Power Quality, Harmonics, Mitigation etc.

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matthew.schenck.12

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I had a couple of Amprobe DM III’s that I have used over the years for load studies so that I can size a generator for residential loads.

I have upgraded to a Fluke 1738 and realized that hi it is severely underutilized in that role.

I would be interested in understanding from somebody that may have experience in the mitigation of power quality issues how you would approach a company and offer your services. In other words would you go up to them and explain power factor, and reactance, and how it’s costing them money?

I would also like to understand if there is a payback on the mitigation equipment and how long that is. Can the payback be in utility cost savings or is it typically a combination of utility cost savings and increased lifespan of the equipment?

Thanks
 
matthew.schenck.12 said:
I had a couple of Amprobe DM III’s that I have used over the years for load studies so that I can size a generator for residential loads.

I have upgraded to a Fluke 1738 and realized that hi it is severely underutilized in that role.

I would be interested in understanding from somebody that may have experience in the mitigation of power quality issues how you would approach a company and offer your services. In other words would you go up to them and explain power factor, and reactance, and how it’s costing them money?

I would also like to understand if there is a payback on the mitigation equipment and how long that is. Can the payback be in utility cost savings or is it typically a combination of utility cost savings and increased lifespan of the equipment?

Thanks
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I like to approach PQ as a cost savings and preventive maintenance service. Equipment life can be extended and performance can be optimized. Offering a free basic inspection can get your foot in the door to uncover issues. There is always something wrong that you can find with an installation IMO.
 
Depends on whAt you mean by “PQ”. There is a lot hiding under that name.

Harmonics are by far the least understood and most blamed. Most of it is pure BS. IEEE 519 is often cited but it’s a standard for utilities at the POD, not anybody else. But it’s instructive in understanding what is probably the #1 mistake made by amateurs. First do current harmonics cause voltage harmonics or vice versa? The answer is current harmonics cause voltage harmonics. When different frequencies coincide if the resulting peak current exceeds transformer capacity or other large impedances it causes voltage to dip. This drop in voltage can cause severe problems with loads as well as heating transformers from the overloaded condition and causing major issues with capacitors. But as long as the power distribution system is not near its limits harmonics are a nonissue. This is why IEEE 519 places tight limits on voltage THD and tight limits on current TDD which ratios harmonics against transformer capacity. So amateurs/scammers will show you some very ugly current THD from an electronic power device and tell a huge lie about how bad this is when voltage THD is almost always nonexistent. All that this ultimately means is that when you get close to system capacity rather than just the inevitable problems with voltage sags caused by switching loads, harmonics potentially trigger capacity issues at a somewhat smaller load,

Sags and swells are important for remote sites or when utility bus is weak, This is a much more common issue causing lots of issues.

Surges are often caused by switching of inductive loads abc this can be extremely damaging. And they are far more common than lightning. Surge protection can mitigate or eliminate this if done properly.

As far as money usually the solutions are inexpensive but the diagnosis is where the money is at. These are typically some of the most difficult problems to solve in distribution,
 
EC&M magazine has a monthly column on power quality, case studies. A review of back issues would be a good place to start.
 
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