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Document Type

Thesis - University Access Only

Award Date


Degree Name

Master of Science (MS)

Department / School

Electrical Engineering and Computer Science

First Advisor

Reinaldo Tonkoski


Distribution systems are typically designed to operate in a single power flow direction: from the substation to the load. However, the integration of distributed energy resources, such as wind energy systems, can change the direction of the power flow, leading to a voltage rise in the feeder. In systems with high penetration of wind, overvoltage can occur, which is one of the major concerns regarding power quality issues. Among different solution to overvoltage problem, active power curtailment is a very attractive solution since only small adjustments in the controllers are necessary for implementing this technique and is activated only when needed. In wind energy systems, this can be achieved by adjusting the pitch angle of the wind turbine. The objective of this thesis was to develop an active power curtailment strategy for small wind turbines to prevent overvoltage by controlling the pitch angle of the turbine blades. An equation was developed relating power produced by wind turbine and the blade pitch angle using maximum power point tracking control. The required blade pitch angle was calculated by using droop based active power curtailment. The developed control strategy was validated by a real time simulation of a rural feeder model implemented in MATLAB/Simulink. The simulation was implemented by considering two cases, one with base case and another with the active power curtailment with blade pitch control. These two cases were used to validate the proposed approach by simulating the model in short period of 24 hours and long period of one year. The results indicated that the approach can help maintain voltages at the points of connection within limits the overvoltage in the system and provided continuous power input to the system. This shows that active power curtailment using blade pitch-angle control can be used to prevent overvoltage in low voltage rural distribution networks for small to medium size windturbines with pitch control.

Library of Congress Subject Headings

Wind power
Overvoltage -- Prevention
Low voltage system


Includes bibliographical references (pages 89-91)



Number of Pages



South Dakota State University


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