Sensitivity of low voltage consumer equipment to voltage sags

Voltage sag is an issue that is becoming increasingly important to electricity consumers at all level of usage. These result from with increasing use of electronic equipment in several sectors for the reason to improve energy efficiency and performance. Customer´s included in low voltage environments mostly are sectors: Commercial, Residential and Light industrial. In these sectors many found equipments such as television, microwave ovens, personal computers, printer, lighting, heating ventilation air conditioners, motor contactor etc. Using with high efficiency fluorescent lighting with electronic ballast, single phase switch mode power supplies for computers, contactor for protecting motor from suddenly restarting when the voltage is recovered. These equipments are characterized as highly susceptible to voltage sags. Voltage sags are most frequent among various types of power quality disturbance faced by many consumers. Source of voltage sags are generally caused by short circuit faults associated with equipment failures on the supplying power system. Voltage sags normally do not cause equipment damage, but it can easily disrupt the operation sensitive equipment. Effects produced by voltage sags are various generally depending on its characteristics and equipment. The magnitude and duration of the sags are commonly used to evaluate sensitivity of equipment. The other characteristic such as point on wave of voltage sag initiation is significance influence to be considered. This paper presents voltage sag tolerance levels curves of three equipments sensitive to sags namely; personal computers, contactors and lightings. A Schaffner “Profline2100” has used to generate voltage sags and testing to get sensitivity of the equipment.