Siemens SIPROTEC 7SS525 V3.3 User Manual

Table of Contents
ix
7SS52 V4 Manual
C53000-G1176-C182-3
5 Functions............................................................................................................................................ 91
5.1 Busbar Protection................................................................................................................. 92
5.1.1 Mode of operation ................................................................................................................ 92
5.1.1.1 Basic Principle...................................................................................................................... 92
5.1.1.2 Algorithm with Instantaneous Values ................................................................................... 94
5.1.1.3 Separate Evaluation of Half-Cycles...................................................................................... 96
5.1.1.4 Evaluation of the Initial Values ............................................................................................. 99
5.1.1.5 Algorithm with Filtered Values............................................................................................ 100
5.1.1.6 Summary of the Measuring Method ................................................................................... 100
5.1.2 Isolator Replica................................................................................................................... 101
5.1.3 Bus Coupler Variants.......................................................................................................... 103
5.1.3.1 Bus Couplers with One Current Transformer ..................................................................... 103
5.1.3.2 Bus Couplers with Two Current Transformers ................................................................... 104
5.1.3.3 Bus Couplers without Circuit Breaker................................................................................. 104
5.1.3.4 Bus Couplers with more than 5 Isolators............................................................................ 104
5.1.3.5 Combi-Coupler ................................................................................................................... 104
5.1.3.6 Transfer Busbars................................................................................................................ 105
5.1.3.7 Transfer Busbar With Inside Transformers......................................................................... 107
5.1.3.8 Special Cases of Transfer Busbar Operation..................................................................... 107
5.1.4 Setting Notes...................................................................................................................... 108
5.1.5 Settings for the Central Unit ............................................................................................... 111
5.2 Check Zone ........................................................................................................................ 112
5.2.1 Mode of operation .............................................................................................................. 112
5.2.2 Setting Notes...................................................................................................................... 113
5.2.3 Settings for the Central Unit ............................................................................................... 113
5.3 Circuit Breaker Failure Protection....................................................................................... 114
5.3.1 Characteristics for the Circuit Breaker Failure Protection................................................... 114
5.3.2 Setting Notes...................................................................................................................... 115
5.3.3 Settings for the Central Unit ............................................................................................... 116
5.3.4 List of Information from the Central Unit............................................................................. 116
5.3.5 Bay-Specific Functions (BU)............................................................................................... 117
5.3.5.1 Triggering and Releasing the Breaker Failure Protection................................................... 117
5.3.5.2 Circuit Breaker Failure Protection during a Feeder Short-Circuit ....................................... 119
5.3.5.3 Circuit Breaker Failure Protection for Busbar Faults .......................................................... 126
5.3.5.4 Failure of the Bus Coupler Circuit Breaker......................................................................... 127
5.3.5.5 Circuit Breaker Not Ready.................................................................................................. 127
5.3.6 Setting Notes...................................................................................................................... 128
5.3.7 Settings for the Central Unit ............................................................................................... 132
5.3.8 List of Information from the Central Unit............................................................................. 133
5.3.9 List of Information from the Bay Unit.................................................................................. 134
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Siemens SIPROTEC 7SS525 V3.3 Specifications

General

Brand	Siemens
Model	SIPROTEC 7SS525 V3.3
Category	Power distribution unit
Language	English