Line PT phase

[Sn00ze]

Due to breaker physical dimensions it seems the line PT (phase B - middle) is restricting constructability.

Is there any issues with moving the Line PT to the other phase? say A as far as protections, etc goes?

 

[jghrist]

It depends on what you are using the voltage for.

 

[Sn00ze]

Hi jghrist,

thanks for your reply. Would you mind expanding on that? Which functions/protections would be the ones to look for?

 

[bacon4life]

If it is used for synchronizing or aurora protection, it will be critical to coordinate the phase change with the relaying folks.

In my region, the B phase transmission voltage is about 1% higher than A and C phases, so switching phases with the PT may have a slight impact on voltage control and on state estimator solutions.

 

[marks1080]

In general, no there won't be an issue. Make sure the protection folks know you made the change!

SCADA folks may need to tweak something as well. Best to give everyone a heads up, but all original functionality should still be achievable.

 

[cranky108]

We use B phase because that was the phase we had line carrier on, so there was a PT stand their.

But it seems more natural to be on A phase because many relays assume A phase for the 25 functions.

 

[jghrist]

Synchronizing in particular would generally prohibit changing phase unless the synchronizing equipment can adjust for phase angle.

 

[Sn00ze]

Thank you very much for your insight guys! I really appreciate it.

I will take these into consideration.

 

[marks1080]

changing phases will mean other work needs to be done, but don't let anyone tell you it can't be done.

Of course if you change phases and the signal is being used for synchronizing than you'll need to make adjustments elsewhere. But all of that can easily be done by a qualified P&C engineer.