Siemens 7SR21 Manual page 3

5.2 Current Transformer Supervision (60CTS).............................................................................35
5.3 Voltage Transformer Supervision (60VTS).............................................................................36
5.4 Trip-Circuit Supervision (74TCS) ............................................................................................37
5.4.1 Trip Circuit Supervision Connections .........................................................................37
5.5 Inrush Detector (81HBL2) .......................................................................................................39
5.6 Broken Conductor / Load Imbalance (46BC)..........................................................................39
5.7 Circuit-Breaker Maintenance ..................................................................................................39
List of Figures
Figure 1.1-1 Example Use of Alternative Settings Groups ......................................................................4
Figure 1.2-1 Example of Transformer Alarm and Trip Wiring ..................................................................5
Figure 1.2-2 - Binary Input Configurations Providing Compliance with EATS 48-4 Classes
ESI 1 and ESI 2 ...................................................................................................................7
Figure 1.4-1 LED configuration via the LED Matrix tab............................................................................8
Figure 1.4-2 LED configuration via the Settings \ OUTPUT CONFIG \ LED CONFIG menu ..................9
Figure 2.1-1 IEC NI Curve with Time Multiplier and Follower DTL Applied ...........................................10
Figure 2.1-2 IEC NI Curve with Minimum Operate Time Setting Applied ..............................................11
Figure 2.1-3 Reset Delay .......................................................................................................................12
Figure 2.4-1 General Form of DTL Operate Characteristic....................................................................14
Figure 2.4-2 Blocking Scheme Using Instantaneous Overcurrent Elements.........................................15
Figure 2.5-1 Sensitive Earth Fault Protection Application......................................................................16
Figure 2.6-1 Directional Characteristics ................................................................................................17
Figure 2.6-2 Phase Fault Angles............................................................................................................17
Figure 2.6-3 Application of Directional Overcurrent Protection..............................................................18
Figure 2.6-4 Feeder Fault on Interconnected Network ..........................................................................19
Figure 2.7-1 Earth Fault Angles .............................................................................................................20
Figure 2.8-1 Balanced and Restricted Earth-fault protection of Transformers ....................................21
Figure 2.8-2 Composite Overcurrent and Restricted Earth-fault Protection .........................................22
Figure 2.11-1 Thermal Overload Heating and Cooling Characteristic .............................................23
Figure 2.13-1 NVD Application...............................................................................................................25
Figure 2.13-2 NVD Protection Connections ...........................................................................................25
Figure 2.15-1 Load Shedding Scheme Using Under-Frequency Elements...........................................27
Figure 4.1-1 Sequence Co-ordination ....................................................................................................29
Figure 4.1-2 Example of Logic Application.............................................................................................31
Figure 4.2-1 Example Use of Quick Logic..............................................................................................32
Figure 5.1-1 - Circuit Breaker Fail ..........................................................................................................33
Figure 5.1-2 - Single Stage Circuit Breaker Fail Timing.........................................................................34
Figure 5.1-3 - Two Stage Circuit Breaker Fail Timing ............................................................................34
Figure 5.4-1:Trip Circuit Supervision Scheme 1 (H5) ............................................................................37
Figure 5.4-2:Trip Circuit Supervision Scheme 2 (H6) ............................................................................38
Figure 5.4-3:Trip Circuit Supervision Scheme 3 (H7) ............................................................................38
List of Tables
Table 2-1 Application of IDMTL Characteristics..............................................................12
Table 5-2 Determination of VT Failure (1 or 2 Phases) ....................................................36
Table 5-3 Determination of VT Failure (3 Phases) ..........................................................36
Table 5-4 Magnetic Inrush Bias...................................................................................39
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7SR21 & 7SR22 Argus Applications Guide
Chapter 7 Page 3 of 39