Siemens 7SR21 Manual page 3

2.12 Thermal Overload (49)............................................................................................................44
2.13 Over/Under Voltage ................................................................................................................46
2.13.1 Phase Under/Over Voltage (27/59)...........................................................................46
2.13.2 Undervoltage Guard (27/59UVG) ..............................................................................48
2.13.3 Vx Under/Over Voltage (Vx 27/59) ..........................................................................49
2.13.4 NPS Overvoltage (47) ................................................................................................51
2.13.5 Neutral Overvoltage (59N) .........................................................................................53
2.13.6 Definite Time (59NDT) ...............................................................................................53
2.13.7 Inverse Time (59NIT) .................................................................................................54
2.13.8 Under/Over Frequency (81) .......................................................................................55
Section 3: Supervision Functions ......................................................................................................57
3.1 CB Fail (50BF) .......................................................................................................................57
3.2 Voltage Transformer Supervision (60VTS)...........................................................................59
3.2.1 1 or 2 Phase VT fail....................................................................................................60
3.2.2 3 Phase VT fail ...........................................................................................................60
3.3 Current Transformer Supervision (60CTS)...........................................................................61
3.4 Broken Conductor (46BC).....................................................................................................63
3.5 Trip Circuit Supervision (74TCS) ..........................................................................................65
3.6 Magnetising Inrush Detector (81HBL) ..................................................................................66
Section 4: Control & Logic Functions ................................................................................................67
4.1 Autoreclose (79)......................................................................................................................67
4.2 Quick Logic .............................................................................................................................67
Section 5: Testing and Maintenance ..................................................................................................68
5.1 Periodic Tests .........................................................................................................................68
5.2 Maintenance............................................................................................................................68
5.3 Troubleshooting ......................................................................................................................68
©2010 Siemens Protection Devices Limited
7SR21 & 7SR22 Argus Commissioning and Maintenance
Chapter 6 Page 3 of 69