what is the purpose of earthing leakage relay(ELR) ?
>How to fix the ELR in 125 KVA (i.e connections)
Dear Nagaraju ;
We use ” ELR – Earthing Leakage Relay ” to realize the ” Earth Fault Protection ” for an electric notworks, where in the most of case all protection were been installed before without this kind of protection and we want to add it, so, instead to change the circuit brekaer to have a new one built-in with this protection, we can add ” ELR ” where the output order of the ELR should be connected to a ” Shunt Trip ” installed in the circuit breaker.
For exp, if you want add an ” ELR ” to the main protection of your installation, that means to the main circuit breaker, you should add to the circuit breaker a ” Shunt Trip “, and install the ” Torroide ( special current transformer delivered with the ELR ) ” around the main cable ” 3 phases + Neutral ” but without the PE cable , connect by a special wire between the Torroide and the input of ELR, supply the ELR by the necessary voltage, then connect the output of ELR to the Shunt Trip. Nothing that there's many kind of ELR that are : Fixe, adjutable with or without a timming delay, and many Diameters of trhe Torroide ( depending the cables ).
Once there's a earth leakage current above the adjustment one in te ELR, a trip order to the shunt trip will be delivered and the circuit brekaer will trip.