it/laboratori/laboratorio/32
Grid application - SC Best uses
Industrial Sector:
Drivers
Medicale Sector:
TAC, X-ray machines
Tertiary Sector:
Data center
Constant Power profile
Bidirectional power flow
Lots of Power Peaks
Needs High Power Quality
Voltage control
Regenerative Braking
Grid application - SC Best uses How SCs can help the grid? How SCs can help the user? Step load of 20 kW on DC bus
0 5 10 15 20350
360
370
380
390
400Tensione Bus in CC
Tensio
ne [
V]
0 5 10 15 20160
180
200
220
240Tensione Supercondensatori
Tempo [s]
Tensio
ne [
V]
SCs Voltage
DC bus Voltage
Vo
ltag
e [V
] V
olt
age
[V
]
Time [s]
0 5 10 15 20-10
0
10
20
30Potenza Bus in CC - Front End
Pote
nza [
kW
]
0 5 10 15 20-10
0
10
20
30Potenza Bus in CC - Supercondensatori
Pote
nza [
kW
]
0 5 10 15 20-10
0
10
20
30Potenza Bus in CC - Carico
Pote
nza [
kW
]
Tempo [s]
Power DC bus - Load
Power DC bus – Inverter
Power DC bus – SCs
Pow
er [
kW]
Pow
er [
kW]
Pow
er [
kW]
Time [s]
AC grid AC
DC
Load
DC/DC +
SCs
Grid application - SC Best uses How SCs can help the grid? How SCs can help the user? Pulsed Load of 9 kW
AC grid AC
DC
Load
DC/DC +
SCs
Po
wer
[kW
]
Time [s]
Load
AC grid provides only the average power of the load (about 4.5 kW). SCs respond to the peak of power.
Grid application - Active filter
UPS
Reactive compensator Harmonics
compensator
Load features: Sn = 10 kVA cosφ = 0.8
Maximum voltage dip = 10 s
Grid application - Active filter
power activelink DCP
power reactive VariableQ~
power active VariableP~
power reactive AverageQ power active Average P
dc
Grid
dcP
dcPP
Q
Q
PP~
QQ~
P~
P
Conv1 Conv2
Q~
Load
Grid application - Active filter Load disturbances Grid disturbances
Negligible harmonics THD < 1,7%
0 100 200 300 400 500 6000
102030405060708090
100110120130
Corrente di CARICO
|I(f
)|/|I n(5
0)| [
%]
0 50 100 150 200 250 300 350 400 450 500 550 6000
10
20
30
40
50
60
70
80
90
100
110
Frequenza [Hz]
|I(f
)|/|I n(5
0)| [
%]
Corrente di RETE
0 50 100 150 200 250 300 350 4000
10
2030
4050
6070
8090
100110
|V(f
)|/|Vn(5
0)| [
%]
Tensione di RETE
0 50 100 150 200 250 300 350 4000
10
2030
4050
6070
8090
100110
frequenza [Hz]
|V(f
)|/|Vn(5
0)| [
%]
Tensione di CARICO
Effect
Effect
Load current
Frequency [Hz]
Grid voltage
Load voltage Grid current
Frequency [Hz]
Thank you for your attention!
www.rse-web.it
This work has been financed by the Research Fund for the Italian Electrical System under the Contract Agreement between RSE S.p.A. and the Ministry of Economic Development - General Directorate for
Nuclear Energy, Renewable Energy and Energy Efficiency in compliance with the Decree of March 8, 2006.
