Title :
Sensitivity Analysis of Load-Damping Characteristic in Power System Frequency Regulation
Author :
Hao Huang ; Fangxing Li
Author_Institution :
Dept. of Electr. Eng. & Comput. Sci., Univ. of Tennessee, Knoxville, TN, USA
Abstract :
The smart grid initiative leads to growing interests in demand responses and the load models, especially the frequency-sensitive loads such as motors. The reason is that high-penetration controllable load may have substantial impact on system frequency response (SFR). However, the effect of the frequency-related load-damping coefficient is still not completely understood. This paper investigates the effect of frequency-sensitive load on system frequency using typical SFR model. Theoretic analyses based on transfer functions show that the frequency deviation under a different load-damping coefficient is relatively small and bounded when the power system is essentially stable; while the frequency deviation can be accelerated when a power system is unstable after disturbance. For the stable case, the largest frequency dip under a perturbation and the corresponding critical time can be derived by inverse Laplace transformation using a full model considering load-damping coefficient. Further, the error in evaluating the load-frequency coefficient gives the largest impact to frequency deviation right at the time when the largest frequency dip occurs. Multiple-machine cases and automatic generation control (AGC) are also included in the analyses with verifications by simulation studies. The conclusion can be useful for system operators for decision-making of load control or interruption.
Keywords :
Laplace transforms; automatic gain control; decision making; frequency control; load regulation; perturbation techniques; power system control; sensitivity analysis; smart power grids; AGC; SFR model; automatic generation control; decision making; demand responses; frequency deviation; frequency dip; frequency-related load-damping coefficient; frequency-sensitive load; frequency-sensitive loads; inverse Laplace transformation; load control; load interruption; load-damping characteristic; load-damping coefficient; load-frequency coefficient; perturbation; power system; power system frequency regulation; sensitivity analysis; smart grid initiative; system frequency response; system operators; theoretic analyses; Automatic generation control; Frequency control; Load modeling; Power system stability; Sensitivity; Stability analysis; Transfer functions; Automatic generation control (AGC); demand response; frequency drop; frequency sensitive load; load control; sensitivity analysis; system frequency response (SFR);
Journal_Title :
Power Systems, IEEE Transactions on
DOI :
10.1109/TPWRS.2012.2209901