Speaker: Kalyani Mandadi (EE11D007)
Guide: Dr. B. Kalyan Kumar
Inter-area oscillations in power systems needs to be monitored and preventive measure should be taken which otherwise could lead to grid instability. Inter-area oscillations can be identified by analyzing the signals that are obtained from phasor measurement units (PMUs) placed at different locations in a system. Digital filter banks can be used for decomposing PMU signals into monocomponent signals for identification of inter-area oscillation frequencies. In the present work, filter bank designed with narrow-band linear phase finite impulse response (FIR) filters based on Zolotarev polynomials are used for decomposing the PMU signals. Signal decomposition using Zolotarev polynomials is preferred as this decomposition does not need any synthesis filters for reconstructing the signal. The sum of decomposed signals of the analysis filters is the delayed replica of the input signal. A narrow bandwidth of 0.1 Hz is achieved in the frequency range of 0 to 1 Hz with Zolotarev polynomial based filter bank (ZPBFB). Modal frequency and damping are then obtained by applying eigen realization algorithm (ERA) to monocomponent signals. The performance of the proposed method is compared with cosine modulated filter bank (CMFB). The robustness of the proposed method to white Gaussian noise is demonstrated using Monte Carlo simulations on the synthetic signal. The proposed Zolotarev polynomial based filter bank is validated on two-area test system and 16-machine, 68-bus system and the detailed simulation results are discussed. The efficacy of the proposed method is also demonstrated on three real time signals recorded by wide area frequency measurement system (WAFMS) at 3 locations in India on November 30, 2011.