Table Of Contents - Siemens 7SR242 Duobias Technical Manual

Contents
Section 1: Introduction ..................................................................................................................... 7
Current Transformer Circuits........................................................................................................ 7
External Resistors ....................................................................................................................... 7
Fibre Optic Communication ......................................................................................................... 7
Front Cover ................................................................................................................................. 7
Section 2: Hardware Description.................................................................................................... 15
2.1 General .............................................................................................................................. 15
2.2 Case .................................................................................................................................. 15
2.3 Front Cover ........................................................................................................................ 16
2.4 Power Supply Unit (PSU) ................................................................................................... 16
2.5 Operator Interface/ Fascia .................................................................................................. 16
2.6 Current Inputs .................................................................................................................... 19
2.7 Voltage Input ...................................................................................................................... 19
2.8 Binary inputs ...................................................................................................................... 19
2.9 Binary outputs (Output Relays) ........................................................................................... 20
2.10 Virtual Input/Outputs........................................................................................................... 21
2.11 Self Monitoring ................................................................................................................... 22
2.11.1 Protection Healthy/Defective .................................................................................. 22
Section 3: Protection Functions ..................................................................................................... 23
3.1 Current Protection: Differential Protection ........................................................................... 23
3.1.1 ICT ........................................................................................................................ 23
3.1.2 Overall Biased Differential (87BD) .......................................................................... 24
3.1.3 87HS ..................................................................................................................... 26
3.2 Current Protection: Phase Overcurrent (51, 50) .................................................................. 28
3.2.1 Instantaneous Overcurrent Protection (50) ............................................................. 28
3.2.2 Time Delayed Overcurrent Protection (51) ............................................................. 29
3.3 Current Protection: Derived Earth Fault (50N, 51N) ............................................................ 30
3.3.1 Instantaneous Derived Earth Fault Protection (50N) ............................................... 30
3.3.2 Time Delayed Derived Earth Fault Protection (51N) ............................................... 31
3.4 Current Protection: Measured Earth Fault (50G, 51G) ........................................................ 32
3.4.1 Instantaneous Measured Earth Fault Protection (50G) ........................................... 32
3.4.2 Time Delayed Measured Earth Fault Protection (51G) ............................................ 33
3.5 Current Protection: High Impedance Restricted Earth Fault (64H) ....................................... 34
3.6 Open Circuit (46BC) ........................................................................................................... 35
3.7 Current Protection: Negative Phase Sequence Overcurrent (46NPS) ................................. 36
3.8 Current Protection: Under-Current (37, 37G) ...................................................................... 37
3.9 Current Protection: Thermal Overload (49) ......................................................................... 38
3.10 Voltage Protection: Over Fluxing (24) ................................................................................. 40
3.11 Voltage Protection: Under/Over Voltage (27/59) ................................................................. 42
3.12 Voltage Protection: Neutral Overvoltage (59N) ................................................................... 43
3.13 Voltage Protection: Under/Over Frequency (81) ................................................................. 44
Section 4: Control & Logic Functions ............................................................................................ 45
4.1 Quick Logic ........................................................................................................................ 45
Section 5: Supervision Functions .................................................................................................. 47
5.1 Circuit Breaker Failure (50BF) ............................................................................................ 47
5.2 Trip/Close Circuit Supervision (74TCS/74CCS) .................................................................. 49
5.3 Inrush Detector (81HBL2) ................................................................................................... 50
©2015 Siemens Protection Devices Limited
Chapter 1) 7SR242 Duobias Description Of Operation
Chapter 1 Page 3 of 60