Reactive power control of DFIG wind turbines for power oscillation damping under a wide range of operating conditions

Abstract

This paper analyses the effect of replacing existing synchronous generators equipped with power system stabilizers (PSS) by DFIG based wind farms on the damping of power system oscillations in a multi-machine power system. A power system stabiliser was designed to enhance the capability of DFIG to damp power systems oscillations. The validity and effectiveness of the proposed controller are demonstrated on the widely used New England 10-machine 39-bus test system that combines conventional synchronous generators and DFIG based wind farms using eigenvalue analysis and nonlinear simulation. The nonlinear simulation is used to demonstrate how the damping contribution of DFIG based wind farms is affected by different operating conditions within the same wind farm and stochastic wind speed behaviour. The results show that installing conventional fixed parameters PSS within reactive power control loop of DFIG rotor side converter has a positive damping contribution for a wide range of operating conditions. Furthermore, the results clearly show that DFIG based wind farms equipped with the proposed farm level PSS can damp power system oscillations more effectively than synchronous generators PSS.

Utilization of DFIG-based wind model for robust damping of the low frequency oscillations in a single SG connected to an infinite bus

“…The GSC converter maintains a constant DC link via v dg and maintains the terminal voltage via v qg . In the GSC controller, the q-axis of the reference frame aligns with the coupling point voltage, such that v dg = 0 in the power equation (10); this results in decoupled control. The following equations represent the GSC inner and outer controller dynamics: (12) The electrical torque of both generators and the input torque of the DFIG are expressed as follows:…”

“…The design of the feedback signal was influenced by several important factors, including the facts that (1) wind speed is highly changeable with respect to atmospheric conditions and (2) modes that are in close proximity have a significant influence on each other. Because the assessed system has a dominant mode with two closely proximate modes, all of the affected modes were considered in designing robust signals, with the specific objective of finding a feedback signal that improved the damping of 9,10 . Line current, line power, and rotor slip were assessed as candidate feedback control input signals (FCISs) (Figure 8).…”

“…1. P g = 0.9 pu: Signal s m has the highest residue, which corresponds to 9,10 . Although the residue of 7,8 for this signal is reasonably high, that of 13,14 is quite low; therefore, a controller primarily designed to improve the damping of 9,10 will affect 7,8 , but not 13,14 .…”

A Novel Reactive Power Optimization in Distribution Network Based on Typical Scenarios Partitioning and Load Distribution Matching Method

“…Step 4: Calculate the entropy of each evaluation index and the corresponding entropy weight according to Equation (16) and Equation (17) respectively.…”

Research on the stability of Multi-DGs system

“…While the oscillation mode is strongly related to the wind turbines, the oscillation of the system is restrained. But when the oscillation mode is strongly related to the synchronous generators, the damping of the system is practically unaffected [9]. Literature [10,11] considered that the wind load has little effect on the damping when the wind power ratio is about 16 %; after the introduction of PSS control unit, the wind farm composed of double fed induction generators (DFIG) can improve system damping, and the improvement degree for the damping is determined by the operation state of DFIG and the active power output.…”