Implementation, Comparison and Application of an Average Simulation Model of a Wind Turbine Driven Doubly Fed Induction Generator

Lidula Widanagama Arachchige, Athula Rajapakse, Dharshana Muthumuni
2017 Energies  
Wind turbine driven doubly-fed induction generators (DFIGs) are widely used in the wind power industry. With the increasing penetration of wind farms, analysis of their effect on power systems has become a critical requirement. This paper presents the modeling of wind turbine driven DFIGs using the conventional vector controls in a detailed model of a DFIG that represents power electronics (PE) converters with device level models and proposes an average model eliminating the PE converters. The
more » ... SCAD/EMTDC™ (4.6) electromagnetic transient simulation software is used to develop the detailed and the proposing average model of a DFIG. The comparison of the two models reveals that the designed average DFIG model is adequate for simulating and analyzing most of the transient conditions. 2 of 25 where PE converters are modeled with device level details, in PSCAD/EMTDC is presented in [6]. It describes the simulation models of the machine, wind turbine and PE converter controls in detail, and presents performance of the developed DFIG simulation model when connected to a simple radial power system having a nonlinear load. A discussion on dynamic modeling of DFIG is presented in [7] with a focus on the machine and turbine modeling. The converter control is not properly discussed in [7]. It presents the use of crow-bar protection for the rotor side converter and illustrates the performance of the developed DFIG model under system faults. Many of the studies cited above need long duration simulations, especially when studying phenomena influenced by mechanical inertia and low frequency oscillations. When the detailed PE converter models are used in the DFIG model, EMT simulations takes considerable computing resources and time. This is cumbersome, if the simulations need to be repeated many times. In order to address this, an average model of a DFIG driven by a wind turbine is presented in [8]. The EMT simulation model of the power systems is developed using the Matlab (4) Simulink-based SimPowerSystems software. The paper discusses the modelling of the wind turbine and its operation in detail, while briefly stating how the average model of the converters developed. A different simplified transient model of a DFIG is used in [9] to study the inertia characteristics of a DFIG wind turbine under transient control. The paper analyzes the impact of DFIG wind turbine on the first-swing stability of synchronous generators using the simplified DFIG model, but its accuracy is not validated. This paper addresses the general lack of details of modeling wind turbine-driven DFIGs for EMT simulations, and the need for properly validated simplified models for long duration EMT simulations. This paper differs from the previous literature due to following features: the paper focuses more on the basis and details of converter controls, develops both detailed and average models of a DFIG, and extensively validates the developed average DFIG model against the detailed DFIG model. The limitations of the average DFIG model, which represents PE converters using controlled voltage and current sources, are also discussed. Finally, the application of both models in a medium voltage distribution network is demonstrated. Wind Turbine Driven DFIG Control In a DFIG, a wound rotor induction machine is used with the rotor winding being fed through partial-scale (only 25-30% of the generator capacity) back-to-back converters [3][4][5][6][7]. The stator is directly connected to the grid while the rotor is connected to the grid through power electronic converters. The block diagram of a typical configuration of the wind turbine driven DFIG is shown in Figure 1 .
doi:10.3390/en10111726 fatcat:gv3f5uafhvcvnnxh4uhwypaeia