A Cooperative Approach of Frequency Regulation Through Virtual Inertia Control and Enhancement of Low Voltage Ride-through in DFIG-based Wind Farm

Abstract

Doubly-fed induction generator (DFIG)-based wind farms (WFs) are interfaced with power electronic converters. Such interfaces are attributed to the low inertia generated in the WFs under high penetration and that becomes prevalent in a fault scenario. Therefore, transient stability enhancement along with frequency stability in DFIG-based WFs is a major concern in the present scenario. In this paper, a cooperative approach consisting of virtual inertia control (VIC) and a modified grid-side converter (GSC) approach for low voltage ridethrough (LVRT) is proposed to achieve fault ride-through (FRT) capabilities as per the grid code requirements (GCRs) while providing frequency support to the grid through a synthetic inertia. The proposed approach provides LVRT and reactive power compensation in the system. The participation of the VIC in a rotor-side converter (RSC) provides frequency support to the DFIG-based WFs. The combined approach supports active power compensation and provides sufficient kinetic energy support to the system in a contingency scenario. Simulation studies are carried out in MATLAB/Simulink environment for symmetrical and unsymmetrical faults. The superiority of the proposed scheme is demonstrated through analysis of the performance of the scheme and that of a series resonance bridgetype fault current limiter (SR-BFCL). Index Terms--Virtual inertia controller (VIC), doubly-fed induction generator (DFIG), fault ride-through (FRT) capability, wind farm (WF), fault current limiter (FCL).

Aggregated demand-side response in residential distribution areas based on tiered incentive prices

“…However, because resources of users in RDAs are usually widely dispersed, the response potential of a single user is limited, the current market entry threshold is relatively high, direct control is not fully realized, and a large number of DR resources have not been fully exploited. Therefore, using the idea of aggregation to integrate resources in RDAs and fully exploiting the scale effect to promote DR has become the key to promote source-load interaction (Klaucke et al, 2020;Preeti et al, 2022;Tan and Zeng, 2022).…”

Torque Limit-based Inertial Control Method Based on Delayed Support for Primary Frequency Control of Wind Turbines

“…As shown in Fig. 2, when a load surge event occurs, the TLIC method immediately increases the electrical power from P W0 to P T lim ( ω 0 ) , and sets the power P TLIC (ω) according to the rotor speed during the frequency support stage (B-C), as shown in (7). The WT operates along the preset powerspeed curve.…”

“…3) TLIC frequency support module. At t 0 + Dt delay W , the TLIC method is activated and the electrical power command of the WT is set according to (7) and (8).…”

“…Wind turbines (WTs) are urgently required to participate in the primary frequency control (PFC) [1]- [5]. According to whether the electrical power of WTs is related to the frequency, the existing PFCs can be divided into two types: PFC strategies responding to the frequency variation such as virtual inertial control [6], [7] and droop control [7], and PFC strategies presetting the power curves such as stepwise inertial control (SIC) [8]- [11] and torque limit-based inertial control (TLIC) [12] - [14]. This paper mainly focuses on the second type.…”

Dynamic State Estimation for DFIG with Unknown Inputs Based on Cubature Kalman Filter and Adaptive Interpolation

“…An appropriate dynamic model of DFIGs is critical for the DSE. In [8] and [9], the conventional control of DFIGs is modeled using the DSE, but fault control strategies [10], [11] are ignored. However, when a fault occurs, the transient dynamic process of DFIGs under the fault control strategies plays an essential role in affecting the power system dynamics, and thus should be effectively captured by the DSE [12].…”