Short-Term Frequency Response of a DFIG-Based Wind Turbine Generator for Rapid Frequency Stabilization

Abstract

This paper proposes a short-term frequency-response scheme of a doubly-fed induction generator (DFIG)-based wind turbine generator (WTG) for improving rotor speed recovery and frequency nadir. In the energy-releasing period, to improve the frequency nadir and rotor speed convergence by releasing a large amount of kinetic energy stored in the rotating masses in a DFIG-based WTG, the power reference is increased up to the torque limit referred to the power and reduces along with it for a predefined period which is determined based on the occurrence time of the frequency nadir in a power grid. Then, the reference decreases so that the rotor speed is forced to be converged to the preset value in the stable operating region of the rotor speed. In the energy-absorbing period, to quickly recover the rotor speed, the reference smoothly decreases with the rotor speed and time during a predefined period until it intersects with the maximum power point tracking curve. The simulation results demonstrate that the proposed scheme successfully achieves rapid frequency stabilization with the improved frequency nadir under various wind conditions based on the IEEE 14-bus system.

Electro-mechanical Modeling of Wind Turbine and Energy Storage Systems with Enhanced Inertial Response

“…If the supercapacitor is selected as 1 F, then the DC voltage will reduce to 2150 V when such amount of energy is released. According to [25], the allowable DC voltage is determined by (30), which has been simplified considering unity power factors for GSC operation.…”

“…8, WPP is connected at bus 14 of the modified IEEE 14-bus test system. The model of IEEE 14-bus test system is based on [29] and [30] and simulated in MATLAB/Simulink. Key parameters of the test system are listed in Table A Ⅳ in Appendix A.…”

Direct Sulfonamidation of Primary and Secondary Benzylic Alcohols Catalyzed by a Boronic Acid/Oxalic Acid System

“…The solvent was then evaporated, and the crude product was purified by flash chromatography on silica gel using a solid deposit technique (silica). [18] The title compound was prepared from 1-(4-bromophenyl)ethanol (102 mg) following the general procedure B and was purified with an hexane/DCM (25:75) eluent to afford an amorphous white solid. Yield: 160 mg (90 %).…”

“…4, 141.0, 137.5, 131.5, 129.5, 127.9, 127.1, 121.3, 53.1, 23.4, 21.5 ppm. [18] The title compound was prepared from 1-phenylethanol (61 mg) following the general procedure B and was purified with an hexane/DCM (25:75) eluent to afford an amorphous white solid. Yield: 137 mg (99 %).…”

Islanding Fault Detection in Microgrids—A Survey

“…However, numerous problems should be addressed before their widespread usage in the power networks. These problems include frequency stabilization (e.g., model predictive control [1], passivity-based approach [2], and Lyapunov-based approach [3]), voltage stabilization (e.g., PI controller [4], fuzzy logic [5], droop control [6], and consensus-based approach [7]), robustness against uncertainties (e.g., optimization-based approach [8], load shedding-based approach [9], neural networks [10], and three phase improved magnitude phase locked loop [11]), and tolerance toward faults (e.g., reconfiguration-based approach [12], model predictive control [13], optimization-based approach [14], model-based techniques [15], and a consensus-based approach [16]).…”