Power quality impact of wind turbine generators on the electrical grid

Abstract

The present and future dependability of the smart electric grid depends greatly upon the interaction of the grid with wind turbine generators (WTGs). WTGs can introduce power quality disturbances that have time-varying frequency components which are difficult to quantify and alleviate. This work uses time-frequency analysis to study such transient disturbances measured over a 6 year period and analyze trends based upon time-frequency tools. It is concluded that in observing instantaneous power quality indices, frequency marginals, and timefrequency distributions of measured transient voltage waveforms, the proper tools are in place to design electronics to compensate for the harmful effects of the disturbances.

Time-frequency-based assessment of grid frequency deviation caused by wind power fluctuations

“…Time-frequency distribution can be another alternative way to assess grid frequency deviation as it can provide variable frequency information under wind power fluctuations [15]- [16]. In this paper, we employ time-frequency distribution technique in order to assess the grid frequency deviation caused by wind power fluctuations in fixed speed wind energy conversion system.…”

A New Perspective of Wind Power Grid Codes Under Unbalanced and Distorted Grid Conditions

“…Under such conditions, signal becomes aperiodic, and frequency contents of the signal change with time as well. Hence, FFT-based method provides erroneous results in the presence of real world disturbances [17], [18]. Also, it cannot extract dynamic signature of the disturbance events since computation is performed in frequency domain only [19], [20].…”

“…TFA has been applied to several areas of power and energy systems such as in power electronics, detection and classification of power-quality (PQ) disturbances [19], and mechanical fault detection in induction motors [19]- [21]. The application of TFA in wind power has been demonstrated in the research work of [17], [18], [21]. However, assessment of RMS voltage, power factor, and data acquisition for supervisory control system under unbalanced and distorted conditions in accordance with wind power grid codes have not been studied in these works.…”

“…However, assessment of RMS voltage, power factor, and data acquisition for supervisory control system under unbalanced and distorted conditions in accordance with wind power grid codes have not been studied in these works. Also, in [17], [18], [21] TFA-based instantaneous THD is employed for the analysis of wind power impacts on the grid. The method defines THD based on the energy ratio of fundamental and harmonic components instead of the RMS values.…”

“…The method defines THD based on the energy ratio of fundamental and harmonic components instead of the RMS values. Nonetheless, [17], [18], [21] provide inaccurate assessments of wind power impacts on the grid [13].…”