The fast Hartley transform used in the analysis of electrical transients in power systems

Using the fast Harley transform in analyzing electrical transients in power systems is considered. Periodic and nonperiodic signals are studied. The fast Hartley transform (FHT) is a real transform which is very similar to the fast Fourier transform (FFT). The FHT has many of the useful properties of the FFT, however it is a purely real transformation, thereby yielding computational advantages. Several properties of the FHT when used in power systems are addressed, including representation of initial conditions, convolution properties and symmetries, filtering and windowing, aliasing errors in both the Hartley frequency and time domains, and certain properties related to time scaling and zero padding. Practical methodologies are presented for calculating electrical transients; these signals may occur in electric power systems due to nonperiodic phenomena such as switching surges and transformer inrush or to periodic phenomena such as those found in electronic power processing devices. The methodology presented is useful for power-quality assessment.