Understanding the Unbalanced-Voltage Problem in Wind Turbine Generation

Research output: Contribution to conferencePaper


Most wind turbines are equipped with line-connected induction generators. Induction generators are very attractive as wind turbine generators due to their low cost, ruggedness, and the need for little or no maintenance. At constant frequency, the induction generator operates in a small range of speeds and, therefore, it operates with a small range of slips with respect to synchronous speed.Compared to a synchronous generator, an induction generator provides lower stiffness, thus alleviating the mechanical stress. In a weak power system network, an unbalanced load at the distribution lines can cause unbalanced voltage conditions. If an induction generator is connected to an unbalanced voltage, the resulting stator current will be unbalanced. The unbalanced current creates unequalheating (hot spots) on the stator winding. The heat may increase the winding temperature, which degrades the insulation of the winding, i.e., the life expectancy of the winding. Unbalanced currents also create torque pulsation on the shaft resulting in audible noise and extra mechanical stress. This paper explores the unbalanced voltage problem in induction generator. The levels of unbalance andthe loads are varied. Experimental and predicted results are presented in this paper.
Original languageAmerican English
Number of pages9
StatePublished - 2000
Event1999 IEEE Industry Applications Society Annual Meeting - Phoenix, Arizona
Duration: 3 Oct 19997 Oct 1999


Conference1999 IEEE Industry Applications Society Annual Meeting
CityPhoenix, Arizona

NREL Publication Number

  • NREL/CP-500-26338


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