Transcript Verteilnetze in Deutschland

Universität Dortmund
Fakultät für Elektrotechnik und Informationstechnik
Lehrstuhl für Energiesysteme und Energiewirtschaft
Prof. Dr.-Ing. E. Handschin
Distribution networks in Germany
Lecture at the Universidad de Chile
20.04.2005
Prof.-Dr.-Ing. E. Handschin
[email protected]
•
Basic data of the German electricity network
•
Decentralised power supply
•
Supply reliability
•
Communication networks for the power supply
•
Powerline in low tension networks
•
Operating state diagnostic
•
Conclusion, Outlook
Content
2
German Extra-High Voltage Network
Control areas
1
2
3
4
EnBW Transportnetze AG
E.ON Netz GmbH
RWE Net AG
Vattenfall Europe Transmission GmbH
Basic data of the German electricity network
3
Grid type
Circuit lengths
in km
Cable rate
in %
eHV and HV
111.400
4
MV
490.600
65
LV
1.039.500
72
total
1.641.500
63
age pattern of the cables
age pattern of the equipment
Cables and overhead lines
4
Electricity network operators
approx. 900 mains supply operators
Point of origin
supply interruption
(in %)
Plants
~0
(except heavy troubles)
220-/380-kVGrids
~ 0,1
(except heavy troubles)
110-kV-Grids
~2
MT-Grids
~ 80
LT-Grids
~ 20
Distribution networks in Germany
5
60,00
Value added tax (16%)
€ / Month
50,00
ecological tax
40,00
Renewable-EnergySources-Act (EGG)
30,00
cogeneration act
20,00
concession levy
10,00
power generation.
-transport and -distribution
0,00
1998
2000
2002
2004
Average electricity bill of a three-person-household per
month in € (Source VDEW)
6
Replacement of Investment
installed power in Germany
Water
Wind
?
Other thermal
Oil
Natural Gas
Hard Coal
Lignite
Uranium
Power capacity 2002 till 2030
7
Decentralised
Energy Conversion
Systems
natural and bio-gas
regenerative
Photovoltaic
Wind energy Hydro
•...
100 kW
•
... 2000 kW
•
•...
2000 h/a
•
... 3000 h/a
• ...
DC
AC
DC
AC
~
.. 2000 kW
5000 h/a
~
Gasmotor
Gasturbine Stirlingmotor
Microturbine
Fuel Cell
•
... 250 kW
•
... 200 kW
•
... 250 kW
•
... 8000 h/a
•
... 8000 h/a
•
... 8000 h/a
DC
AC
~
DC
AC
~
DC
AC
Technologies of DECS
8
Technology
Electricity network
Heat /
Cooling energy
Other functions
Biomass CCP
Base- /Middle-Load
Connection: MV-/HV-Net
Heat production in all Reserve and balance
temperature ranges
power
Heat storage
Geothermal
plant
Base- /Middle-Load
Connection: MV-/HV-Net
Temperature range
< 200 °C
Short term for peak load
possible
Wind energy
conversion
Medium load
Connection: MV-Net
none
Large wind farms may
produce hydrogen
Photovoltaic
Connection: LV-Net
Temperature range ≤
100 0 C
none
Micro gas
turbine
Medium-/ peak load
Connection: LV Net
Temperature range
200 – 500 °C
Low
temperature FC
Medium-/ peak load
Connection: NS
Temperature range
< 200 °C
High
temperature FC
Base-/ middle load
Connection:MV Net
Temperature range
> 200 °C
Large building supply
Load management
Control and reserve power
in combination with a
virtual power plant
Alternative fuels
Characteristics of dispersed generation plants
9
[TWh]
60
50
40
30
20
10
0
1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004
Hydropower
Wind power
Biomass
Photovoltaic
Contribution of the renewable energies to
power generation 1990 – 2004 (source:BMU)
10
Problems:
 Flexibility of generation and distribution
Large power plants
supply all customers
 Operating costs
Power plants
 Approval of projects
110/220/380 kV
 Supply quality
10/20 kV
 Developing countries
0,4 kV
Household
Industry
Present Structure of Electric Power Systems
11
Advantages:
Storage
Industry
Power
Quality
Dispersed generation
Energy storage
Power quality
+
Household
Metering
Intelligent communication systems
+
Solar
Storage
110 kV
10/20 kV
Fuel Cell
0,4 kV
Decentralised energy
management systems
=
Combined
cycle plant
Wind
The Electric Power
Network of the Future
Centralized / Decentralized Electric Power Systems
12
Today
Yesterday
WEC
10 kV
10 kV
Tomorrow
~
10 kV
WEC
10 kV
~
10 kV
10 kV
Electricity
Heat/Cold
IT
Water
FC
0,4 kV
~
0,4 kV
~
~
~
PV
PV
PV
0,4 kV
~
FC
~
~
FC
FC
~
PV
~
FC
~
PV
The Distribution Grid Structure in Comparison
13
Integration of DG in the Distribution Network
+ Superposition of perturbations, in
particular for f > 2,5 kHz
+ Installed Protection must be re-designed
+ Liberalization
+ Ancillary Services
+ ...
