Environmental Engineering Reference
In-Depth Information
(a)
(b)
0.50
0.50
0.45
0.45
15 geographically
dispersed wind farms
Look-ahead 1 h
0.40
Single wind farm
Look-ahead 1 h
0.40
0.35
0.35
0.30
0.30
0.25
0.25
0.20
0.20
0.15
0.15
0.10
0.10
0.05
0.05
0.00
0.00
0.50
0.50
0.45
0.45
0.40
0.40
Single wind farm
Look-ahead 6 h
15 geographically
dispersed wind farms
Look-ahead 6 h
0.35
0.35
0.30
0.30
0.25
0.25
0.20
0.20
0.15
0.15
0.10
0.10
0.05
0.05
0.00
0.00
-1
-0.8 -0.6 -0.4 -0.2
0
0.2
0.4
0.6
0.8
1
-1
-0.8 -0.6 -0.4 -0.2
0
0.2
0.4
0.6
0.8
1
Normalised power forecast error (pu)
Normalised power forecast error (pu)
Figure 6.8
Error distribution for the basic persistence model for look-ahead times
of 1 and 6 hours for (a) single wind farm and (b) 15 geographically
dispersed wind farms
Figure 6.9 against look-ahead time. The improvement in both cases is clearly seen
at longer look-ahead times.
6.5
Advanced wind power forecasting systems
The flows of information into and out of a typical wind power forecasting system are
shown in the schematic diagram in Figure 6.10. At the heart of the system is the
wind power forecasting model which takes inputs from the meteorological service
and the wind farms, and provides the wind power forecasts to the main users, that is,
the TSO, energy traders and the wind farm owners. In doing so it performs a number
of key tasks: (i) downscaling, (ii) conversion of wind forecast to power forecast and
(iii) up-scaling. These are described later. The system works online, updating the
forecasts at least as often as the NWP forecast is updated. For a typical application,
covering many wind farms dispersed over a large geographic area, the importance of
a robust, efficient, secure and reliable communication system is clear.
The main input is the NWP forecast, usually provided by a national meteor-
ological service. The accuracy of the NWP model is critical in determining the
overall accuracy of the wind power forecasting system for look-ahead times greater
than 6 hours. The NWP forecast is dynamic in the sense that it might be provided
typically every 6 hours, with hourly look-ahead times extending out to 48 hours.
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