Meaning
A short-duration reduction in root-mean-square voltage lasts from a fraction of a cycle to several seconds, caused by faults on the power system or the starting of heavy loads. Industrial facilities experience transient voltage sags when large electric motors draw high starting currents or when lightning strikes transmission lines. These sudden drops in electric potential disrupt the operation of sensitive electronic controllers and automated assembly systems.
Grid Interaction
Detecting and logging power disturbances requires specialized power quality monitors that measure voltage waveforms continuously. This tracking of transient voltage sags occurs during plant operations to correlate voltage drops with the start of heavy machinery or external grid events. Conducting audits of the electrical supply over several weeks provides the data needed to determine the average depth and duration of these events.
Equipment Sensitivity
Automated production lines are highly vulnerable to sudden decreases in voltage. When transient voltage sags occur, programmable logic controllers and variable frequency drives often trip to protect themselves. This protective action halts the entire manufacturing process, causing material wastage and requiring manual resets of the equipment.
Mitigation Strategy
Installing uninterruptible power supplies or active voltage conditioners isolates sensitive controls from fluctuations in the incoming power grid. This isolation protects the factory from costly downtime during minor grid disturbances.
