IN OLTC we observed "OUT OF STEP" Alarm, we have two different trans

IN OLTC we observed "OUT OF STEP" Alarm, we have two
different transformer, when both are in parallel this type
of alarm observed. what's the meaning of this alarm and why
it occurs???

Question Posted / sunil dave

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IN OLTC we observed "OUT OF STEP" Alarm, we have two different transformer, when both ar..

Answer / nasseem

Out of step means that the Two transformers at different tap.
i.e. TR-1 at tap n and TR-2 at tap n+1 or n-1.
And as you know the two transformers should have same tap
"if the two transformers have same tap size i.e 1.25% for
example" when it operated in parallel to prevent the
circulation current between the two transformers.

So it seems in your case if we assume TR-1 is master and
TR-2 is follower TR-1 change its tap position while TR-2
still at it is original tap.

Is This Answer Correct ?

13 Yes

0 No

IN OLTC we observed "OUT OF STEP" Alarm, we have two different transformer, when both ar..

Answer / karthik

For details of the parallel operation of transformer refer
the website:
http://nptel.iitm.ac.in/courses/IIT-MADRAS/Electrical_Machines_I/pdfs/1_14.pdf

According to the literature the cause for the out of step
operation maybe due to
1)Change in voltage ratio
2)Change of polarity

Is This Answer Correct ?

3 Yes

2 No

IN OLTC we observed "OUT OF STEP" Alarm, we have two different transformer, when both ar..

Answer / arun kumar

Out step alrm occurs when the tap changer goes to maximum /
minum tap position

Is This Answer Correct ?

3 Yes

9 No

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