A novel procedure for real-time detection of inter-area oscillations

The paper presents a novel procedure for real-time detection of inter-area mode using distributed signals obtained by phasor measurement units (PMUs). Wide Area Control System signals could be intrinsically corrupted by noise and moreover characterized by data packets dropout due to transmission errors, buffer overflows and so on. In order to deal with the aforementioned troubles, an architecture which firstly performs a proper reconstruction technique, based upon a linear regression, and a digital filtering is proposed. The signals previously elaborated are fed through several windows of samples to the proposed measurement-based algorithm able to detect in real time electromechanical oscillations. It consists of a preliminary estimation of the electromechanical mode number by using Hankel Singular Value Decomposition (HSVD) and a successive application of the Variable Projection Algorithm (VarPro) to determine the damping and frequencies´ mode. Consequently, some control actions have to be implemented if any unstable mode is detected, in order to avoid the power system collapse. A numerical application based on Kundur´s 2-area test system confirms the potentiality of the proposed algorithm, comparing moreover its performances with those of other algorithms suitable for this kind of application.