When the grid frequency is constant all the ferroresonance circuits that can
blow up due to standing waves do it as they are each energized. If you vary
the frequency the ferroresonance parts will suddenly appear at random and
the grid would become very unstable. This sound like grid suicide. Many
pieces of equipment would not like it.
e.g. High voltage BPD, CVTs or Pot-coupler devices. (Bushing potential
devices, Capacitive voltage transformers, potential coupled devices). These
high voltage step down transformers rely on capacitive coupler to take a
"tickler" current off a high voltage line, typically in transformer bushings
as the lead passed through the long insulated tube inside a transformer
bushing. The resulting "
trickle" current is passed through a series of "tuned" circuits (RLC) to
produce a phase and ratio accurate reproduction of the high voltage to be
used in protection and/or metering circuits. These take high tech equipment
analysis to set them up using the resonant tuned circuits involved. Changing
the applies frequency would shift the phase of the protection circuits and
the line would get a trip command sent down the communication circuits to
open the transmitting ends.
The Eastern Seaboard Grid System has massive groups of Engineers working on
these grid synchro problems and the whole self-interest group concepts is a
waste of time and mostly nonsense. These circuits already have multiple
layers of massive, complex, protection schemes to protect against this kind
of thing and history has produced a need for constant improvement of the
technology and sophistication of these protection schemes. Contact a Senior
P&C Engineer at Hydro One or IESO and you can haggle this out with him until
after he retires, and then some, and still not come to a solid conclusion
for improvement.
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"Cross-Slide" wrote in message
Think about a 60 HZ standing wave....
HOW can that be applied to the grid? It cannot.
Say for example, you had a reference signal leaving Minneapolis, and
the peak of that wave will arrive in Chicago some time later. If there
is only One single line between these two centers, no problem...
Now add in the grid. The peak of that 60 HZ sine wave arrives at
Chicago, and the peak is also traveling from Minneapolis to Denver,
then on to Chicago.... The time is not the same for the two possible
paths.. There needs to be power moving back and forth...
With the wavelength of signal smaller than the possible distances in
the grid, you cannot have it all tied together without recirculating
power...
Even if a reference signal was assigned to one point in that example,
the reference cannot arrive at various points in the grid intact
because being a grid, there are multiple paths for it to follow.
Now add in multiple sources driving the grid, and you are left with
recirculating power... There is no way to have a "master" reference
for the grid...
The ONLY way that I can think of it working would be if all the
connecting points were assigned a time stamp reference from a MASTER
signal, and you would need tapped Delta transformers at each end of a
line.
Moving the delta taps could force power to flow in either
direction...
A tapped Delta transformer can change the phase angle, without
changing the voltage.
Can anyone illuminate this situation?
Anytime I have talked to electric power guys, they have never heard of
or thought about the fact that the grid cannot be in sync, without
having recirculating power..
They always refer to the grid has an infinite source and sink of
reactive power... it gobbles up the MVARS, or supplies them to keep
the generator perfectly in sync. You can open or close the wicket
gates to push more or less power to the grid. The voltage and
frequency are locked, but pushing harder against it will push more
amps... or pushing softer will push less amps...