Transient detection in phasor measurement units with kalman filtering

This paper presents a method based on the use of the residual of an Extended Kalman filter for step transient detection in phasor measurement units. The residual in a Kalman filter, defined as the difference between the measurement and the estimation, is close to zero when the signal is in stationary state but presents a significant increase at the beginning of a sudden change, when a large mismatch appears between the measurement and the estimation. Comparing the instantaneous magnitude of the residual with an adequate detection threshold, a step transient can be detected in the input signal. The paper studies the performance of the method in the detection of step transients in magnitude and phase angle, power swings, high-frequency transients and transient harmonic distortion in power system networks.