7SR11 & 7SR12 Commissioning and Maintenance Guide
ยฉ2017 Siemens Protection Devices Limited Chapter 6 Page 4 of 72
2.17 Sensitive Power (32S) ........................................................................................................................... 56
2.18 Power Factor (55) .................................................................................................................................. 58
Section 3: Supervision Functions ........................................................................................................................... 60
3.1 CB Fail (50BF) ...................................................................................................................................... 60
3.1.1 Element Blocking ..................................................................................................................... 61
3.2 Voltage Transformer Supervision (60VTS) .......................................................................................... 62
3.2.1 1 or 2 Phase VT fail ................................................................................................................. 62
3.2.2 3 Phase VT fail ........................................................................................................................ 63
3.3 Current Transformer Supervision (60CTS) .......................................................................................... 64
3.3.1 7SR11...................................................................................................................................... 64
3.3.2 7SR12...................................................................................................................................... 65
3.4 Broken Conductor (46BC) ................................................................................................................... 66
3.5 Trip/Close Circuit Supervision (74T/CCS) ........................................................................................... 68
3.6 Magnetising Inrush Detector (81HBL).................................................................................................. 69
Section 4: Control & Logic Functions ...................................................................................................................... 70
4.1 Autoreclose (79) .................................................................................................................................... 70
4.2 Quick Logic ............................................................................................................................................ 70
Section 5: Testing and Maintenance ...................................................................................................................... 71
5.1 Periodic Tests ........................................................................................................................................ 71
5.2 Maintenance .......................................................................................................................................... 71
5.3 Troubleshooting ..................................................................................................................................... 72