Subspace-Driven Output-Only Based Change-Point Detection in Power Systems

The use of phasor measurement units (PMU) has enabled monitoring the power system dynamics online. There are many PMUs installed, which will give a comprehensive view in real or near real time of the entire system. In general, there are many operating conditions of power systems, which requires different tools to analyze the synchrophasor data provided by PMUs. Changes in power system monitoring must be detected as quickly as possible, so that the system operators can choose a different tool for data analysis. Therefore, in this paper, changes in the working conditions of the power system are detected using a subspace state-space based change-point detection method. The detection algorithm proposed in this paper is sequential detection, which aims at both detection accuracy and detection speed. We have tested our proposed algorithm to detect many various kinds of changes in power system operations and verified that the algorithm is able to detect changes successfully, including very small ones in the system such as the low-amplitude forced oscillations buried in the system's ambient conditions in a real-time manner. The algorithm is tested in a set of real-world data to show its practical usage in large systems with imperfect data.