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Has anyone got a circuit diagram (or copy) of the mains engineers friend, the Cossor Model 431M unit. Any help welcomed. Google drew a blank :-( Thanks fb599

Thanks for these. Exactly what I was looking for. Best Wishes, fb599!

I'm trying to establish the current carrying capacity of the following old UK imperial cable sizes laid in ground c. 1940/50: 0.0225" and 0.04" 11kV three core copper conductors (7strand/phase) paper insulated, lead covered and steel wire armoured. I have the values for steel belted but...

This is the first useful piece of information I've had on this, thanks! Any info on the F&P would be grateful indeed. If you can photocopy or scan the docs and send them to me, that would be great. Have a look what you have and drop me a note. Thanks Bob

I've been doing some work at an electricity utility in the UK that has some very old British Reyrolle TT12X2 switchgear and Ferguson & Pailin BV3 OCB Switchgear. If anyone can help with user manuals or operational manuals in .pdf that would be great. The Reyrolle kit has some small aluminium HV...

I have a 11/33kV 12/24MW CER Network transformer which I wish to set up back up over current protection. What I would like is the failure characteristics or maximum overload ratings for the transformer. Not just 1.2x FLC but I need to squeeze a couple of these in case one trips for about 10...

You could try core drilling an earth stake in and pouring bentonite in to make the connection with real earth. This is what we do at electrical substations that have bedrock underneath. Hope this helps. fb599

I have experienced two 33/11kV mal operations due to REF in the last two weeks due to external through faults. I'm checking the stability resistor settings and high impedance voltage settings. I saw a post for a spreadsheet that could make life easier, does anyone have a copy of this please ?

Does anyone have any experience of these please ? I operate version 2.0 and am being asked to upgrade due to memory buffer overload problems on this version. Has anyone had any serious issues with version 3.0 please. Thanks

Can anyone tell me how to format a number to have brackets automatically in an Excel spreadsheet when the numbers are negative values please. This is a financial application however ! Thanks

Does anyone know of any suitable software for calclating the earthing mat design of substations of 11-33 kV/415V design in a public power supply system ?

Thanks for the early reply. Yes, this REF 545 is providing back up protection to a circuit but it also controls the circuit breaker too. ie remote control and MMI local control.

Has anyone had a failure of this type of relay that could have possibly issued an "open" command to a circuit breaker without receiving such an instruction ? Any help welcomed.

Oh dear, 15 years ago I would have, and did agree with the management stance. "Let's move forward and invest in new technology" Now I would say why scrap a perfectly good backbone system. 70% of our network was re-populated with MIDOS relays. Now I am receiving obsolescent notices from...

I'm trying to establish a suitable workable database for all of our network and genetor protection equipment (including settings, ser. No's, type of relays etc) and am at a loss. Do I start designing a new Access db. or an SQL db. ? I do not want to re-invent the wheel. I have access to Amtech...

Can anyone direct me to a table of spacing distances for cleating of XLPE cables. I think I've looked everywhere ! Yes, I know what size cleats to use but I don't know what the typical cleat spacings should be for differing sizes and weights. Any URL's or guidance welcome. PS Enjoy the weekend...

Thanks for the replies. It is part of a bigger picture for a cable link compensation arrangement. Thanks all the same. I'll chime the PSSE up. fb599

I have a 185mm Al 11kV pair of cables rated at around 330A each. Both are feeding an area with max loading 140A. However, two 3.3MVA 11kV capacitors (175A each)have been added to this dist. area and are used from time to time. What will the cable max rating be if this new load is so capacitivly...

I'm not sure exactly what you're doing here but www.cyclosystems.com has a few circuits you may find useful and off the shelf equipment etc. They operate a zero crossing mains signalling system that we have been using here for 20 years.

Hi Tony McG We have a similar unit again one year old that has a 9.4 ppm reading. From what I've learnt in supporting literature below 10-15 is normal. These tests were carried out at the same lab and they are the first tests too for the unit. Loading has been cyclic and not always fully...