Microprocessor system for measuring frequency spectra and computing transient responses of a power apparatus

The automatic amplitude and phase measuring system is constituted by a low-voltage sine-wave signal generator with synthesised frequencies in the 10 Hz¿11 MHz band, an RMS voltmeter, a phase detector, and an 8-bit microprocessor with 16 Kbyte memory,. The design of the phase detector has been worked up in an original manner. The microcomputer automates the generation of input signals and permits acquisition of frequency spectrum amplitude and phase data, which are used to evaluate the parameters of a digital simulator. The simulator, having the structure of a transversal digital filter, allows the computation of the transient responses to any input waveforms. The constructed microprocessor system can be used for low voltage measurements on apparatus of any type and power for frequencies up to 5 MHz. The measuring devices were used to measure some frequency spectra of a 20 MVA three-phase transformer and for computing time responses to impulse waveforms. The computed results are in closer agreement with the measured ones.