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Schematic-Doubly Fed Machine based Type 3 Wind Turbine System
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This paper focuses on modeling Type 3 (Doubly Fed Induction Generators based) wind generation systems in the Real Time Digital Simulator (RTDS). It discusses the underlying converter and controller design algorithms and topologies. An alternative to the conventional Phase Locked Loop (PLL) tracking of rotor frequency is implemented. A comparative a...
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... and gear control. Type 3 systems use a DFIG connected with a back-to-back voltage sourced converter (VSC). Type 4 machines use a synchronous generator connected to a full scale VSC. The fact that the machine dynamics can be isolated partially (Type 3) and fully (Type 4) gives these systems a much better control on their operational rotor speeds. Fig. 1 shows the basic schematic of a Type 3 system with corresponding controllers. Grid side controller regulates the power being imported or exported from the Rotor side circuit. DC Regulator maintains a constant DC link voltage by regulating the output power reference of the Grid side controller. Rotor side controller tracks the maximum ...
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... r - l r . The output ctnrents have the same nature as the output currents from the one-machine model. Comparing the output currents from Fig. 7 with Fig. 17, the only difference is that the switching harmonics are also included. This validates that the aggregated and switching model behave similarly. The aggregated model will be validated in Section ...
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... single generator is not a very strong source to feed the fault currents. Since, the model is only one generator rated at 1.678MW, its contribution to the fault current is not significant. However, at the collector bus (22kV), much closer resemblance to this behavior is noticed (Fig. 10), as the fault is closer. The response at 230kV terminals for a 10-machine aggregated model (Fig. 11) resembles very closely to the field event response. Hence, the model is considered ...
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... strong source to feed the fault currents. Since, the model is only one generator rated at 1.678MW, its contribution to the fault current is not significant. However, at the collector bus (22kV), much closer resemblance to this behavior is noticed (Fig. 10), as the fault is closer. The response at 230kV terminals for a 10-machine aggregated model (Fig. 11) resembles very closely to the field event response. Hence, the model is considered ...
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... the plots for machine torque, rotor speed, DC bus voltage and reference tracking for grid side and rotor side are presented. Power output and its variation with speed has already been presented in Section V. Fig. 15 shows that the DC voltage regulator is tracking the reference voltages properly. Crowbar shorts the rotor terminals or the DC link capacitor via an external resistor. This is done to dump all the extra energy stored in the machine to resistors during voltage dips and faults. In this case, crowbar has been disabled to show the unbiased ...
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Citations
... It still captures the dynamics that impact relay response. The wind farm model used in this paper is described and validated for its basic fault behavior introduced in [3]. The discussion in [3] includes development of an aggregrate model to explore the impacts of using one large equivalent wind turbine model to represent a larger wind farm. ...
... The wind farm model used in this paper is described and validated for its basic fault behavior introduced in [3]. The discussion in [3] includes development of an aggregrate model to explore the impacts of using one large equivalent wind turbine model to represent a larger wind farm. Here, the model is utilized in a test network with a 230kV transmission line as shown in Fig. 2 ...
This paper analyzes the response of conventional protection schemes (Line current Differential and Mho Distance elements) and the supervisory elements associated with those protective elements in commercial relays for Type 3 (Doubly Fed Induction Generator based) grid integrated wind farms. The response of line protection elements and their supervisory elements are analyzed using real time by hardware-in-the-loop
simulation and differences from the behavior in case of conventional power systems are pointed. Faults are analyzed from the relay‘s perspective and the observed behavior is elaborated upon. Challenges associated in using sequence components and relay sensitivity are discussed.