Environmental Engineering Reference
In-Depth Information
4.3.1.4 Wind farms connected directly to the
sub-transmission system
When a wind farm is connected adjacent to the sub-transmission system, the
impedance between farm and system will be dominated by transformer leakage
reactance. The series resistance is negligible. Hence any voltage variation at the
wind farm terminals will be due to reactive rather than active power flow. Thus
unity power factor generation from the wind farm creates minimum voltage fluc-
tuation at the 33 kV busbar and similarly causes a much reduced number of tap
change operations on the 132/33 kV transformers.
The graphs in Figures 4.3 and 4.4 were produced for a UK utility and show the
voltage and tap change situation for a 200 MW wind farm connected directly to the
10
5
0
-5
-10
0.9 lag
0.99 lag
unity
0.99 lead
-15
-20
-25
0
50
100
150
200
250
Generated output (MW)
Figure 4.3
Voltage step change on loss of generation plotted for different
generating outputs and power factors
0.9 lag
0.99 lag
unity
0.99 lead
1.1
1.05
1.0
0.95
0.90
0
50
100
150
200
250
Generated output (MW)
Figure 4.4
System transformer tap position for different levels of generation and
power factors
Search WWH ::
Custom Search