PERFORMANCE EVALUATION OF SELECTED BRANDS OF AUTOMATIC VOLTAGE REGULATOR

Abstract

Automatic Voltage Regulators (AVRs) are intended to regulate the supply voltage and maintain a constant output voltage. In this paper, five AVR brands with 2 kVA rating namely; Prag, QASA, Century, BlueGate and Mercury sold in the Nigerian market were selected and tested for their output performance under normal, varying load and voltage conditions. Under normal supply condition, all the brands operated satisfactorily within their rated characteristics. During the varying load test, Century recorded the lowest load regulation of 3.16% for 1.5 kW load while Mercury has the highest at 10.94%. In the varying voltage test, the cut-off voltage occurred at approximately 40V, 70V, 50V, 70V and 90V for Prag, QASA, Century, BlueGate and, Mercury respectively. The output performance showed that Century, QASA and Mercury AVRs operated moderately well at a maximum load of 1.5 kW with output performance of 92%, 91%, and 91% respectively however; Prag and BlueGate were significantly low at 84% and 83%. Two key factors recommended for the selection of AVRs for domestic or commercial use are; the wattage rating of the load(s) to be connected and the supply voltage in the area. Century, QASA, BlueGate and Mercury AVRs are recommended for use in areas having low voltage supply range 50V–110V but with a maximum loading of 1.5 kW while Prag is suggested for areas with extremely low voltage (40V) but the load should not exceed 1 kW. Furthermore, the AVR power rating (in kW) should be at least 25–30% higher than the total wattage rating of the loads to be connected.