We have 20 MW turbo alternator, its generated frequency is 50 HZ, & Alternator RPM is 1500.

The commissioning team configured the frequency in 0 to 100 % in the DCS, where as actual frequency output from the transducer was 45 to 55 HZ.

The commissioning team configured the alternator RPM to 60, while the actual alternator running at 1500 RPM.

Could you please advise what would be the reasons.

 

Congratulations on your 50 Hz, four-pole, 20 MW turbo-alternator.

Have you asked this question of the commissioning team?

Have you looked at the code running in the DCS to see how the scaling which was chosen by the commissioning team affects other functions, if at all? It may be that it was thought to be easier to change this configuration to make something else work than to change the other code.

Most of the commissioning activities I have been party to have usually been severely limited by schedule over-runs by the mechanical erection and assembly team and a failure on the part of the project supervision team to extend the project end-date to allow the commissioning team time to properly complete their activities. Many times the commissioning team is working around the activities of the mechanical erection and assembly team because the mechanical portion of the installation was not managed properly and therefore an orderly progression of commissioning activities isn't possible.

Lastly, contrary to what one would think about installing multi-million dollar equipment, usually some very junior and inexperienced people are sent to site to do the work. Why? Because the senior people don't want to travel to sites, and send the younger people, as likely happened to them when they started their careers.

The more I work in this field the more it just seems bass-ackwards. Or am I the only one who feels this way? I just don't see how corporations can afford to send junior, inexperienced people to sites to install costly and complicated pieces of equipment. It just boggles the mind. Not that there aren't some very talented and intelligent junior people recruited for these types of jobs. It's just not fair to them or to the Customers who purchased this equipment to send people who, given a reasonable time to complete their activities could do a fantastic job usually end up forced to work extremely long hours under lots of pressure to complete work which can't progress in a logical fashion and so ends up being not properly commissioned.

This isn't always the case, but it seems to more the rule than the exception. So, have some empathy for the commissioning crew. Try to understand what they might have been subjected to, especially if you were present during the commissioning and can recall what was happening at the time.

And look at the code in the DCS and see if it's just a simple I/O configuration change, or if other changes may be necessary. If it's a new plant, you should have some warranty on the equipment which should allow you to be able to get someone to site to assist with correcting what appears (from your description) to be incorrect.

And let us know what happens.

 

Thanks for your information.

I can change easily to arrive the correct engineering unit. I am interested to know the nomeclature of the power sector frequeny / rpm

regards'
ravi

 

Are you asking for the typical engineering units used for frequency and RPM?

Frequency is usually expressed in Hz. And RPM is an engineering unit expression for speed.

You could scale your frequency input from that transducer, if the DCS wants it in percent, as 90% - 110% (45 Hz to 55 Hz).

But, I'm not clear about the RPM question.