TY - JOUR
T1 - Damping and relative mode-shape estimation in near real-time through phasor approach
AU - Chaudhuri, Nilanjan Ray
AU - Chaudhuri, Balarko
N1 - Funding Information:
Manuscript received November 27, 2009; revised December 03, 2009, February 15, 2010, and March 23, 2010; accepted April 06, 2010. First published May 24, 2010; current version published January 21, 2011. This work was supported by the EPSRC UK under grant EESC P11121. Paper no. TPWRS-00923-2009.
PY - 2011/2
Y1 - 2011/2
N2 - A technique for estimating damping and electromechanical mode-shape in near real-time as oscillations develop under transient condition is presented. At each sampling instant, measured signals are expressed as phasors using corrected values of modal frequencies. Damping is obtained from the exponential variation of estimated phasor magnitude using a moving window least squares (LS) algorithm. The relative mode-shape is computed directly from the magnitude and phase angle of the phasors. Random variations in loads are considered to examine possible impact on phasor estimation, especially the frequency correction loop. Accuracy and speed of convergence is validated by comparing the time variation of estimated dampings and relative mode-shapes against the actual values obtained from the linearized models under respective operating conditions. Besides the well-known four-machine, two-area test system, a 16-machine, five-area system is considered for illustration of the concept. Monte Carlo simulations are used to capture the statistical variability in estimation as a result of persistent disturbances (e.g., random fluctuations in loads) leading to different signal-to-noise ratios (SNRs). Results from a commercial real-time simulator illustrate the practical feasibility of the proposed approach.
AB - A technique for estimating damping and electromechanical mode-shape in near real-time as oscillations develop under transient condition is presented. At each sampling instant, measured signals are expressed as phasors using corrected values of modal frequencies. Damping is obtained from the exponential variation of estimated phasor magnitude using a moving window least squares (LS) algorithm. The relative mode-shape is computed directly from the magnitude and phase angle of the phasors. Random variations in loads are considered to examine possible impact on phasor estimation, especially the frequency correction loop. Accuracy and speed of convergence is validated by comparing the time variation of estimated dampings and relative mode-shapes against the actual values obtained from the linearized models under respective operating conditions. Besides the well-known four-machine, two-area test system, a 16-machine, five-area system is considered for illustration of the concept. Monte Carlo simulations are used to capture the statistical variability in estimation as a result of persistent disturbances (e.g., random fluctuations in loads) leading to different signal-to-noise ratios (SNRs). Results from a commercial real-time simulator illustrate the practical feasibility of the proposed approach.
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U2 - 10.1109/TPWRS.2010.2049386
DO - 10.1109/TPWRS.2010.2049386
M3 - Article
AN - SCOPUS:79151482220
SN - 0885-8950
VL - 26
SP - 364
EP - 373
JO - IEEE Transactions on Power Systems
JF - IEEE Transactions on Power Systems
IS - 1
M1 - 5471110
ER -