A Fault Equivalent Network Based Method for Calculating the Doubly Fed Wind Power Generator Short-circuit Currents |
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Authors: | Jing Ma Tianyi Huang Chang Liu Lvyi Sun James S Thorp |
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Affiliation: | 1. State Key Laboratory for Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing, China;2. Bradley Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA;3. Bradley Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA |
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Abstract: | Abstract—Current research on short-circuit currents of the doubly fed induction generator is all based on the traditional flux analysis theory. In this article, a novel method to calculate the doubly fed induction generator stator and rotor short-circuit currents is proposed based on the fault equivalent network. First, the fault network is decomposed into a no-fault (normal operation) network and a fault supplementary network. On this basis, considering the influence of the terminal voltage phase jump and the rotor-side converter control, from the perspective of function decoupling, the fault supplementary network is further decomposed into the stator-side fault supplementary network and the rotor-side fault supplementary network. Laplace transformation is then used to calculate the current additions of the two fault supplementary networks. Thus, the analytical expressions of all currents under the grid symmetrical and asymmetrical short circuit could be derived. Finally, both simulation and dynamic experiment results verify that the doubly fed induction generator short-circuit current expressions derived with the proposed method are correct, which facilitates the short-circuit current calculation and relay protection setting of a power grid with a doubly fed induction generator connection. |
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Keywords: | doubly fed induction generator terminal voltage phase jump rotor-side converter control stator-side fault supplementary network rotor-side fault supplementary network Laplace transformation grid symmetrical short circuit grid asymmetrical short circuit simulation experiment results dynamic experiment results |
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