CEE Relays Ltd.

87C Whitby Road, Slough, SL1 3DR

Telephone: (01753) 576477        Fax: (01753) 825661

Website: www.ceerelays.co.uk

How do I set the RMS7000 and RMS700 relays?

Setting the RMS7992 and RMST7992 relays
This is explained in the commissioning instructions, with the different settings summarised on page 21.

Setting the RMS700 and TMS700 series relays?
This is explained in the commissioning instructions, but a simple summary of how to do this can be downloaded by clicking here.

Setting the ITG series relays
This is explained in the commissioning instructions in full. Both the time and current settings are set using the DIL switches on the faceplate of the relay using the formulae quoted on the faceplate.

The formulae for the overcurrent pick-ups include a value "IA", which is quoted on the relay's label. For example, a 5A relay with a (0.25-2)In low-set overcurrent pick-up would have IA=2.5A or IA=0.5In written on the relay's label. A 1A relay with the same setting range would have IA=0.5A, or IA=0.5In written on the label.

The formulae for the earth-fault pick-ups do not include IA. One of two formulae is quoted on the faceplate, depending on whether the relay is to be residually connected, or connected to a core-balanced CT. These formulae include K0, which can be set to one of two values during commissioning. For the lower residually connected setting range or core-balanced CT connection, K0 can be set to 0.1 or 0.2. For the higher residually connected setting range, K0 can be set to 0.2 or 0.4.

As with the RMS7000 and RMS700 series, the IDMT time setting is the time that the relay will operate in when the current is 10 times the IDMT pick-up. For example, if I> is set to 0.8, and the CT ratio is 150/1, then t(I>) is the time that the IDMT curve will operate in if 1,200A is flowing through the cable.