In article , Josepi wrote:
I haven't seen a big box store or a grocery store, that uses fluorescents,
built in the last twenty years.
They all used HID lighting of some type. Of course they are even worse for
third harmonic content than CFLs.

People do not like the flicker of fluorescents, as it irritates the nervous
system but I am not sure the HID lighting is any better for persistence of
light. Count the number of fights in the grocery store and compare...LOL

HPS is much worse in that area. And fluorescent with electronic
ballasts have close to no flicker at all at frequencies related to the
power line.

Third harmonics take a special winding design to reduce the passing of third
harmonics to the generating source. Usually use of a zig-zag secondary
winding causes cancellation of any balanced multi-phase third harmonics.
This, in effect causes two phases to subtract their in phase components. In
a three pahse system third harmonics are typically all in phase between all
phases.

Neutral reactors are typically used in large tranformers and consist of a
large air core reactor. These reduce fault current to manageable levels but
convert many third harmonic currents into voltage problems which radiate the
problem to the rest of the system loads.

We ran into some interesting concepts with this on 100MVA transformer
voltage sensing. If the third harmonic crosses zero exactly the same time as
the fundamental the peak of the waveform is higher. If the third harmonic is
phase leading it lowers the peak of the fundamental.

How is the fundamental changed by presence of a harmonic?

This can play havoc
with a lot of sensing equipment without massive filters. We leave this
problem with the grid delivery system people to replace every $5M-$20M
transformer in their system. Cheaper lighting? You bet.

I have seen the current waveforms of CFLs, even in my own experience.
Those spikes are drawing current at the time the line voltage peaks, not
leading the peak of line voltage by a lot.

Also, even a low power factor CFL draws significantly less current than
the incandescent it replaces.

- Don Klipstein )