Earth Fault Protection relays

[GAZ4333]

Would someone please be able to explain to me how Earth Fault protection relays work for electrical industry on LV Switchboards.

Regards

GAZ

 

[JohnnyHS]

http://blog.sparksdirect.co.uk/rcd-...rinciple-of-operation-rcd-rccb-rcbo-cbr-srcd/

rather than type out this is what i have found useful. i believe it is rarer to find just a Earth Fault protection relay more likely to have it included in a Residual Current Operated Circuit Breaker With Integral Overcurrent Protection. (RCBO) That way you get earth fault currents, overloads and short-circuits protection.

Hope that helps.

Johnny H-S BSc(Hons) MInstMC

Engineers like to solve problems. If there are no problems handily available, they will create their own problems.

 

[ScottyUK]

From the world of instruments that might be case, but dedicated earth fault relays are pretty common in the electrical world.

Most E/F relays are a sub-set of overcurrent relays, and are basically a standard overcurrent relay connected to either a CT in the neutral earthing connection or in the residual of a three-phase CT group. Earth fault relays may be instantaneous, definite minimum time, or inverse-time. Inverse-time relays often have a high-set value above which an instantaneous trip occurs.

One of the better known types is the GEC Relays MCGG, now marketed by Areva

http://www.areva-td.com/solutions/liblocal/docs/LegacyProducts/mcggsalesen.pdf

You could do worse than register and download the Network Protection & Automation Guide from Areva's website, or trawl the net for the Art & Science of Protective Relaying. I have to admire the logic by which Areva decided to stop publishing the NPAG: "It's proving very popular, therefore we'll discontinue publication".


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If we learn from our mistakes I'm getting a great education!

 

[slavag]

Hi.
In additional to Scotty's recommendation...also with registration..., a very good documents on the site:

http://www.i-gard.com/

exactly what you need, ground/earth fault on LV SWB.

Good Luck.
Slava

 

[GAZ4333]

Many thanks guys if you can think of any more information, i know it will all help.

Regards

Gaz