Maximising wind turbine generator capacity at 11 kV

The paper is concerned with the challenges posed by the connection of wind turbine generators at a distribution voltage such as 11 kV, The capacity that can be connected within normal Distribution Code and operational limits is examined for a representative 11-kV rural feeder. The contrasting cases of concentrated and distributed generation are considered. It has been found that a modest reduction in power factor at higher loads, coupled with modified control of substation voltage, permits at least a doubling of the connected capacity. The reduced power factor at higher generation results in an increase in losses. However, it is shown that connecting the surplus power factor correction capacitance at times of heavy demand can recoup about half of the extra losses. It is also shown how the transients resulting from capacitor switching may be mitigated.