Comparative characteristics of main methods for dynamic estimation of frequency and magnitude parameters in power systems

An accurate dynamic estimation of frequency and magnitude parameters (actual power-line frequency and actual power-line voltages or currents) is very important for different applications in power systems, such as frequency and magnitude relay protection, harmonics and quality of power in transient regimes, especially for local power systems with external UPS (uninterruptible power supply) synchronization (for example, by diesel-generator). Investigated methods and algorithms are modifications of OPD (orthogonal phasor decomposition) and IZC (integrating zero crossing) for frequency estimation and modifications of DFT (discrete Fourier transform) with interpolation in time or frequency domain, or alternatively, with pre-tuned prefilters, for magnitude (harmonics) estimation. Some aspects of choice and optimization of the above DSP (digital signal processing) methods and algorithms were described before in publications, but without comparison of their characteristics, which are the main subject of the proposed publication. Obtained simulation results can be used for improvement of chosen algorithms and their real time applications.