NOVEL MICROPROCESSOR-BASED NEGATIVE PHASE SEQUENCE RELAY AND METER

Microprocessor application in relaying and condition monitoring techno logy is becoming increasingly popular. In this paper, a novel micropro cessor based negative phase sequence (NPS) current detector for motor condition monitoring and relaying for motor/generator protection is de veloped. The proposed meter eliminates the need of a negative phase se quence filter and does not require complicated digital signal processi ng techniques. Instead it uses a phase sensitive rectifier. A prototyp e based on Intel's 8085 A microprocessor was built and rested. Complet e circuitry, main and interrupt software flowcharts are provided. Resu lts show the proposed NPS relay and meter can provide a high degree of accuracy and satisfactory results. Copyright (C) 1996 Elsevier Scienc e Ltd.