Interharmonics are one of the most complex power quality quantities to measure and analyze. The concepts are advanced, the terminology is confusing, the raw data is voluminous, and the interpretation…
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83 results by Chris Mullins — Clear
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…
Transient Capture vs. Waveform Capture
Most PMI recorders include waveform capture, and the Revolution optionally includes a high-speed microsecond-level transient capture system. Although PMI waveform capture and transient capture seem very similar on the surface,…
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,…
Overcurrent Protection with Fused Leads
PMI offers a fused voltage lead kit for increased safety with the Revolution and Eagle power recorders. Although not required to meet UL safety standards with these recorders, the fused…
Understanding PMI Data Record Types – Part 3
The job of any power monitor is to record all interesting data, and leave unrecorded the vast majority of boring, unremarkable data. The tricky part for a monitor is deciding…
Using Scale Factors for PT/CT Ratios & Per-Unit Analysis in ProVision
Raw voltage, current, and power signals applied to a PQ recorder are often scaled versions of the true data under question. Transducers such as PTs and CTs step the voltage…
Voltage Regulation Analysis With Daily Profiles
If there were no variations in distribution load, system voltage regulation would be a simple task. But Ohm’s law dictates that a change in load produces a change in delivered…
Understanding PMI Data Record Types – Part 2
The job of any power monitor is to record all interesting data, and leave unrecorded the vast majority of boring, unremarkable data. The tricky part for a monitor is deciding…
Getting Started with Stripchart Analysis in ProVision
Stripchart data, also known as trend or interval data, is often the most important information in a power quality recording. The bulk of the recorder memory is dedicated to it,…
Understanding PMI Data Record Types – Part 1
The job of any power monitor is to record all interesting data and leave unrecorded the vast majority of boring, unremarkable data. The tricky part for a monitor is deciding…
Photovoltaic Monitoring Setup Recommendations
Photovoltaic (PV) systems generate new power quality and even basic grid stability challenges. The rapid deployment of PV generation requires comprehensive monitoring to help understand and quantify the impacts on…