Abstract:
The inexact power output from a pitch anglecontrolled
(PAC) horizontal-axis turbine, as influenced by short
duration wind variations like turbulence and gusts, has been the
subject of well-documented experimental and empirical studies. In
this paper, an analytical interpretation of the phenomena is presented
under assumption of two-parameter Weibull statistics for
short duration wind variations. The popular concept of turbulence
intensity is used as a parametric measure for randomness of wind
speed. The formulations culminate in analytical expressions for two
distinct metrics of power distortion, namely: (a) the short duration
output power from the turbine as a mean distinct from corresponding
ideal zero-turbulence value; and (b) the output power variability
as a quantification of randomness around the mean. Estimates of
both metrics are presented for operating conditions in accordance
with the well-known IEC 61400-1 standards. Trends indicated by
computed estimates are found to be consistent with empirically
observed data from field studies that are reported in the literature
