Voltage imbalance, also referred to as voltage unbalance, is an important power quality issue that can lead to significant operational problems in customer equipment. It occurs when the magnitudes or…
Voltage Unbalance White Papers
Power quality white papers on Voltage Unbalance.
20 white papers in Voltage Unbalance
Understanding IEEE 1159 Definitions
It is very important to have recommended guidelines and practices in place regarding power quality monitoring with the use of consistent terminology and definitions of power quality phenomena. This is…
Adjusting Waveform Capture Sampling Rates
Waveform capture is one of the most important data types available for PQ analysis. The sample-level data provides detailed information for voltage disturbances such as oscillatory transients, notches, sub-cycle overvoltages…
Four-Wire Delta Voltage Unbalance
Voltage unbalance in a four-wire or "high leg" delta can be tricky to measure. A 4-wire delta often involves unbalanced impedances, and phase shifts in the hot leg are common.…
Hidden Delta Voltage Unbalance
Voltage unbalance can cause severe heating in motors and large DC power converters. Although most voltage unbalance is caused by unequal loading among phases, shifts in voltage phase angle can…
Voltage Swell from Recloser Operation
A recloser is most associated with brief voltage interruptions, possibly followed by an extended outage if a fault cannot be cleared. Upstream customers experience voltage sag during the reclose attempts,…
Voltage Unbalance with Canvass
Voltages are rarely perfectly balanced in three-phase systems. Although small unbalances are not usually a problem, if this unbalance becomes too great then the unbalance can cause problems especially for…
Measuring Voltage Unbalance
Voltage unbalance can cause severe heating in motors and large DC power converters and an increase in harmonic currents. Fortunately unbalance is easy to measure with PMI recorders and ProVision…
