Proposal for a High Quality dc Network with Distributed Generation
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Transcript of Proposal for a High Quality dc Network with Distributed Generation
Agustoni IT Session 2 – Block 3
Barcelona 12-15 May 2003
Proposal for a High Quality dc Network with Distributed Generation
A. Agustoni, M. Brenna, E. TironiPolitecnico di Milano – Italy
G. UbezioSIEL S.p.A. – Italy
2Agustoni IT Session 2 – Block 3
Barcelona 12-15 May 2003
Introduction
Need of high-quality power supply
UPS with dc section
Distributed Generation
Generation in dc
Electronic devices
dc section
Integration in a local dc
distribution network
3Agustoni IT Session 2 – Block 3
Barcelona 12-15 May 2003
Comparison between ac and dc distribution systems
ac generators
storage
dc users
dc bus
public network
dc users
ac users
dc generators
ac
public network
ac generators
dc generatorsstorage
storage
ac users
ac users
dc users
dc users
4Agustoni IT Session 2 – Block 3
Barcelona 12-15 May 2003
dc distribution advantages
• Island operation
• Reduction of power converters number and their complexity
• Increase in power quality for– end users– public network
• Better integration of DG
5Agustoni IT Session 2 – Block 3
Barcelona 12-15 May 2003
dc system choice criteria
Sinusoidal absorbtion
Bidirectional power flow
Keep the same ac distribution systems apparatuses
Forced-commutated ac/dc interface converter
Same MV/LV substation transformer
dc voltage = ±400 V
6Agustoni IT Session 2 – Block 3
Barcelona 12-15 May 2003
Proposed network schemes
Use existing distribution lines
load load load
PE
DG storage
N 3 2 1
7Agustoni IT Session 2 – Block 3
Barcelona 12-15 May 2003
Proposed network schemes
Connection of the neutral to the grounding system of MV/LV substation
load load load
PE
DG storage
N 3 2 1
8Agustoni IT Session 2 – Block 3
Barcelona 12-15 May 2003
Control system – characteristics
• dc bus is the only connection common to all converters control system is based on dc voltage
• Presence of different supply sources possibility to integrate and optimize system management with field bus systems
• Control system must be robust
9Agustoni IT Session 2 – Block 3
Barcelona 12-15 May 2003
Control system – functions
• Keep dc voltage within acceptable range• Renewable generators must supply all the
available power, if loads, network or storage systems can absorb it
• Storage systems have to be recharged as soon as possible and need to be discharged if necessary
• ac/dc interface converter has to absorb or deliver power from or to the network
10Agustoni IT Session 2 – Block 3
Barcelona 12-15 May 2003
Control system – strategy
By varying the reference values is possible to adjust system performance
renewable generators
non-renewable generators
storage system – charge
public network - sale
public network - purchase
storage system - discharge
Vn
Vref ren
Vref nren
Vref net s
Vref st c
Vref net p
Vref st d
11Agustoni IT Session 2 – Block 3
Barcelona 12-15 May 2003
(f ile lv dc03ts.pl4; x-v ar t) v :DC1 -DC2*c:GEN -DC1
0.00 0.05 0.10 0.15 0.20 0.25 0.30[s]76.5
76.8
77.1
77.4
77.7
78.0
[kW]
renewable power delivered
Simulation results
(f ile lv dc03ts.pl4; x-v ar t) c:CONDAM-CONDA c:CONDBM-CONDB c:CONDCM-CONDC
0.00 0.05 0.10 0.15 0.20 0.25 0.30[s]-500
-375
-250
-125
0
125
250
375
500[A]
(f ile lv dc03ts.pl4; x-v ar t) v :DC_POS-DC_NEG v :POS1 -NEG1 v :POS2 -NEG2 v :DCPOS1-NEU1+v :NEU1 -DCNEG1
0.00 0.05 0.10 0.15 0.20 0.25 0.30[s]745
755
765
775
785
795
805
[V]
(f ile lv dc03ts.pl4; x-v ar t) c:BATTC -BATTM
0.00 0.05 0.10 0.15 0.20 0.25 0.30[s]-100
0
100
200
300
400
500
[A]
ac input currents dc bus voltage
storage system current
12Agustoni IT Session 2 – Block 3
Barcelona 12-15 May 2003
Conclusion
• A new dc distribution system has been proposed
• The system permits an increase in power quality both for end users and network
• The system allows an easier integration of DG
• It is possible to optimize the system management by means of field bus systems
13Agustoni IT Session 2 – Block 3
Barcelona 12-15 May 2003
14Agustoni IT Session 2 – Block 3
Barcelona 12-15 May 2003
Simulation results
(f ile lv dc03ts.pl4; x-v ar t) t: PTR
0.00 0.05 0.10 0.15 0.20 0.25 0.30[s]-20
0
20
40
60
80
100
120
*103
(f ile lv dc03ts.pl4; x-v ar t) v :CARA -NEU2 v :CARB -NEU2 v :CARC -NEU2
0.00 0.05 0.10 0.15 0.20 0.25 0.30[s]-400
-300
-200
-100
0
100
200
300
400[V]
power absorbed from the network ac voltages
15Agustoni IT Session 2 – Block 3
Barcelona 12-15 May 2003
Simulation results
(f ile lv dc03ts.pl4; x-v ar t) c:CONDAM-CONDA c:CONDBM-CONDB c:CONDCM-CONDC
0.00 0.04 0.08 0.12 0.16 0.20[s]-60
-34
-8
18
44
70
[A]
(f ile lv dc03ts.pl4; x-v ar t) c:CONDAM-CONDA v :CONDAM
0.00 0.04 0.08 0.12 0.16 0.20[s]-400
-300
-200
-100
0
100
200
300
400
(f ile lv dc03ts.pl4; x-v ar t) v :DC_POS-DC_NEG v :POS1 -NEG1 v :POS2 -NEG2 v :DCPOS1-NEU1+v :NEU1 -DCNEG1
0.00 0.04 0.08 0.12 0.16 0.20[s]780
785
790
795
800
805
810
815[V]
(f ile lv dc03ts.pl4; x-v ar t) c:BATTC -BATTM
0.00 0.04 0.08 0.12 0.16 0.20[s]-90
-70
-50
-30
-10
10
[A]
ac input currents ac input current and phase voltage
dc bus voltage storage system current
16Agustoni IT Session 2 – Block 3
Barcelona 12-15 May 2003
Simulation results
(f ile lv dc03ts.pl4; x-v ar t) t: PTR
0.00 0.04 0.08 0.12 0.16 0.20[s]-30
-20
-10
0
10
20
30
40
*103
(f ile lv dc03ts.pl4; x-v ar t) v :DC1 -DC2*c:GEN -DC1
0.00 0.04 0.08 0.12 0.16 0.20[s]76.5
76.8
77.1
77.4
77.7
78.0
[kW]
(f ile lv dc03ts.pl4; x-v ar t) v :CARA -NEU2 v :CARB -NEU2 v :CARC -NEU2
0.00 0.04 0.08 0.12 0.16 0.20[s]-400
-300
-200
-100
0
100
200
300
400[V]
power absorbed from the network renewable power delivered
ac voltages
17Agustoni IT Session 2 – Block 3
Barcelona 12-15 May 2003
A dc distribution system realization
Inverter
Storage system
Auxiliary generator
Rectifier
Loads
DC-DCConverter
DC Bus
Photovoltaic arrays