Time-Frequency-Based Instantaneous Power Components for Transient Disturbances According to IEEE Standard 1459

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

“…These interference terms show energy content of unnecessary frequency components that actually do not exist in the signal and result in inaccurate assessment. Among all TFDs, RIDB shows the most suitable properties to minimize the interference terms [13], [17], [18]. Therefore, in this work, RIDB is chosen for the analysis of wind power grid codes under unbalanced and distorted grid conditions.…”

“…Thus, CTFD represents complex power in time-frequency domain, and real part and imaginary part of the CTFD provide active and reactive power information for a pair of voltage and current signals, respectively. Employing the CTFD, average active and reactive power under unbalanced and distorted grid conditions can be obtained as follows [13]:…”

“…FFT-based method is commonly used to assess the power quantities such as RMS voltage, power factor, active and reactive power, and provide useful information for SCADA system of WPPs. The FFT requires the signal to be periodic in nature, and only provides accurate assessment in steadystate [13], [14]. However, a WPP may introduce low voltage at POI caused by a power system fault [9], [15].…”

“…Therefore, application of time-frequency analysis (TFA) is motivated for the study of non-stationary signals in electric power systems, as it provides more accurate assessment than the conventional FFT. Also, it has the capability to present simultaneous time and variable frequency information of non-stationary signals [13], [21]. 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 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].…”