Areva MiCom P120, Technical Manual

Page: 244 / 668

P12x/EN AP/A96 Application Guide
Page 22/80
MiCOM P120/P121/P122/P123
6.4.1 Metrosil units for relays with 1A CT
The Metrosil units with 1A CTs have been designed to comply with the following restrictions:
−
At the relay voltage setting, the Metrosil current should be less than 30mA rms.
−
At the maximum secondary internal fault current, the Metrosil unit should limit the
voltage to 1500V rms if possible.
The Metrosil units normally recommended to be used with 1Amp CTs are shown in the
following table:
Nominal Characteristics Recommended Metrosil Type
Relay Voltage
setting
C
β
Single pole Relay Triple pole relay
Up to 125V rms
125 to 300V rms
450
900
0.25
0.25
600A/S1/S256
600A/S1/S1088
600A/S3/1/S802
600A/S3/1/S1195
NOTE: Single pole Relay Metrosil Units are normally supplied without
mounting brackets unless otherwise specified by the customer.
6.4.2 Metrosil units for relays with 5A CT
These Metrosil units have been designed to comply with the following requirements:
−
At the relay voltage setting, the Metrosil current should be less than 100mA rms (the
actual maximum currents passed by the units shown below their type description)
−
At the maximum secondary internal fault current the Metrosil unit should limit the
voltage to 1500V rms for 0.25 second. At the higher relay settings, it is not possible to
limit the fault voltage to 1500V rms, hence higher voltage have to be tolerated
( indicated by * ,** , *** ).
The Metrosil units normally recommended for the used with 5 Amps CTs and single pole
relays are shown in the following table:
Recommended Metrosil Type Secondary
Internal fault
current
Relay Voltage Setting
Amps rms
50A
Up to 200V rms
600A/S1/S1213
C= 540/640
35mA rms
250V rms
600A/S1/S1214
C= 670/800
40mA rms
275V rms
600A/S1/S1214
C= 670/800
50mA rms
300V rms
600A/S1/S1223
C= 740/870*
50mA rms
100A
600A/S2/P/S1217
C= 470/540
35mA rms
600A/S2/P/S1215
C= 570/670
75mA rms
600A/S2/P/S1215
C= 570/670
100mA rms
600A/S2/P/S1196
C= 620/740*
100mA rms
150A
600A/S3/P/S1219
C= 430/500
100mA rms
600A/S3/P/S1220
C= 520/620
100mA rms
600A/S3/P/S1221
C= 570/670**
100mA rms
600A/S3/P/S1222
C= 620/740***
100mA rms
NOTE: * 2400V peak
** 2200V peak
*** 2600V peak
In some cases, single disc assemblies may be acceptable, contact
AREVA T&D for detailed information.
The Metrosil units used with 5 Amps CTs can also be used with triple
pole relays and consist of three single pole units mounted on the
same central stud but electrically insulated from each other. To order
these units please specify “Triple pole Metrosil type”, followed by the
single pole type reference.