Adjustable speed drives susceptibility to voltage sag

Abstract

Voltage sags are probably the most important power quality problems affecting industrial and large commercial customers. These events are usually associated with a fault somewhere on the supplying power system. The interruptions occur when the faults is on the circuit supplying the customer. Voltage sags are much more common since they can be associated with faults remote from the customer. Voltage sags are caused by abrupt increases in loads such as short circuits or faults, motor starting, or electric heaters turning on, or they are caused by abrupt increases in source impedance, typically caused by a loose connection. Voltage sags are the most common power disturbance. Voltage sags are frequent cause of disrupted operations for application of ASD in industry. Programmable software, Schaffner Profline 2100 EMC used to generate the voltage sag. The equipment under test such as adjustable speed drive will be fed up with various depth and duration of sag. The characteristic of the equipment will be recorded .In other words this research bring to the study of voltage sag tolerance level, the effects and causes to the two above equipments and all the characteristic when they operate in sags condition. Mitigation method to deal with voltage sag is to be expected at the end of the project.