METHOD AND DEVICE FOR DETECTION OF SUB-SYNCHRONOUS OSCILLATIONS IN A POWER SYSTEM

A method for detection of a sub-synchronous oscillation in a power system is provided wherein the following steps are performed: measuring of a three-phase measurement signal of an electric system value, analyzing the measurement signal to detect an oscillation component of the measurement signal having an oscillation frequency that is lower than a system frequency of the power system, deciding whether the detected oscillation component at the oscillation frequency qualifies as a sub-synchronous oscillation, and disconnecting a generator from the power system that might be affected by the sub-synchronous oscillation. [0002] In order to detect sub-synchronous oscillations with low computational effort and with a good accuracy, it is proposed that an amplitude of each phase of the oscillation component is being calculated and compared against a threshold, detecting a sub-synchronous oscillation when the threshold is being exceeded during a given time delay, and generating a fault signal if a sub-synchronous oscillation has been detected. [0003] Furthermore, a device is provided containing a processing unit to perform such a method.