[R-390] Voltage Reduction Scheme

[Tisha Hayes]

Quote: "The addition of an external bucking transformer comes to mind as a
wise thing with the power companies pushing line voltages up into the near
130VAC range to keep from replacing all that wire to carry the load."

You will see in the immediate future, electrical utilities being pressured
to optimize their systems and to place their tap-changers on an active
control system for voltage reduction. Many of the utilities that I am
working with today are trying to actively manage their voltage distribution
schemes. The thought once was to figure out the maximum sag that would be
present on a distribution line and to set the substation tap changers to a
semi-fixed position to avoid a brownout condition. Now the emphasis is on
finer control of distribution voltages so you will see less of a min/max
change in line voltages.

The same thing is true of capacitor banks to manage reactive power. Many
were on a TOD (time of day) setting, now they are being moved to active
control tied into the power factor at the distribution substation.
Transmission and generation facilities want the distribution (your local
electric utility) to fit into a narrower range of power-factor values with
penalties if it is too far off.

I have been involved in a few analyses of distribution system losses. In
some cases they can be as high as 8-12%. For a utility to reduce it down to
4-6% can save them millions of dollars in a year. Moving to active control
ends up being something that has a ROI (return on investment) of 2-3 years.
That also goes back to feeder monitoring so when they do need to make line
change-outs on the distribution system they are working on circuits with the
greatest % of losses and the utility can see the greatest bang for the buck.

That is where the communications part of my job comes in. Something that
they once were happy to monitor once or twice a day they now want updated
every few minutes. It requires fiber-optic communications networks, IEC61850
substation networks and Ethernet speed radio systems.
-- 
Ms. Tisha Hayes/ AA4HA
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"I'll be a diode, cathode, electrode
Overload, generator, oscillator
Make a circuit with me." -- The Polecats