Table of Contents
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Contents
Document Release History....................................................................................................................1
Software Revision History.....................................................................................................................1
Contents ..................................................................................................................................................2
Section 1: Common Functions .............................................................................................................5
1.1 Overview ...................................................................................................................................5
1.2 Before Testing...........................................................................................................................5
1.2.1
Safety ...........................................................................................................................5
1.2.2
Sequence of Tests .......................................................................................................5
1.2.3
Test Equipment ............................................................................................................6
1.2.4
Precautions ..................................................................................................................6
1.2.5
Applying Settings .........................................................................................................7
1.3 Tests .........................................................................................................................................8
1.3.1
Inspection .....................................................................................................................8
1.3.2
Secondary Injection Tests............................................................................................8
1.3.3
Primary Injection Tests.................................................................................................8
1.3.4
Putting into Service ......................................................................................................8
1.4 AC Energising Quantities..........................................................................................................9
1.5 Binary Inputs ...........................................................................................................................10
1.6 Binary Outputs ........................................................................................................................11
1.7 Relay Case Shorting Contacts................................................................................................11
Section 2: Protection Functions .........................................................................................................12
2.1 Biased Differential (87BD, 87HS) ...........................................................................................14
2.1.1
Secondary Injection Testing.......................................................................................14
2.1.2
Primary Injection Testing............................................................................................17
2.1.3
Phase Overcurrent (50, 51)........................................................................................18
2.1.4
2.1.5
Inverse Time Overcurrent (51) .................................................................................19
2.2 Derived Earth fault (50N,51N).................................................................................................21
2.2.1
2.2.2
Inverse Time Overcurrent (51N) ..............................................................................22
2.2.3
ANSI Reset.................................................................................................................23
2.3 Measured Earth fault (50G, 51G)............................................................................................24
2.3.1
2.3.2
Inverse Time Overcurrent (51G) ..............................................................................25
2.3.3
ANSI Reset.................................................................................................................26
2.4 Restricted Earth fault (64H) ..................................................................................................27
2.5 Open Circuit (46BC)..............................................................................................................29
2.6 Negative Phase Sequence Overcurrent (46NPS) ..................................................................31
2.6.1
2.6.2
Inverse Time NPS Overcurrent (46IT) .....................................................................32
2.7 Undercurrent (37, 37G).........................................................................................................34
2.7.1
37-n Elements ............................................................................................................34
2.7.2
37G-n Elements .........................................................................................................35
2.8 Thermal Overload (49)............................................................................................................36
2.9 Under/Over Voltage (27/59)...................................................................................................38
2.9.2
Undervoltage Guard (27/59UVG) ..............................................................................40
2.10 Neutral Over Voltage (59N) ..................................................................................................41
2.10.1 Definite Time (59NDT) ...............................................................................................42
2.10.2 Inverse Time (59NIT) .................................................................................................42
©2010 Siemens Protection Devices Limited
7SR242 Duobias Commissioning & Maintenance Guide
(50) ...............................................................................19
(50N).............................................................................22
(50G).............................................................................25
(46DT) ..................................................................32
Chapter 6 Page 2 of 57
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