If you were to ask a handful of customers what they consider a ‘power surge’ to be, you would get a multitude of answers — anything from a lightning strike…
Voltage Unbalance White Papers
Power quality white papers on Voltage Unbalance.
22 white papers in Voltage Unbalance
Reverse Power Flow in Distribution Feeders
Most distribution feeders were planned around one-way power flow: from centralized generation, through substations and feeders, to customer loads. The rapid growth of Distributed Energy Resources (DERs) — rooftop solar,…
Understanding Load Diversity and Its Effect on Power Quality
Introduction Your home and the office building down the street both run on electricity from the same utility, but they don’t typically use it in the same way at the…
Understanding Voltage Phase Rotation in Three-Phase Systems
Three-phase power systems depend not only on equal voltages between phases but also on the order in which those phases reach their peaks — a property called phase rotation. Incorrect…
Analyzing Motor Startups with the Bolt
Induction motors are ever popular in today’s world and can be found in most areas of life — industrial, agricultural, and even residential settings. These motors can have high inrush…
Understanding Voltage Stability vs. Voltage Regulation
Voltage stability and voltage regulation are commonly confused concepts, particularly in the context of customer voltage complaints and power quality investigations. These two phenomena differ significantly in both cause and…
Introduction to Ferroresonance
Ferroresonance is a nonlinear electrical phenomenon that can damage transformers, surge arresters, cable insulation, and switchgear — and create dangerous backfeed voltages on conductors that should be de-energized. Although relatively…
Recognizing Transformer Energization in Power Quality Data
Transformer energization events occur frequently in electrical distribution systems and often appear in power quality recordings. These events can produce large transient currents and waveform distortions that may initially resemble…
Voltage Unbalance and Polyphase Induction Motors
While three-phase AC squirrel-cage motors have been around and reliable since 1889, courtesy of Mikhail Dolivo-Dobrovolsky, one issue that has plagued their operation and lifespan throughout the years has been…
Voltage Regulation: Standards-based Compliance
Voltage regulation—the ability to maintain steady‑state RMS voltage within acceptable bounds—affects equipment performance, protection, and customer experience. Distributed energy resources (DER) add complexity via bidirectional power flow and daytime voltage…
Voltage Unbalance Within PQ Canvass Compliance Reports
Power Monitors, Inc.'s PQ Canvass is a secure, cloud-based platform built for power-quality (PQ) analysis. PQ Canvass has a beta feature of automated "compliance reports" that transform data uploaded from…
Voltage Tug-of-War The Silent VFD Killer
The modern variable-speed drive (VFD) is a sophisticated power electronic system, yet the front end is still a deceptively simple six-pulse diode bridge. That simplicity means the rectifier has little…