From: Justin Richards <justin.richards@gmail.com>
To: Microcontroller discussion list - Public. <piclist@mit.edu>
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Date: Wed, 20 Oct 2021 18:02:52 -0700
Subject: [EE]: Calculating phase shift in high voltage A/C distribution cable
Thread-Topic: [EE]: Calculating phase shift in high voltage A/C distribution
 cable
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I think for RF there are coax cable constants for Vp or Vf which I am
guessing is Velocity of Propagation or Velocity Factor.

However, with High Voltage A/C @  50Hz does the question of phase shift
make sense.

And if so, what would be a typical value for Vp or Vf.

I ask as it appears that there was a situation where there were two ring
mains fed from each end with no "opens" and thus the way I see it is the
output of each HV step up transformer would be connected to each other via
a long length of cable.

Assuming two identical transformers (which will not be the case), I would
guess that if the outputs were directly connected at the transformers then
hypothetically no big deal.  No sparks, no increase in load etc. (again
assuming the connections were around the right way)

However, if the interconnecting cable was extended then I am guessing as
the length increased the phase shift would increase and the two
transformers would be fighting each other.

Does that sound reasonable.  And if so, how do I calculate phase shift over
the cable at 50Hz.  Can I assume a Vp of 1, or Velocity of propagation as
the speed of light.

So 33uS over 10kms ~
@50Hz, T is 20mS (360 degrees)
Phase shift =3D (33uS/20mS)*360
~ 0.6 deg phase over 10kms.

Am I way off.

Welcome any insights anyone may have.

Regards Justin
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