Frequency Domain Aspects of Electromagnetic Transient Analysis of Power Systems

The electromagnetic transient (EMT) response of a power system can be determined either by time-domain (TD) or by frequency-domain (FD) methods. This chapter deals with those aspects of frequency domain analysis and of digital signal processing that have become essential for the analysis of transients in modern power systems. It provides a brief review of basic concepts of FD methods. Continuous-time Fourier analysis is introduced as an extension of phasor analysis which is more familiar to power engineers. The chapter presents the basic differences between continuous-time and discrete-time Fourier analysis. Of special interest in the chapter are: (1) the effect of aliasing, (2) the sampling theorem and (3) the principle of conservation of information. The chapter also provides a brief overview of multirate transient analysis methods based on the discrete Fourier transform (DFT) and the numerical Laplace transform (NLT).