Gas turbine mark 5 And frame 6. Gt/3 black start test carried out in gas.

> 33kv breaker open.
> 380v standby supply MCC supply off.
> Gt/3 fsnl reached.
> Gt/3 11kv breaker closed on dead bus selection but breaker tripped with reverse power.

here is notable question.
reverse power mean when your gas turbine one unit connected with another gas turbine unit, and here this 33kv breaker was open, and 11kv breaker tripped. why its so strange and we did't succeeded in black start test still now? plz some body shade to his lights.

 

We'll try to shade his light for you.

Does the turbine have a diesel starter?

If not, does the plant have an emergency diesel used to supply power to the starting means?

Was the reverse power trip initiated from sequencing in the Mark V or by an external reverse power relay?

What happened to the frequency when the generator breaker closed? Did it increase or did it decrease? Or did it remain the same?

What were all the alarms generated between the time the generator breaker closed and the time the generator breaker opened?

 

ratchet

It appears from the post that GT3 started, achieved full speed no load and closed the generator breaker.

And then opened the generator breaker. Trip is a bad word.

During black start testing, I have found that if one does not set the spinning reserve setting to zero the generator will attempt to load on a "dead bus".

Since the load does not exist, well you think about it.

Hope this helps!!!

CTTech

 

CCTech... I disagree with your premise that it wasn't a breaker "Trip!"

Any opening of the breaker, other than manual action, must result from the "Protection" System, hence a "Trip!"

I will concede, however, to any argument that "Trip" action(s) can be prioritized/categorized as to severity!

Regards, Phil Corso

 

Phil,

I agree in your observation to a certain degree. The post does not describe a turbine trip. That led me to believe the control system merely opened the breaker.

I try to keep the word "trip" to trip from load due to abnormal conditions. ie protective devices.

For instance, during turbine loading an abnormal condition is detected. The control system then unloads the generator, opens the breaker, and begins "controlled" turbine shutdown or just remains a full speed no load.

Although a abnormal condition was detected, I would not consider the above description a trip. GE does not either.

However, we probably need more information to really determine the severity of the situation. My bad.

Any and all feedback is welcome. Thanks Phil

CTTech

 

Phil,

Just more food for thought. In some of the Mark V turbine controllers I have been exposed to, the Mark V command to open breaker operates a separate trip coil than the digital protection relay.

If the DGP opens the breaker opens the breaker then the turbine trips, if the Mark V opens the breaker a "non trip" situation exist with a controlled turbine shutdown.

Thanks
CTTech

 

yes Mr CSA .. answer for your question is follows.

1.. the reverse power trip initiated from the external reverse power relay.

2.. we did,t watch to frequency during tripping.

3.. there were 2 alarm appeared between the generator breaker closed and opened. ie generator breaker trip droop no 197.
2nd one Reverse power fault droop no 416.

4.. yes we have a diesel starter.

 

1.. For some reason the external reverse power relay sensed current flowing in the reverse direction. Perhaps there is a wiring problem, or some breaker was not in the indicated position.

2.. It is suggested that when performing tests like this (operations not typically performed) that you set up some data-gathering using the VIEW tools in advance to monitor important parameters so that if there is a problem you have some data to analyze. Did anyone look at the Trip History (or better, print the Trip History) to see if there was any information which might be helpful in understanding what happened? Such as, did FSR suddenly change when the breaker closed, or did turbine speed change suddenly when the breaker closed?

3.. No surprise here.

4.. Congratulations.

 

> Gas turbine mark 5 And frame 6. Gt/3 black start test carried out in gas.

> 33kv breaker open.
> 380v standby supply MCC supply off.
> Gt/3 fsnl reached.
> Gt/3 11kv breaker closed on dead bus
>selection but breaker tripped with reverse power.

> here is notable question.
> reverse power mean when your gas turbine one unit connected with another
> gas turbine unit, and here this 33kv breaker was open, and 11kv breaker
> tripped. why its so strange and we did't succeeded in black start test still now?
> plz some body shade to his lights.

Can you answer at least one of these questions please?

1. Does your emergency diesel is connected to the same bus with your GT? Or they somehow can be assumed to share the same bus?

2. Reverse power was the actual scenario that you could confirm, i.e. not due to some relays malfunction?