Inter Tripping Between Utility Breaker and Captive Power Plant Breaker

IF ONLY ONE LINE IS CONNECTED AT A TIME AND UTILITY SIDE BREAKER OPENS FIRST, WHY DO YOU NEED YOUR END BREAKER TO OPEN?

DURING NORMAL OPERATION WHETHER YOUR PLANT IS EXPORTING POWER OR IMPORTING POWER FROM UTILITY? IF SO WHAT IS THE PLANT LOAD AND IMPORT/EXPORT DETAILS?

We are importing aprrox 1 MW from the utility. Utility is our option for reliability in case GTG trips.

plant load is approx 25 MW and we have 5 GTGs of 7 MW each.

Furthur, we want intertripping because if there's no intertripping then there occurs a situation that when utility closes the breaker at their end, two different power sources (our GTG and grid) becomes synchronized at that particular breaker resulting in excessive current in the whole system.

You mean that they are going to synchronize assuming your plant is a dead load and not as a generator, without using any synchronization procedure.

You can have an instantaneous trip setting at your end to trip the same line on unacceptable current levels due to incorrect synchronization or you can have two lines in parallel, the other line will remain in service , when one line goes out. [The fault level will go up slightly in case of 2 lines are parallel, but this should be acceptable]. However, it is better to do synchronization at your end and I do not know how else tripping at your end can be done without using a signal from utility end.

You mean that they are going to synchronize assuming your plant is a dead load and not as a generator, without using any synchronization procedure.- yes, exactly. sir.
You can have an instantaneous trip setting at your end to trip the same line on unacceptable current levels due to incorrect synchronization or you can have two lines in parallel, the other line will remain in service , when one line goes out. [The fault level will go up slightly in case of 2 lines are parallel, but this should be acceptable]. However, it is better to do synchronization at your end and I do not know how else tripping at your end can be done without using a signal from utility end.
-we are synchronizing the grid at our end only.-we can only use one line at a timeas mentioned previously. The reason is anothor story whatsoever.-any guidance sir, on your behalf as to which type of protection is necessary for intertripping?

We are importing aprrox 1 MW from the utility. Utility is our option for reliability in case GTG trips.

plant load is approx 25 MW and we have 5 GTGs of 7 MW each.

Furthur, we want intertripping because if there's no intertripping then there occurs a situation that when utility closes the breaker at their end, two different power sources (our GTG and grid) becomes synchronized at that particular breaker resulting in excessive current in the whole system.

sir, can you provide me with some literature on dead line detection? Whether this technique can be applied in my case. I will contact you tomorrow. Yes, i am based in india.

power line Carrier inter trip,radio or pilot inter trip are the most dependable solutions invariably used with critical sets.

a plain uv element can not always detect remote open if generator is paralleled. UV protection will work if generator is not paralleled.

There are many other solutions - vector surge/ df/dt protections are frequently preferred. they can operate without remote communication.

You can avoid expenditure on inter tripping scheme by:

(a) Install a synchro check relay with lockout feature at the utility grid.

This relay will ensure the the breaker cannot be switched on when both end sources are not synchronized.

(b) Install a reverse active power relay, a reverse reactive power relay and an over votage relay on the incomer utility CB at your plant.

An unloaded line draws capacitive charging currents (reverse flow), voltage increases and power factor goes leading.