Analytical evaluation of control strategies for participation of doubly fed induction generator‐based wind farms in power system short‐term frequency regulation

Abstract

Increase in doubly fed induction generator (DFIG)-based wind farms degrades the short-term frequency regulation of power systems. However, such wind farms may have large amount of kinetic energy which can be rapidly injected into the power system to support system frequency by using an appropriate supplementary control loop. This study first analyses the impacts of DFIGs and their supplementary loop on power system short-term frequency regulation. Then, the average power system frequency model is modified to include the participation of wind farms in frequency control. Moreover, a new method is proposed to derive an analytical expression for minimum frequency of a power system, as an important index of frequency regulation, after a power imbalance occurrence. This analytical expression provides a tool for better insight into frequency behaviour of power systems with high levels of wind generation. The results of the analysis are verified by simulation of the nine-bus test system, using MATLAB/SIMULINK.

Review of Inertial Control Methods for DFIG-Based Wind Turbines

“…With increasing penetration of wind energy in the grid and stand-alone system, DFIG controllers should be optimally tuned so as to optimize the performance of DFIG wind turbine system during frequency excursion. Reference [21] analyses the impacts of DFIGs and their supplementary loop on power system short-term frequency regulation. The research in the field of inertia International Journal of Electrical Energy, Vol.…”

The Research on Second-Order ADRC Algorithm of Using Wind Turbine Virtual Inertia to Participate in Primary Frequency Regulation in a Small Stand-Alone Microgrid

“…The other is virtual inertia control (VIC) [12]; since the WTG itself has mechanical inertia, it has available rotor kinetic energy in operation. The rotor kinetic energy can transform into electromagnetic power through the control algorithm, to provide support for the system frequency, and this process takes a short time and "zero power consumption" [13,14]. In addition, the permeability of wind power is often larger due to the limited capacity of SSM, which ensures the effectiveness of WTG participating in the system transient frequency regulation [15][16][17].…”

“…The paper [13] introduces a method of PD-VIC to improve the primary frequency contribution of grid-connected variable speed WTG; by adjusting the droop of the WTG in response to wind velocities, the system primary frequency response is significantly improved. In [14], it is concluded that WTG can provide an extra active power production from its stored kinetic energy; the amount of extra injected power is determined according to the frequency deviation Δ and/or the rate of change of frequency / .…”

Analytical model of composite inertia control for wind turbine generators participating in frequency regulation

“…However, it does not respond to the frequency change and cannot track the wind, thus can only be used for temporary overproduction [13]. For the VIC, Akbari et al [14] open the feedback control loop and simplify the inertial loop to the integral to exactly predict the frequency nadir; however, the system response and the rotor speed change of the VSWTGs are ignored.…”