Siemens 7SR105 Rho - Introduction

7SR105 Rho Description Of Operation
©2018 Siemens Protection Devices Chapter 1 Page 2 of 57
Contents
Section 1: Introduction ....................................................................................................................................... 6
1.1 Current Transformer Circuits .............................................................................................................. 6
1.2 External Resistors.............................................................................................................................. 6
1.3 Description ........................................................................................................................................ 6
1.4 Ordering Options ............................................................................................................................... 7
1.5 Functional Diagram ............................................................................................................................ 8
1.6 Terminal Diagram .............................................................................................................................. 9
1.6.1 Terminal Diagram with Control Push Buttons ........................................................................ 9
Section 2: Hardware Description ...................................................................................................................... 10
2.1 General ........................................................................................................................................... 10
2.2 Front Fascia .................................................................................................................................... 11
2.2.1 Front Fascia with Control Push Buttons ............................................................................... 11
2.3 Start Motor/Stop Motor ..................................................................................................................... 11
2.4 Power Supply Unit (PSU) ................................................................................................................. 12
2.5 Connectors ...................................................................................................................................... 12
2.5.1 Connectors without Temperature Inputs .............................................................................. 13
2.5.2 Connectors with Temperature Inputs ................................................................................... 13
2.6 Relay Information ............................................................................................................................ 14
2.7 Operator Interface............................................................................................................................ 15
2.7.1 Liquid Crystal Display (LCD) ............................................................................................... 15
2.7.2 LCD Indication ................................................................................................................... 15
2.7.3 Standard Keys ................................................................................................................... 16
2.7.4 Protection Healthy LED ...................................................................................................... 16
2.7.5 Indication LEDs .................................................................................................................. 16
2.8 Current Inputs.................................................................................................................................. 17
2.9 Binary Inputs ................................................................................................................................... 18
2.10 Binary Outputs (Output Relays) ........................................................................................................ 18
2.11 Virtual Input/Outputs ........................................................................................................................ 19
2.12 Self Monitoring ................................................................................................................................ 20
2.12.1 Protection Healthy/Defective ............................................................................................... 21
Section 3: Protection Functions ........................................................................................................................ 22
3.1 Thermal Protection .......................................................................................................................... 22
3.1.1 Thermal Protection: Overload (49) ...................................................................................... 24
3.1.2 Thermal Protection: Stall Protection (14) ............................................................................. 27
3.1.3 Thermal Protection: Start Protection (48, 66) ....................................................................... 28
3.1.4 Thermal Protection: Phase Unbalance (46) ......................................................................... 30
3.2 Current Protection: Undercurrent (37) ............................................................................................... 33
3.3 Current Protection: Phase Overcurrent (50, 51) ................................................................................ 33
3.3.1 Instantaneous Overcurrent Protection (50) .......................................................................... 33
3.3.2 Time Delayed Overcurrent Protection (51) .......................................................................... 34
3.4 Current Protection: Derived Earth Fault (50N, 51N) ........................................................................... 35
3.4.1 Instantaneous Derived Earth Fault Protection (50N) ............................................................ 35
3.4.2 Time Delayed Derived Earth Fault Protection (51N) ............................................................. 36
3.5 Current Protection: Measured Earth Fault (50G, 51G) ....................................................................... 36
3.5.1 Instantaneous Measured Earth Fault Protection (50G) ......................................................... 36
3.5.2 Time Delayed Measured Earth Fault Protection (51G) ......................................................... 37
Section 4: Supervision Functions ...................................................................................................................... 38
4.1 Break Capacity Limit (50BCL) .......................................................................................................... 38
4.2 Anti-Backspin (81B) ......................................................................................................................... 39
4.3 Phase Reversal (46 PH REV) .......................................................................................................... 40
4.4 Trip Circuit Supervision (74TCS) ...................................................................................................... 41
4.5 Close Circuit Supervision (74CCS) ................................................................................................... 41
4.6 Circuit Breaker Failure (50BF) .......................................................................................................... 42
4.7 Temperature Inputs (TEMP) ............................................................................................................. 43