Section 1: Introduction ............................................................................................................................................. 8

Section 2: Hardware Description ............................................................................................................................ 18

2.1 General ................................................................................................................................................. 18

2.2 Case...................................................................................................................................................... 19

2.3 Front Cover ........................................................................................................................................... 20

2.4 Power Supply Unit (PSU) ...................................................................................................................... 21

2.5 Operator Interface/ Fascia .................................................................................................................... 22

2.6 Current Inputs ....................................................................................................................................... 25

2.7 Voltage Inputs ....................................................................................................................................... 25

2.8 Binary Inputs ......................................................................................................................................... 25

2.9 Binary Outputs (Output Relays) ............................................................................................................ 26

2.10 Virtual Input/Outputs ............................................................................................................................. 27

2.11 Self Monitoring ...................................................................................................................................... 28

2.11.1

Protection Healthy/Defective ................................................................................................... 30

Section 3: Protection Functions ............................................................................................................................. 31

3.1 Current Protection: Phase Overcurrent (67, 51, 50) .............................................................................. 31

3.1.1

Directional Control of Overcurrent Protection (67) - 7SR12 ................................................... 31

3.1.2

Instantaneous Overcurrent Protection (50) ............................................................................. 32

3.1.3

Time Delayed Overcurrent Protection (51).............................................................................. 33

3.1.4

Current Protection: Voltage Controlled Overcurrent (51V) - 7SR12 ........................................ 35

3.2 Current Protection: Derived Earth Fault (67N, 51N, 50N) ..................................................................... 36

3.2.1

Directional Control of Derived Earth Fault Protection (67N) - 7SR12 ..................................... 36

3.2.2

Instantaneous Derived Earth Fault Protection (50N) ............................................................... 37

3.2.3

Time Delayed Derived Earth Fault Protection (51N) ............................................................... 37

3.3 Current Protection: Measured Earth Fault (67G, 51G, 50G) ................................................................. 39

3.3.1

Directional Control of Measured Earth Fault Protection (67G) - 7SR12 ................................. 39

3.3.2

Instantaneous Measured Earth Fault Protection (50G) ........................................................... 40

3.3.3

Time Delayed Measured Earth Fault Protection (51G) ........................................................... 41

3.4 Current Protection: Sensitive Earth Fault (67SEF, 51SEF, 50SEF) ...................................................... 42

3.4.1

Directional Control of Sensitive Earth Fault Protection (67SEF) - 7SR12 .............................. 42

3.4.2

Instantaneous Sensitive Earth Fault Protection (50SEF) ........................................................ 43

3.4.3

Time Delayed Sensitive Earth Fault Protection (51SEF) ........................................................ 45

3.5 Current Protection: High Impedance Restricted Earth Fault - (64H) ..................................................... 47

3.6 Current Protection: Cold Load (51c) ..................................................................................................... 47

3.7 Current Protection: Negative Phase Sequence Overcurrent - (46NPS) ................................................ 48

3.8 Current Protection: Under-Current (37) ................................................................................................. 49

3.9 Current Protection: Thermal Overload (49) ........................................................................................... 50

3.10 Current Protection: Line Check 50LC, 50G LC and 50SEF LC - Only software option 'C' ................... 51

3.11 Current Protection: Arc Flash Detector (50 AFD) .................................................................................. 53

3.12 Voltage Protection: Phase Under/Over Voltage (27/59) - 7SR12 ......................................................... 54

3.13 Voltage Protection: Negative Phase Sequence Overvoltage (47) - 7SR12 .......................................... 55

3.14 Voltage Protection: Neutral Overvoltage (59N) - 7SR12 ...................................................................... 55

3.15 Voltage Protection: Under/Over Frequency (81) - 7SR12 .................................................................... 57

3.16 Power Protection: Power (32) - 7SR12 ................................................................................................ 58

3.17 Power Protection: Sensitive Power (32S) - 7SR12 .............................................................................. 59

3.18 Power Protection: Power Factor (55) - 7SR12 ..................................................................................... 60

Section 4: Control & Logic Functions ..................................................................................................................... 61

4.1 Auto-Reclose (79) Optional Function .................................................................................................... 61

4.1.1

Overview ................................................................................................................................. 61

4.1.2

Auto Reclose sequences ........................................................................................................ 62

4.1.3

Autoreclose Prot'n Menu ......................................................................................................... 63

4.1.4

Autoreclose Config Menu ........................................................................................................ 63

4.1.5

P/F Shots sub-menu ............................................................................................................... 65

4.1.6