Legacy 11kV switchgear GEC type BVRP17

[ScottyUK]

Question for those with experience of old British-manufactured oil-filled switchgear:

GEC supplied their BVRP17 series of oil circuit breakers in a number of guises. The two basic designs are a 400A / 800A type, and a 1200A type. Each of the two types has a number of variants with differences in the design of the fixed contact cluster. The key difference is that some have five 'petals' (sprung contacts) and some have six. A third design exists from the same era which has four petals, although we don't have any of that type among our population. The thermal ratings and breaking capacity of our breakers are equal regardless of the cluster design, but there is clearly some reason for there being several variants - I just can't find it recorded anywhere.

All our breakers were supplied as part of the same contract and are of sequential serial numbers. The manufacturer's manual shows all three cluster designs alongside each other so it isn't a design change over time. We have a handful of breakers on motor starting duty, and the remainder serve distribution transformers: so far this is one of the few plausible engineering reasons we can put forward why there are differences in our breakers, although over the passage of time we now have both 5-petal and 6-petal types in motor service and in transformer service. The other possibility is that there is no significant performance difference, and that some 5-petal types have simply been supplied as replacements for original 6-petal types as parts have been replaced over the past 40 years.

Any assistance appreciated.

 

[Hoxton]

There is a market for refurbished switchgear, it seems that a lot of suppliers offer vacuum breakers in replacement trucks.

In any case they may have knowledge of the build of the original breakers. Suggest you try asking them. Try Slater Electrical in Newcastle, for example.

Ferguson, Palin became AEI Switchgear, became GEC Switchgear, Became Alsthom, became Alstom, became..... have you thought of asking Schneider?

These old UK factories often span off a service company when they closed, and abandoned all those old fogeys. I could not find one in Manchester, but there may be one lurking there

 

[ScottyUK]

Hello Hoxton,

Yes, Slater are an option for salvaged and overhauled breakers. Alcomet manufacture spare contacts to the original designs and offer a decent service at a not-too-outrageous price. Neither seem to know why there are three variants of the same contact with equal thermal rating. Lots of speculation!

Schneider seem more keen on selling the VMX than supporting the old oil types: "You want a what...?" was the response to our enquiry about spare turbulators. The VMX certainly has benefits and would have a lot more if they could get PD properly under control and make the whole thing a little more robust. We have a contact in what was Areva's service group who knows a lot about these older products and if I get a definite answer I'll post it here.

 

[ScottyUK]

Attached a couple of pages from the OEM's manual showing the different designs I'm trying to find out about.

 

[ppedUK]

Looks like it depends on which form of breaker you have (A/B/C or A2/B2/C2). The manual describes flat bottom and rounded bottom tanks relating to the form of breaker and my guess is that you have the rounded bottom tanks? If that is correct, then it seems that you can have five or six petals on the cluster for 400/800A, but you can only use the 6 petal type on the 1200A, which would make sense as you would expect the current carrying capacity of 6 petals to be greater than 4 or 5. Having said that, over the years you might have a mix of both if the wrong ones have been fitted during overhaul.

There is also mention (first para on page 2) of the different types of contact depending also on fault rating, so again you would maybe expect the highest number of petals on the breakers which have the higher fault withstand. I seem to remember that you had an unusually high fault rating (26.2kA??) for the BVPR17 gear on your plant, or was that another place?

 

[ScottyUK]

Hi ppedUK,

Yes, we have a 400A Form B2 design. I've received some information from Schneider which I'll include here once I fully clarify a query. In essence the 4-petal design has a 20kA breaking capacity, where the 5-petal and 6-petal designs both have 26.3kA (500MVA @ 11kV) breaking capacity.

We still have uncertainty whether the 1200A 6-petal contact is exactly the same as the 400A/800A 6-petal contact or whether it is designed to accommodate a slightly larger diameter moving contact. This question has arisen because the earlier Form B and Form C designs reportedly have a larger diameter (1" compared with 7/8") moving contact and a completely different fixed contact, but we don't know whether the larger moving contact was carried over onto the 1200A Form B2 and Form C2 designs. Now that someone has asked the question the seed of doubt has been sown!

You have a good memory. We have a fairly high fault level at our site, and as a result of network reinforcement plus the addition of a fair amount of local embedded generation we now have to keep one of our intake transformers off the bars to keep the fault level within the capability of the 11kV gear.

 

[ScottyUK]

OK, further confirmation from Schneider came through this morning (thanks to Tom Lavin answering his emails early on a Saturday morning):

4-petal contact:

OCB type & rating: Form B2 400A / 800A​

OCB Breaking capacity: 20kA​

Male contact diameter: 7/8"​

5-petal contact:

OCB type & rating: Form B2 400A / 800A​

OCB Breaking capacity: 26.3kA​

Male contact diameter: 7/8"​

6-petal contact

OCB type & rating: Form B2 400A / 800A and Form B2 1200A​

OCB Breaking capacity: 26.3kA​

Male contact diameter: 7/8" for 400A/800A or 1" for 1200A​

The 400A/800A male contact is 7/8" diameter, and the 1200A male contact is 1" diameter. Both diameters are compatible with the 6-petal female contact. Only one 6-petal female contact design exists for the BVRP17 breaker series.

Hopefully this ends the confusion for us, and will be useful information for anyone looking in future.

 

[ppedUK]

Thanks for posting the info Scotty. Hopefully I'll never need it, but you never know it may come in useful one day!

I remembered the "unusual" fault rating of your gear because I and someone else commented in one of your posts a few years back, that we had never come across a BVRP17 with a 500MVA fault rating, and I still haven't seen one to this day. I can live with that though.

 

[ScottyUK]

Well we can put that shortfall to rights!

Doesn't look much (any?) different to the 250MVA breaker, at least not externally.

 

[ppedUK]

Thanks for the photos Scotty, my life is now complete .

As you say, looks exactly like the 250MVA gear.

P.S. I wasn't doubting you, just never seen such a beast in the wild!

 

[GroovyGuy]

Hi Scotty,
Are these the same CBs as sold under the name "Brush"? I have seen "Brush" CBs at many old facilities here in Canada, eh.
GG

"I have not failed. I've just found 10,000 ways that won't work." Thomas Alva Edison (1847-1931)

 

[ScottyUK]

Hi GG,

Brush Switchgear were one of many companies competing in the British switchgear industry at that time and a direct competitor to GEC Switchgear. The Brush switchgear business merged with South Wales Switchgear to form Hawker-Siddeley Switchgear, with a further merger with Whipp & Bourne occuring during the period under FKI ownership.

The BVRP and VSI are both 11kV bulk oil designs intended for the UK market during a period of huge investment in the distribution utilities and heavy industry. The Brush VSI was a popular breaker and there are still a lot of them out there. Here's a photo of the VSI for comparison - took a bit of finding, Google images is full of VCB retrofits for the VSI!