Siemens 3VA1 100 A Manual page 6

Table of contents
2.6 Protection system ...............................................................................................................69
2.6.1 Description of functions ......................................................................................................70
2.6.2 Characteristic curves ..........................................................................................................72
2.6.3 Guide to setting the tripping characteristic ..........................................................................74
2.6.4 Overload protection (L) .......................................................................................................76
2.6.5 Short-time delayed short-circuit protection (S) ....................................................................77
2.6.6 Instantaneous short-circuit protection (I) .............................................................................77
2.6.7 Ground-fault protection (G) .................................................................................................77
2.6.8 Neutral conductor protection (N) .........................................................................................78
2.6.9 Zone-selective interlocking ZSI ...........................................................................................81
2.7 Thermal-magnetic trip unit ..................................................................................................84
2.7.1 Thermal trip unit (L) ............................................................................................................84
2.7.2 Magnetic trip unit with short-circuit protection (I) .................................................................84
2.7.3 Application cases and trip unit types ...................................................................................85
2.8 Electronic trip unit ...............................................................................................................86
2.8.1 Connections .......................................................................................................................87
2.8.2 Protection functions ............................................................................................................88
2.8.3 Operator controls ...............................................................................................................90
2.8.4 Load acceptance and load shedding - load management ..................................................100
2.8.5 Measuring with a Rogowski coil ........................................................................................101
3 Applications............................................................................................................................... 105
3.1 Line protection applications of 3VA molded case circuit breakers ......................................105
3.1.1 Variants............................................................................................................................106
3.1.1.1 Thermal-magnetic trip units ..............................................................................................106
3.1.1.2 Electronic trip units ...........................................................................................................110
3.1.2 Overview of 3VA molded case circuit breakers in line protection applications ....................124
3.2 Use of the 3VA1 breaker as a switch disconnector ...........................................................126
3.2.1 Overview of 3VA1 as switch disconnectors .......................................................................130
3.2.2 Upstream protection of switch disconnectors ....................................................................130
3.3 DC network applications of the 3VA molded case circuit breaker ......................................132
3.3.1 Introduction ......................................................................................................................132
3.3.2 Variants............................................................................................................................133
3.3.3 Breaking capacity with direct current.................................................................................134
3.3.4 Recommended circuit configurations for DC systems .......................................................135
3.4 400 Hz network applications of 3VA molded case circuit breakers ....................................136
3.5 IT system applications of 3VA molded case circuit breakers .............................................138
3.5.1 Selection criteria for 3VA molded case circuit breakers .....................................................138
3.5.2 Fault situation ...................................................................................................................139
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3VA molded case circuit breakers
Manual, 04/2015, A5E03603177010-02