Siemens 7SR10 Argus Series Manual page 246

Contents
Section 1: Common Functions ............................................................................................................................ 4
1.1 Multiple Settings Groups .................................................................................................................... 4
1.2 Binary Inputs ..................................................................................................................................... 5
1.2.1 Alarm and Tripping Inputs ..................................................................................................... 5
1.2.2 The Effects of Capacitance Current ...................................................................................... 6
1.3 Binary Outputs ................................................................................................................................... 7
1.4 LEDs ................................................................................................................................................. 7
Section 2: Protection Functions .......................................................................................................................... 8
2.1 Time delayed overcurrent (51/51G/51N) ............................................................................................. 8
2.1.1 Selection of Overcurrent Characteristics ............................................................................... 9
2.1.2 Reset Delay ....................................................................................................................... 10
2.2 Voltage dependent overcurrent (51V) ............................................................................................... 11
2.3 Cold Load Settings (51c) .................................................................................................................. 11
2.4 Arc Flash Detection (50AFD) ............................................................................................................ 11
2.5 Instantaneous Overcurrent (50/50G/50N) ......................................................................................... 12
2.5.1 Blocked Overcurrent Protection Schemes ........................................................................... 13
2.6 Sensitive Earth-fault Protection (50SEF) ........................................................................................... 14
2.7 Directional Protection (67) ................................................................................................................ 15
2.7.1 2 Out of 3 Logic .................................................................................................................. 17
2.8 Directional Earth-Fault (50/51G, 50/51N, 50/51SEF) ......................................................................... 18
2.8.1 Compensated Coil Earthing Networks ................................................................................. 18
2.8.2 Isolated Networks ............................................................................................................... 20
2.8.3 Minimum Polarising Voltage ............................................................................................... 20
2.9 High Impedance Restricted Earth Fault Protection (64H) ................................................................... 21
2.10 Negative Phase Sequence Overcurrent (46NPS) .............................................................................. 22
2.11 Undercurrent (37) ............................................................................................................................ 23
2.12 Thermal Overload (49) ..................................................................................................................... 23
2.13 Under/Over Voltage Protection (27/59) ............................................................................................. 24
2.14 Neutral Overvoltage (59N) ............................................................................................................... 25
2.14.1 Application with Capacitor Cone Units ................................................................................. 26
2.14.2 Derived NVD Voltage ......................................................................................................... 26
2.15 Negative Phase Sequence Overvoltage (47) .................................................................................... 26
2.16 Under/Over Frequency (81).............................................................................................................. 26
2.17 Power (32)....................................................................................................................................... 27
2.18 Sensitive Power (32S) ..................................................................................................................... 27
2.19 Power Factor (55) ............................................................................................................................ 27
Section 3: CT Requirements ............................................................................................................................ 28
3.1 CT Requirements for Overcurrent and Earth Fault Protection ............................................................ 28
3.1.1 Overcurrent Protection CTs ................................................................................................ 28
3.1.2 Earth Fault Protection CTs.................................................................................................. 28
3.2 CT Requirements for High Impedance Restricted Earth Fault Protection............................................ 28
Section 4: Control Functions ............................................................................................................................ 29
4.1 Auto-reclose Applications ................................................................................................................. 29
4.1.1 Auto-Reclose Example 1 .................................................................................................... 30
4.1.2 Auto-Reclose Example 2 (Use of Quicklogic with AR) .......................................................... 31
4.2 Quick Logic Applications .................................................................................................................. 32
4.2.1 Auto-Changeover Scheme Example ................................................................................... 32
Section 5: Supervision Functions ...................................................................................................................... 33
5.1 Circuit-Breaker Fail (50BF) ............................................................................................................... 33
5.1.1 Settings Guidelines ............................................................................................................ 33
5.2 Current Transformer Supervision...................................................................................................... 35
5.3 Voltage Transformer Supervision (60VTS) ........................................................................................ 36
5.4 Trip/Close Circuit Supervision (74T/CCS) ......................................................................................... 37
5.4.1 Trip Circuit Supervision Connections ................................................................................... 37
5.4.2 Close Circuit Supervision Connections ................................................................................ 39
5.5 Inrush Detector (81HBL2) ................................................................................................................ 40
5.6 Broken Conductor / Load Imbalance (46BC) ..................................................................................... 40
5.6.1 Broken Conductor example ................................................................................................ 41
5.7 Circuit-Breaker Maintenance ............................................................................................................ 41
© 2018 Siemens Protection Devices Limited
7SR10, 7SR11, 7SR12 Applications Guide
Chapter 7 Page 2 of 41