Definition of supplementary
supply conditions
Technical
+ Economical
+ legal
= Integration
Individual Integration
Fixed Integration
Spectral Network Impedance
Distribution Capacity
Certification
Network Protection
Need for Action
14
Grid impedance at PCC
h
UN
hZ
h
h
ZN
10 kV
1
1
PCC
h UN
0,4 kV
ZT
hZÜ1
Transformer
h ZÜ2
Cable /
hZÜ4 overhead
line
CK
Systemcapacities
h
Z 1 = f ( Z N, Z T, Z I, Z Ü, x, t, h )
Measurement at PCC
1
PCC
Point of
Common Coupling
h
IV
hZ
h
ZI
h
I Um
Household supply
connection with inverter,
load and source of
interference
Extended connecting conditions
1
1
PCC
h
h UN
IM
External AC-Source
spectral grid impedance I
15
4
Z
[W]
Compatibility level
for U
3,5
Mathematical result
3
2,5
Impedance characteristic
curve at PCC
2
measurement
1,5
1
0,5
f
Individual
Compatibility level
[Hz ]
15
0
30
0
45
0
60
0
75
0
90
0
10
50
12
00
13
50
15
00
16
50
18
00
19
50
21
00
22
50
24
00
25
50
27
00
28
50
30
00
31
50
33
00
34
50
36
00
37
50
39
00
40
50
42
00
43
50
45
00
46
50
48
00
49
50
0
Current characteristic
curve Inverter
Individual
compatibility level
Connection
Spectral Grid-impedance characteristic curve as basic connection condition
Extended connecting conditions
spectral Grid impedance
16
 Main operators are obliged to
supply customers in the LV-grid
with supply voltage in interval
Un-10% < U< Un+ 10% (DIN
IEC 38).
Usoll,UW= 10,6 kV
Usoll,UW= 10,2 kV
 Voltage control for MV- and LVgrids takes place centrally at
the power substation (PS).
 Problems for voltage control
in grids with distributing
poles (dp) with high load
and feeding
load flow
voltage drop
U= 10,9 kV
U= 10,6 kV
U= 9,7 kV
U= 9,4 kV
 voltage decrease for the right
distributing pole
 voltage increase for the left
distributing pole
feeding:
P= 4,3 MW
Q= 2,1 MVar
load:
PL= 4,3 MW
QL= 2,1 MVar
Voltage scheduling
17
MVunit
short-circuit power
high
voltage
bus
MVunit
 Dimensioning of the dynamic short
circuit power considers only the
contribution of the feeding grid.
 At the 100 % level of the dynamic
strength determined by the feeding
network increased risk in the direct
vicinity of the substation.
G
G
G
G
G
G
G
G
Short circuit power
18
K01
K03
ONT
• Failure
Disconnection
10 kV / 0,4 kV
• Maintenance
Disconnection
10 kV
Grid
K02
DG in grid coupled Mode
K04
~
Consequences of islanding
in grid coupled operation
Islanding can occur
in grid coupled operation
 Lost of the MV-Grid because of failures
or unbalanced Power
 Lost of the LV-Grid at service entrance
box because of failures
 NO zero voltage operation warranted
 short-term feeding of short circuits
 High thermal load of inverters and other
Grid components
 Voltage procrastination in case of
 Operational disconnection at local grid
transformer by the power company
single-phase connection
 Lost of the selective protection (error location)
Islanding
19
System Configuration
20
Voltage inhouse
Powerline
Source: http://www.its05.de/html/powerline.html
21
visualization
coordination
visualization
visualization
coordination
coordination
WT1 PV1 PV2
FC1
visualization
visualization
coordination
coordination
MT1
MT2 WT2 FC2 WT3
MT3 FC3 PV3
FC:
WT:
PV:
MT:
fuel cell
wind turbine
photovoltaic
micro turbine
Distributed Hierachical Energy Management System
22
Asymmetry
Unbalanced allocation of 1-phase loads, as well as the operation of
2-phase loads stress transformers and grids asymmetric.
Asymmetric operation of the grid can have different effects
 unbalanced transformer load, -losses, -hum
 Motors are running unbalanced
 high losses
 short durability
 abrasion of bearings
 undefined reactive current compensation (Costs)
Asymmetry
23
• Summarising of single devices to classes, which are
characterised by same lifetime-cycles
• Statistical model of aging- and innovation processes
• Evaluation of expected failure rates
• Long-term prediction of maintenance and replacement
• Comparison of different maintenance and replacement
strategies
Maintenance and replacement strategies of distribution
networks
24
Modelling of aging processes
Maximum age
Aging process influenced by
maintenance measures
History of maintenance
and replacement of each
class
Simulator
routine
Maintenance and
replacement strategy
(chronological or budget)
Requirement
Maintenance
Renewal
Replacement
unplanned
Failure
rates
Maintenance and renewal strategies of distribution
networks
25
2% replacement per year
failure rate per year
Replacement and
failure rate [1/a]
2,5% replacement per year
failure rate per year
Period of rising replacement
requirement
in case of strategy “2% per year”
failure rate > 2%
0,03
0,02
0,01
0
0
1
2
3
4
5
6
7
8
9
10
Year
Influence of different replacement strategies
26
 Currently there is only limited experience with dispersed generation (DG)
within the distribution network
 A high penetration of dispersed generation requires detailed investigations,
concentrating on protection devices and power quality; existing distribution
networks were planned under different operating conditions
 Increasing penetration of DG leads to new requirements of the network
operation
 Economic operation of virtual power plants needs a new energy
management system (Multi agent real-time system)
 The virtual power plant characterizes the future vision of distribution
systems
 Maintenance and replacement strategies have to be optimized to reduce
distribution network costs
CONCLUSIONS
27