Transcript Probabilistic planning for a higher integration of wind turbines to MV

Frankfurt (Germany), 6-9 June 2011
PROBABILISTIC PLANNING
FOR A HIGHER INTEGRATION OF
WIND TURBINES
TO MV DISTRIBUTION NETWORKS
Walter Niederhuemer
Karl Derler
Linz Strom Netz GmbH
W. Niederhuemer – Austria – RIF Session 4 – Paper 1100
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Frankfurt (Germany), 6-9 June 2011
Introduction
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Feed in by onshore wind turbines into MV-grids is a
particular challenge for the DSO
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Requests for connections primarily for several wind turbines or
small wind farms
Power range of a few MW
Connections distributed across the same part of the MVdistribution network
To enable the feed in and guarantee the power quality
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Reduction of the installed feed in power is necessary
Extending the distribution network
W. Niederhuemer – Austria – RIF Session 4 – Paper 1100
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Frankfurt (Germany), 6-9 June 2011
Introduction
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Producer and DSO with different optimum
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Producer
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DSO
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Deliver full feed in power at any time
Increase the energy output and thus to optimize the return
Low direct grid connection costs
Keep the network cost as low as possible
To support the objectives of the EU and to enable more
feeding in, it is necessary
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To find an overall economic optimum
To find a compromise between network investments and
produces energy quantity
W. Niederhuemer – Austria – RIF Session 4 – Paper 1100
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Frankfurt (Germany), 6-9 June 2011
Method of calculation
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Probabilistic calculation
Taking into account the
statistical behavior of
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Output voltage in the substation
Current in the branch
Feed in power of the wind turbine
W. Niederhuemer – Austria – RIF Session 4 – Paper 1100
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Frankfurt (Germany), 6-9 June 2011
Result of the conventional assessment
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Selected network
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Conventional assessment
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1,2MW wind turbine +
250kW biogas plant
connected
New 2MW wind turbine
is planned
Connection via 17,5km
overhead line 95mm²
Aldrey
Peak load with and
without feeding
Off-peak load with and
without feeding
Reduction of installed feed in power to 2,2 MW is necessary
Alternatively, 0,5Mio€ investment to the grid for a 3km long MV cable
W. Niederhuemer – Austria – RIF Session 4 – Paper 1100
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Frankfurt (Germany), 6-9 June 2011
Result of the probabilistic calculation
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0,03% not feed in energy
Reduction of active power
up to max. 1370kW
27,45
feed in power at PCC: 3,2 MW wind turbine
28,0
Maximum acceptable
voltage in the MV-network
26,41
27,0
26,5
26,90
27,5
26,18
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Cumulated relative frequency distribution
voltage at PCC
26,0
25,5
25,96
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Installed wind turbine
power 3,2MW
Voltage exceeds the
voltage limit only for a few
hours.
Theoretically generated
annual amount of energy
about 3.000 MWh
With active power control
Voltage [kV]
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25,0
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Cumulated relative frequency
Annual revenue loss is less than 100€ (with feed-in tariff of 9,6ct/kWh)
W. Niederhuemer – Austria – RIF Session 4 – Paper 1100
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Frankfurt (Germany), 6-9 June 2011
Result of the probabilistic calculation
If a not feed in energy amount of 5% is acceptable for producers
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7,5MW wind turbine power could be installed at the PCC
Theoretically generated
annual amount of energy
about 7.000 MWh
With active power control
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5% not feed in energy
Real feed in energy
6.650 MWh
Reduction of active power
up to max. 3,8MW (50% of
installed feed in power)
Yearly earning of energy of on-shore wind turbines and loss
because of control or switch off if voltage level is too high
8.000
7.000
feed in energy [MWh]
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~5% of not feed in
energy
6.000
5.000
4.000
3.000
2.000
3000
4000
5000
theoreticaly feed in energy [kWh]
real feed in energy [kWh] (switch off)
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6000
7000
8000
9000
installed wind generation power [kW]
real feed in energy [kWh] (active power control)
2 times higher energy yield without additional grid investments
W. Niederhuemer – Austria – RIF Session 4 – Paper 1100
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Frankfurt (Germany), 6-9 June 2011
Conclusion
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Probabilistic planning allows a better simulation of real
network conditions
More than 2 times higher generation capacity by minimal
network costs
Acceptance by producers of a certain amount of not feed
in energy is necessary
Need of construction cost contribution for future grid
investments
Need of suitable legal frameworks
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