Transient Stability Enhancement of Wind Generator by a New Logical Pitch Controller

Abstract

In this paper, a new logical pitch controller equipped with fuzzy logic controller (FLC) has been proposed which can enhance the transient performance of wind turbine generator system (WTGS) when severe network disturbances occur in power system. Moreover, it can maintain the output power at rated level when wind speed is over the rated speed. Before transient stability analysis, it is necessary to determine initial values of WTGS connecting with the external network. In this paper, the initial value calculation method of WTGS is discussed also at different windy conditions. Finally, in order to evaluate the effectiveness of the proposed controller for transient stability, simulations have been carried out for severe network disturbances and windy conditions. From the simulation results it is seen that the proposed controller can enhance the transient stability of wind generator at any network, fault or windy condition as well as maintain output power of wind generator at rated level when wind speed is over the rated speed.The model system used for simulation of transient stability is shown in Fig. 1. The main purpose of using the pitch controller with wind turbine is to maintain a constant output power at the terminal of the induction generator (IG) when wind speed is over the rated speed. The proposed controller as shown in Fig. 2 can serve this purpose well. Moreover, it can also enhance the transient stability of induction generator. For the robustness of the pitch controller it is necessary to sense the terminal voltage of IG as the controller input. If the IG rotor speed increases to threshold value, i.e. 3% increase from its rated speed, the controller works in speed control mode, where W THR IG is the threshold value. Pitch controller operating status will be determined by a status gain whose input will be the output of logical comparator. The performance of the proposed pitch controller equipped with FLC is compared to that of equipped with PI controller. The power and speed response of IG after a 3LG fault in power system are shown in Fig. 3 and Fig. 4 respectively. It is clear Mohd. Hasan Ali * MemberRion Takahashi * MemberToshiaki Murata * MemberJunji Tamura * MemberIn order to investigate the impacts of the integration of wind farms into utilities networks, transient stability should be analyzed before connecting wind turbine generator system (WTGS) to the power system. In this paper, a new logical pitch controller equipped with fuzzy logic controller (FLC) has been proposed, which can enhance the transient performance of WTGS during severe network disturbances. Moreover, it can maintain the output power at rated level when wind speed is over the rated speed. Before transient stability analysis, it is necessary to determine initial values of WTGS connected to the external network. In this paper, the initial value calculation method of WTGS is discussed at different wind conditions. Finally, in order to evaluate the effectiveness of the proposed controller in improving the transient stability, simul...

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Analysis and Modeling of Advanced Power Control and Protection Requirements for Integrating Renewable Energy Sources in Smart Grid,

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