Breaker on 33kv Switch Gear Won't Close

or,is there more to this message been displayed on the screen of the switch gear

It really depends on the switchgear. Check the manual and supporting documentation carefully as it should be clearly explained.

Check the wiring to the pressure switch in case there is a break. Also check the pressure switch itself, if you are lucky it will be repairable or field-replaceable.

Please do not dissapoint him. We have lot of members who will search all details about his switchgear where it is, what the make, what is message,....and will reply .

Its a schneider electric 33KV switch gear and the transformer was also supplied by schneider electric.The message on the sreen on the swithch gear is"TR Gas".I think it means "transformer gas".This transformer powers the low voltage panel for the admin building and it gets its supply from the 33KV switch gear which in turn gets its own supply from gas turbine transformers.The transformer is a 33kv/415V transformer.Thank you sir

Have you called Schneider Electric?

A pressure/level switch contact blocking the circuit breaker and giving alarm is there for a reason. I would NOT start by assuming "the pressure switch is faulty" - that is a recipe for ending up with a large smoking hunk of steel and copper sitting in your substation. The reason for the blocking and alarm is to prevent someone from destroying your large-investment equipment while saying "The switch must be faulty. Let's just close the breaker anyway and see if it holds."

I'm making some assumptions on this transformer, since you haven't specified - is it a conservator type, with a separate cylindrical tank mounted up above the main tank? These often have a gas accumulation (Buchholz) relay that collects combustible gases that would be generated by problems in the transformer, and will trip and block for some level of accumulation. Combustible gases indicate any of a number of potential failures starting to develop in the transformer. In addition, the relay can serve as a low-low oil alarm, if for some reason there is oil loss to get the overall level down to the relay.

The oil level gauge up on the conservator tank probably also has contacts to indicate low oil level.

Whatever the case, I would recommend that you get someone qualified to investigate this and to do some diagnostics on the transformer to verify that it is okay. At a minimum, the oil should be sampled and analyzed for dissolved combustible gases. You also didn't say how long it has been de-energized - did it come out of service normally/manually, or did the breaker trip on some condition?

The transformer does not have a conservator tank; it just has fins on it and no fan attached to it for forced cooling.it's 3000KVA,33KV/415V transformer.The switch sits directly on top of the transformer by the side.I think the switch is for pressure and oil level in the transformer.I tried closing the breaker and it opened back immediately,so i was wondering if maybe i have to reset the switch the breaker will close,but the big question is how do i reset the switch if thats the solution? thanks for your support.

Most of the sensing devices on a transformer have alarm contacts that reset themselves. Oil level alarms are usually contacts actuated by the needle on an oil level gauge. On a sealed tank transformer like yours, this would usually be on the side, near the top. What you have on the top of the tank could be one of several things - a pressure relief device (shaped like a low cylinder like a classic landmine, about 30cm in diameter and 6-8cm high. It may have a little yellow semaphore to give visual indication) or a fault pressure or sudden pressure relay (SPR). The SPR senses a pulse of pressure change when an arc takes place within the transformer, and actuates a latching auxiliary relay. This latching relay then is supposed to trip and block closing of the breaker(s) feeding the transformer.

If you actually do have a SPR latched in, someone needs to investigate whether the transformer had a fault.

You still did not tell how the transformer was shut down originally. Was it removed from service by manually opening the breaker, or did the breaker trip automatically?

I still wouldn't recommend trying to bypass the blocking and closing the breaker, without verifying that there is not some problem with the transformer, the feeder cables, or the breaker itself (it's not uncommon for a breaker to have mechanical issues such as lack of proper maintenance and lubrication, causing it to trip free or fail to close).

Thank you very much Mr peter.This transformer in question has not been in use for say, 2 years before now.Recently i did some few checks and powered it on.During operation recently the transformer just tripped and refused to close.I have tried closing the breaker and the breaker has refused to close.Are they any precise test you'll want me to carry out on the transformer?The description you gave about the SRV fits the device on my transformer.