Operation of power systems - Wind Power Integration: Connection and System Operational Aspects - page 163

100

90 NI Total -15 min

NI Total -30 min
NI Total -60 min
NI Total -2 h
NI Total -4 h
NI Total -8 h
NI Total -12 h

80

70

60

50

40

30

20

10

0

0 10 20 30 40 50 60 70 80 90 100

Power fluctuation ( ± % available capacity)

Figure 5.17 Northern Ireland wind power fluctuations - cumulative distribution

Similarly, over the period of 1 hour, 2 hours and 4 hours the most likely maximum
variation within N. Ireland is 13, 20 and 32 per cent of wind farm capacity. Even
over a 12 hour period, the most likely maximum variation is 56 per cent of wind
farm capacity, and the probability of a 30 per cent or greater variation in production
is only 23 per cent.
All island variability
A cumulative distribution plot can now be created for the entire island, see
Figure 5.18. This looks similar in shape to Figure 5.17 for the N. Ireland region, and
Figure 5.15 for an individual wind farm, except that the normalised variability is
further reduced. For a time delay of 60 minutes, the magnitude of the wind power
fluctuations is most likely to be less than 8 per cent of wind farm capacity and
unlikely to exceed 11 per cent, both comparable with the 30 minute variations for
the N. Ireland region. Over 2 and 4 hour periods the most likely maximum variation
is 15 and 25 per cent of wind farm capacity, with the combined wind farm output
unlikely to ever vary by more than 20 and 32 per cent over the same periods.
Even over a 12 hour period, fluctuations exceeding 50 per cent occur less than
5 per cent of the time, while two thirds of the time, the same variations are less than
20 per cent of wind farm capacity.
These results confirm that a sudden collapse (or indeed rise) in wind power
generation across the island is most unlikely. One exception to this rule could be
an advancing storm front that could cause turbine high wind speed protection