Introducing low‐order system frequency response modelling of a future power system with high penetration of wind power plants with frequency support capabilities

Abstract

Wind power generation has reached a significant share in power systems worldwide and will continue to increase. As the converter-connected generation reduces the grid inertia, more and more interest has been given to exploiting the kinetic energy and controllability of variable-speed wind turbine generators (VSWTGs) for frequency support. Consequently, the grid frequency dynamics are changing. Thus, it is necessary to include the frequency response of wind power plants in the system frequency response (SFR) model. A novel approach to low-order SFR modelling of a future power system with a high share of frequency-support-capable VSWTGs has been presented. Low-order model of VSWTGs with primary frequency response and natural inertial response has been developed considering different wind turbine operating regimes and compared to the nonlinear model for validation. Low-order model has been presented in a symbolic transfer function form. Model accuracy has been discussed and the impact of VSWTG parameters on frequency response has been analysed. The developed model facilitates studying power system frequency dynamics by avoiding the need for modelling complex VSWTG systems, while retaining a satisfying level of accuracy.

Aggregation Frequency Response Modeling for Wind Power Plants With Primary Frequency Regulation Service

“…where P m is the mechanical power, ρ is the air density, r is the blade length, v is the wind speed, C p is the coefficient of the performance of the wind turbine, λ is the tip-speed ratio, β is the blade pitch angle, P base is the rated power of the WTG, k p is the scaling factor, P e is the electrical power, P del is the deloaded power, d is the deloading percentage, P max is the maximum power, ω is the current rotor speed, and ω max and ω del are the rotor speeds at P max and P del , respectively. Here, we assume that all WTGs in this region are exposed to a constant wind speed pattern [25], the frequency response model of a WTG is analyzed using small signal analysis in this part [26]. The small signal state equation can be written as:…”

“…The idea of multi-WTG aggregation is to merge the WTGs one by one. Since the parameters k, d, and p can be obtained directly by the weighted average coefficient k m as shown in (25), only the equivalent process of parameter q needs to be proved here, as shown in Fig. 8.…”

Gain Scheduled Torque Compensation of PMSG-Based Wind Turbine for Frequency Regulation in an Isolated Grid

“…According to the motion equation and mechanical power of WTG in [28], linearized equation can be expressed by Equation (5).…”

“…WTG needs some power reserves to regulate frequency and balance power [5][6][7][8][9]. WTGs can obtain power reserves mainly in three ways: external energy storage system (ESS), pitch system and converter system [10][11][12][13][14].…”

Innovative primary frequency control in low‐inertia power systems based on wide‐area RoCoF sharing

“…Traditionally, hydro‐power plants are the first option to contribute the most on frequency control in power systems due to its capability to quickly control the water flowing in the turbines through its governor. Hydro‐controls, also known as hydro‐governors, are modelled using transfer functions of first order composed by gains and time constants [7]. In order to address this challenge and improve the hydro‐governor's actions, two groups of techniques have been observed in the literature.…”