A transputer-based waveform synthesizer for protection relay test and parameter estimation applications

Power system faults can give rise to highly complex transient voltage and current waveforms, particularly during the periods immediately following the faults. Modern microprocessor-based protection relays can in principle respond intelligently to such input signals. This gives rise to the need for test equipment with the capability to evaluate protection relay performance for representative waveform data recorded for actual field conditions, or obtained alternatively by simulation using software packages such as the Electromagnetic Transients Program (EMTP). This paper describes a computer-based, multiphase, arbitrary waveform synthesizer for protection relay test applications. The system distinguishes itself from other such arrangements in that it features a highly programmable and versatile transputer-based digital to analog converter facility developed primarily with the view to obtain optimized performance for protection test applications