Siemens 7UT51 Instruction Manual page 6

Contents
8.4.2 Inverse Time Element (51) ....................................................................................................................... 101
8.5 Reset Time Delay .....................................................................................................................................101
8.6 Overcurrent Protection during Manual Close of Breaker .......................................................................... 102
8.7 Events and Actions...................................................................................................................................106
9 Thermal Overload Protection (49-1, 49-2) ................................................................................. 107
9.1 Method of Operation.................................................................................................................................107
9.2 Normal Operational Status ....................................................................................................................... 108
9.3 Pickup Characteristic and Warning Levels ...............................................................................................108
9.3.1 Maximum Continuous Overload Current .................................................................................................. 108
Time Constant τ .......................................................................................................................................................108
9.3.2
9.3.3 Warning Alarm Levels............................................................................................................................... 109
9.3.4 Temperature Rise Calculation Method ..................................................................................................... 109
9.4 Logical Events and Actions ...................................................................................................................... 111
10 Tank Leakage Protection (64T) .................................................................................................. 113
10.1 Method of Operation................................................................................................................................. 113
10.2 Normal Operational Status ....................................................................................................................... 113
10.3 Pickup and Dropout Levels....................................................................................................................... 114
10.4 Time Delays.............................................................................................................................................. 115
10.5 Events and Actions................................................................................................................................... 115
11 Protecting an Additional Device or Equipment ........................................................................ 117
12 Protection Self-Monitoring ......................................................................................................... 119
12.1 Self-Monitor Signal Contact ...................................................................................................................... 119
12.2 Internal Self-Monitoring ............................................................................................................................ 119
12.2.1 Reset of LEDs .......................................................................................................................................... 119
12.2.2 Change of Parameter Set......................................................................................................................... 119
12.2.3 Software-Hardware Mismatch .................................................................................................................. 119
12.2.4 Data Buffer Invalid or Overflowing ............................................................................................................ 119
12.2.5 Memory Monitoring (Checksum) .............................................................................................................. 119
12.2.6 Processor .................................................................................................................................................120
12.2.7 Internal Power Supplies............................................................................................................................ 120
12.2.8 Analog/Digital Converters .........................................................................................................................120
12.2.9 Trip Circuits............................................................................................................................................... 120
12.3 Monitoring of Supply Power...................................................................................................................... 120
12.4 Monitoring of CT Circuits .......................................................................................................................... 120
12.4.1 Current Symmetry ....................................................................................................................................120
12.4.2 Current Summation .................................................................................................................................. 121
12.5 Events and Actions...................................................................................................................................122
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7UT51 v3
PRIM-2330C