Electrical Engineering - power factor transformer difference

Author

power factor transformer difference

newsey

2007-06-25, 9:25 am

Can power factor be different in each side of a generator transformer that's
connected to an infinite bus (grid)?

Example...

Generator at LV connected to a HV public utility grid via a step-up
transformer.
The generator is running in 'power factor' control mode.
This means that the alternator will always run at the desired power factor,
in this case it's unity.
There's more than enough reactive power being generated elsewhere on the
grid for load that requires it.

Newsey

Fred Lotte

2007-06-25, 5:25 pm

In article <n_Lfi.28237$aS5.19203@fe1.news.blueyonder.co.uk>,
"newsey" <disposable1@blueyonder.co.uk> wrote:

> Can power factor be different in each side of a generator transformer that's
> connected to an infinite bus (grid)?

In a word, yes.

The transformer is a load on the generator/system. One of them
(or both) have to supply the reactive requirements which will be
reflected in the power factor.

All that being 'infinite' confers to a bus is constant voltage
for 'any' load. It says nothing about the power factor of the
load.

--
Fred Lotte
flotte@nospam.stratos.net

Govind

2007-06-26, 1:25 pm

On Jun 25, 2:34 pm, "newsey" <disposab...@blueyonder.co.uk> wrote:
> Can power factor be different in each side of a generator transformer that's
> connected to an infinite bus (grid)?
>
> Example...
>
> Generator at LV connected to a HV public utility grid via a step-up
> transformer.
> The generator is running in 'power factor' control mode.
> This means that the alternator will always run at the desired power factor,
> in this case it's unity.
> There's more than enough reactive power being generated elsewhere on the
> grid for load that requires it.
>
> Newsey

Hi

Generator is running in constant power factor mode so all generator
that are connected to same grid through the unit transformer shall see
the same power factor anywhere in the grid connected system

Govind

vijayeee82@gmail.com

2007-06-27, 1:25 pm

On Jun 25, 2:34 pm, "newsey" <disposab...@blueyonder.co.uk> wrote:
> Can power factor be different in each side of a generator transformer that's
> connected to an infinite bus (grid)?
>
> Example...
>
> Generator at LV connected to a HV public utility grid via a step-up
> transformer.
> The generator is running in 'power factor' control mode.
> This means that the alternator will always run at the desired power factor,
> in this case it's unity.
> There's more than enough reactive power being generated elsewhere on the
> grid for load that requires it.
>

hii arul

see strictly speaking there will a very negligile difference in
power factor betwwen LV AND HV sides of transformer. it is because a
transformer draws a negligible magnetsing current ( reactive power) to
maintain the varying flux and a very little real power due to the
loses in it. so if u ask me i will just say NO. because what that a
transformer draws a just a trivial thing right. bye

daestrom

2007-06-29, 5:25 pm

"newsey" <disposable1@blueyonder.co.uk> wrote in message
news:n_Lfi.28237$aS5.19203@fe1.news.blueyonder.co.uk...
> Can power factor be different in each side of a generator transformer
> that's connected to an infinite bus (grid)?
>
> Example...
>
> Generator at LV connected to a HV public utility grid via a step-up
> transformer.
> The generator is running in 'power factor' control mode.
> This means that the alternator will always run at the desired power
> factor, in this case it's unity.
> There's more than enough reactive power being generated elsewhere on the
> grid for load that requires it.
>

Under any significant load, the pf on both sides is, for all intents and
purposes, the same. Under very light load, the small magnitizing current
within the transformer will make the supplying side have a different pf then
the load side.

daestrom

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