Development of distributed relaying processor with digital filtering of fast sampled data

In order to cope with advanced relaying techniques, a multimicroprocessor-based digital relay was developed. The main features are distributed processing among five processors, 32-b floating-point operations, digital filtering of fast sampled data, and a personal computer based testing tool. Performance tests of this digital relay showed the following characteristics: (1) the error of any relaying element (distance, overcurrent and undervoltage) was less than 1%; (2) operating time was less than 20 ms when the processing interval was 1.67 ms; and (3) a single relaying processor had a computational capacity of six-phase (ground, short*4 steps*3 phases) distance relays based on differential equations, accompanying elements, and a self-diagnosis function in every processing interval.<
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