ATS for the MV and LV 1

[slavag]

Dear All.
I have today a hot discaussion with designer and end-user.
We have programmed and commissionied some ATS ( two infeedes and coupler) for the 6.6kV.
Load is lot of async. motors. Designer didn't include in the system deadbus check. I request it, end-user was against
deadbus check too. OK, I will provide what them want, but from my point of view isn't right and always we do in our systems: double criterions, infeed open and deadbus check.
What is your opinion?
Thanks in advance
Regards.
Slava

 

[rbulsara]

slava:

If you are taking abut main-tie-main breaker scheme, I think it is a must.

What is your role? It you are supplier of the equipment, I would include it whether or ot someone specified it.

In the end, you need to put your concerns and recommendations in writing and let owner make the decision.

Just be careful when you say an ATS, in the USA it normally taken as double-throw switching arragement a lot different animal than a breaker scheme.

 

[slavag]

Hi Rafiq.
Thanks for your reply.
Yes it's main-tie-main.
"Simple" system, no voltage on main, second main and tie are OK, undervoltage trip and after some small time close command to tie.
I wrote all before few days and today we discaussed about it with designer and end-user, nothing help, I used all arguments.
My role, we supply relay, programming and commissioning.
Swg supplyed by others, design by others.
Best Regards.
Slava

 

[rbulsara]

slava:

I can undestand your tough position. I have been there a few times and it is very furstrating. Somehow do not make it an argument but layout your concerns and what can go wrong if these safe gurads are not in place. Possibly involve others, like the switchgear mfr or some other experienced engineer/VP in your firm, who can persuade the owner.

Based on what you said, are you fitting up a switchgear with controls? If so, I would just built it in as long as the costs are covered and not make an issue as there is a lot of liability at stake as a provider.

I am sure you looked at other safety interlock requirements beside the dead bus check.

 

[slavag]

Hi Rafiq.
Thanks a lot again.
I'm a exp. eng in our firm .
I've had now phone conversion with end-user and close this issue. Swg mnf. provide this swg as designed and on the site, we will add dead bus check function w/o any additional price ( it's really small changes in the soft and wiring).
BTW, designer agree add some simple NV relays, but it also not so sutible ( operating range 0.7Unom).
Best Regards.
Slava

 

[rbulsara]

slava:

Good. I figured that much that you are the man! I can tell from your contributions here on this site. I meant for political/PR reason it helps to have someone else involved to diffuse some tense situations.

I myself have often been culprit of being too forceful on technical issues, but now I am learing to be more tactful.

 

[slavag]

Dear Rafiq.
Many thanks for your words.
I'm learn to be more tactful too, but from time to time it is very dificult.
Best Regards.
Good Luck
Slava