Siemens 7SR105 Rho - Protection Functions

7SR105 Rho Description Of Operation
©2018 Siemens Protection Devices Chapter 1 Page 4 of 57
List of Figures
Figure 1-1
Functional Diagram of 7SR105 Rho Motor Protection Relay ................................................................ 8
Figure 2-1 7SR105 Rho Motor Protection Relay with control push buttons .......................................................... 11
Figure 2-2 7SR105 Rho Motor Protection Relay Connectors without Temperature Inputs .................................... 13
Figure 2-3 7SR105 Rho Motor Protection Relay Connectors with Temperature Inputs ......................................... 13
Figure 2-4 Relay Rating Label ........................................................................................................................... 14
Figure 2-5 Fascia Relay Rating Label ................................................................................................................ 14
Figure 2-6 Safety Symbols ................................................................................................................................ 15
Figure 2-7 Close up of Relay Identifier ............................................................................................................... 15
Figure 2-9 Binary Input Logic ............................................................................................................................. 18
Figure 2-10 Binary Output Logic .......................................................................................................................... 19
Figure 2-11 Start-up Counter Meter ..................................................................................................................... 20
Figure 2-12 Unexpected Restarts Lockout Text .................................................................................................... 20
Figure 2-13 Start-up Events ................................................................................................................................ 21
Figure 3.1-1 Thermal Overload Heating and Cooling Characteristic ....................................................................... 22
Figure 3-2 Logic Diagram: Motor Thermal Overload Protection (49) .................................................................... 25
Figure 3.1-3 Application of Thermal Overload Time Constants .............................................................................. 26
Figure 3-4 Stall Protection (14) .......................................................................................................................... 27
Figure 3-5 Number of Starts Protection (66) ....................................................................................................... 28
Figure 3-6 Start Time Supervision (48) .............................................................................................................. 29
Figure 3-7 Inverse Time Characteristic for Unbalance Protection ........................................................................ 30
Figure 3-8 Logic Diagram : NPS Phase Unbalance (46NPS) .............................................................................. 31
Figure 3-9 Logic Diagram: Phase Difference Phase Unbalance (46PD) .............................................................. 32
Figure 3-10 Logic Diagram: Undercurrent Detector (37) ....................................................................................... 33
Figure 3-11 Logic Diagram: Instantaneous Overcurrent Element .......................................................................... 34
Figure 3-12 Logic Diagram: Time Delayed Overcurrent Element ........................................................................... 35
Figure 3-13 Logic Diagram: Derived Instantaneous Earth Fault Element ............................................................... 35
Figure 3-14 Logic Diagram: Derived Time Delayed Earth Fault Protection ............................................................ 36
Figure 3-15 Logic Diagram: Measured Instantaneous Earth-fault Element ............................................................ 37
Figure 3-16 Logic Diagram: Measured Time Delayed Earth Fault Element (51G) .................................................. 37
Figure 4-1 Logic Diagram: Breaking Capacity Limit (50BCL) ............................................................................... 38
Figure 4-2 Logic Diagram: Anti-Backspin Protection (81B) .................................................................................. 39
Figure 4-3 Logic Diagram: Phase Reversal Detection (46 PH REV) .................................................................... 40
Figure 4-4 Logic Diagram: Trip Circuit Supervision Feature (74TCS) .................................................................. 41
Figure 4-5 Logic Diagram: Close Circuit Supervision Feature (74CCS) ............................................................... 41
Figure 4-6 Logic Diagram: Circuit Breaker Fail Protection (50BF) ....................................................................... 42
Figure 5-1 Logic Diagram: Circuit Breaker Status ............................................................................................... 45
Figure 5-2 Logic Diagram: Motor Control ........................................................................................................... 46
Figure 5-3 Sequence Diagram: Quick Logic PU/DO Timers (Counter Reset Mode Off) ........................................ 47
Figure 6-1 Communication to Front USB Port .................................................................................................... 49
Figure 6-2 Connect Icon .................................................................................................................................... 49
Figure 6-3 Port Selection in Connection Manager .............................................................................................. 50
Figure 6-4 System Information Icon ................................................................................................................... 50
Figure 6-5 System Information Icon ................................................................................................................... 51
Figure 6-6 Communication to Multiple Devices from Control System using RS485 .............................................. 52
List of Tables
Table 2-1
Summary of 7SR105 Rho Motor Protection Relay Configurations....................................................... 10
Table 3-1 Application of Thermal Time Constants ............................................................................................. 22
Table 6-1 Operation Mode ............................................................................................................................... 55