The Solid State Transformer (SST) may be a groundbreaking innovation in electric distribution, replacing the century-old "pole pig" with a modern, active power supply architecture. Although still in the early…
White Papers
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51 results by Cowles Andrus III — Clear
Linear vs Non-Linear Loads
In this white paper I define linear and non-linear loads, describe what characteristics cause a load to be linear or nonlinear, and show how these load types can affect the…
Tips on Transformer K-factor
Transformer loading is ultimately limited by internal heating caused by load current flow. Some heating is caused by resistive losses in the transformer winding. Another important heating source is eddy…
Skin and Proximity Effect on Power Transmission
This paper describes what skin effect and proximity effect are, how they influence electric power transmission, and what steps are taken to reduce their losses.
UPS Power Quality Case Study
In this white paper, power quality issues that can result from an Uninterruptible Power Supply (UPS) are discussed. Covered are the basic operational concepts of the more popular types of…
Zero Sequence Harmonics
In this whitepaper, I will discuss zero sequence harmonics: what they are, how they are created, and what issues they present to distribution systems and power quality. Zero sequence harmonics…
Low-Energy Lighting and Power Quality
In this paper I reviewed the effects that Compact Fluorescent Lamps (CFL), Light Emitting Diodes (LED), and halogen lighting have on power quality. The CFLs and some LEDs present a…
Case Study of Portable Generator Power Quality
In this paper, power quality data taken from several different generators is reviewed. Standby and portable generators can be very important for backing up essential systems when utility power isn’t…
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…
Recording Interharmonics with the Revolution
Interharmonics are on the rise because of large non-linear loads and sources being introduced to the distribution network, in particular large Variable Frequency Drives (VFDs) and inverters for distributed generation.…
Electrical Undervoltage and Power Quality
In this whitepaper, the term undervoltage is explained, some typical causes of undervoltages are given, and the effects of undervoltage on customer loads is described. IEEE 1159-2009, IEEE Recommended Practice…
Data Collection During Quick Fluctuations in Line Voltage
One of the most useful methods for examining specific power quality activity is through filtered predesignated reports. At PMI we've achieved this with our "Significant Change Report." The primary use…