DBSCAN-based coherency identification of generators using complex wavelet transform

• Main Authors: Ajeet Kumar Singh, Manoj Fozdar
• Format: Article
• Language: English
• Published: Wiley 2019-05-01
• Series: The Journal of Engineering
• Subjects: matrix algebra; power system measurement; oscillations; power system stability; electric generators; rotors; power system transient stability; pattern clustering; wavelet transforms; power system control; complex wavelet; multimachine power system; instantaneous phase difference; phase difference matrix; relative phase difference; dominant frequency components; oscillating rotor angles; higher dimensional space; coherent generators; noise algorithm; new england 39-bus test system; ieee 145-bus test system
• Online Access: https://digital-library.theiet.org/content/journals/10.1049/joe.2018.9239
• ISSN: 2051-3305

The coherency of generators in a multi-machine power system is identified by determining the instantaneous phase difference between their rotor angles using a complex wavelet transform. A new phase difference matrix is proposed that represents the relative phase difference between the dominant frequency components of each pair of oscillating rotor angles and maps it into a higher dimensional space where data points corresponding to coherent generators lie in proximity. Next, density-based spatial clustering of applications with noise (DBSCAN) algorithm is used for automated grouping of coherent generators. A new objective function is proposed for the determination of control parameters of the clustering algorithm. The proposed approach is tested on the New England (NE) 39-bus test system and IEEE 145-bus test system.