A new algorithm for voltage sag detection

Voltage sags is a common power system disturbance, usually associated with power system faults. Therefore the effective detection of voltage sag event is an important issue for voltage sag analysis and mitigation. There are several detection methods for voltage sags such as RMS voltage detection, peak voltage detection, and Fourier transform methods. The problem with these methods is that they use a windowing technique and can therefore be too slow when applied to detect voltages sags for mitigation since they use historical value, not instantaneous value which may lead to long detection time when voltage sag has occurred. This paper presents a new algorithm for voltage sag detection. The algorithm can extract a single non-stationary sinusoidal signal out of a given multi-component input signal. The algorithm is capable of estimating the amplitude, phase and frequency of an input signal in real-time. It is compared to other methods of sag detection.