Effect of Embedded Induction Generators on Short-Circuit Detection

Author(s):  
Pieter Vermeyen ◽  
Johan Driesen ◽  
Ronnie Belmans ◽  
Daniel Van Dommelen
Author(s):  
Maruf A. Aminu

This paper is presented in an attempt to validate the dynamic response of a microgrid to line-to-line short circuit. The microgrid components include two identical Wind Turbine Generators (WTGs) tied to a 100MVA, 13.8kV utility via a Point of Common Coupling (PCC). The utility-microgrid testbed is modeled in SIMPOWERSystems® using two Doubly-Fed Induction Generators (DFIGs) in the microgrid side. While in islanded operating mode, line-to-line short circuit fault is applied at 6.0s and withdrawn at 8.0s, obtaining a 50.0s dynamic response of the system for different fault locations, under voltage and reactive power control regimes of the wind turbine controller. For measurement purpose, the absolute value of the stator complex voltage is transformed to  reference frame. Bidirectional power flow between the two feeders is established in the study. The study also confirms that the microgrid composed of DFIGs offer reactive power management capability, particularly by presenting superior performance when stressed under Q control regime than under V control regime. Finally, the response of the testbed to line-to-line short circuit has been validated and shown to be consistent with established short circuit theory.


Energies ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 4361 ◽  
Author(s):  
Dong Wang ◽  
Yunhui Huang ◽  
Min Liao ◽  
Guorong Zhu ◽  
Xiangtian Deng

Recent works have shown that phase-locked loop (PLL) synchronized wind turbines (WTs) suffer stability issues when integrated into weak grids. However, most of the current studies are limited to a single machine case, the interactions among the WTs are usually overlooked. This paper studies the stability of multiple doubly-fed induction generators (DFIGs) that are connected in parallel to a weak AC grid. A state space model of a two-DFIG system is firstly presented. Subsequently, eigenvalue sensitivity analysis shows that instability can occur at low short-circuit ratio (SCR) or heavy loading conditions. Meanwhile, participation factor analysis implies that the unstable mode is primarily induced by the interactions between the PLLs of the two WTs. Further, to make out how the PLLs interact to cause instability, a reduced-order model is proposed for analysis simplicity, and an explanation in terms of transfer function residue is given for illustration. Detailed model-based time domain simulations are conducted to validate the analyses’ results.


2002 ◽  
Vol 26 (3) ◽  
pp. 171-188 ◽  
Author(s):  
Vladislav Akhmatov

This article describes the second part of a larger investigation of dynamic interaction between variable-speed wind turbines equipped with doubly-fed induction generators (DFIG) and the power grid. A simulation model is applied for dynamic stability investigations, with the entire power grid subjected to a short-circuit fault. During the grid disturbances, the DFIG converter is found to be the most sensitive part of the wind turbine. Therefore the electrical currents are determined using the transient generator model. The converter action is crucial for wind turbine operation associated with such disturbances, especially regarding tripping or uninterrupted operation.


2007 ◽  
Vol 22 (3) ◽  
pp. 1965-1971 ◽  
Author(s):  
T. Sulawa ◽  
Z. Zabar ◽  
D. Czarkowski ◽  
Y. TenAmi ◽  
L. Birenbaum ◽  
...  

2003 ◽  
Vol 27 (2) ◽  
pp. 79-91 ◽  
Author(s):  
Vladislav Akhmatov

A model of the back-to-back converter is set up and implemented in the simulation tool PSS/E as a user-developed model. This model is applied with that of the doubly-fed induction generator (DFIG), described in previous parts of this work [parts II and I]. The latter models variable-speed wind turbines in power stability investigations. Subjected to a short circuit fault, there will be a risk of converter blocking, followed by tripping of the wind turbine [1, 3]. The main reasons of blocking are over-current in the rotor converter and over-voltage in the dc-link. The DFIG model, with representation of the back-to-back converter, results in (a) more accurate replication of the current in the rotor converter and (b) improved computation of the dc-link voltage. These improvements are compared with the model with representation of the rotor converter only. Hence, the DFIG model with representation of the back-to-back converters might be preferred, in practical investigations of power system stability, to models with representation of the rotor converter only.


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