Siemens manual Figure A-1Hardware Structure of the 7SA511 Relay

7SA511 Line Protection RelayMethod of Operation

A.11.2 Determination of the Faulted Phase	A-61
A.11.3 Directional Determination	A-61
A.11.4 Ground Fault Location	A-63
A.12 High-Resistance Ground Fault Protection for Grounded Systems (Optional)	A-65
A.12.1 Directional Ground Fault Overcurrent Protection with Nondirectional Backup ...	A-66
A.12.2 Directional Comparison Ground Fault Protection	A-67
A.12.3 Non-Directional Inverse Time Ground Fault Protection	A-68
A.13 Automatic Reclose (Optional)	A-69
A.13.1 Selectivity During Automatic Reclose	A-71
A.13.2 Treatment of Evolving Faults	A-73
A.13.3 Treatment of Multiple Single-Phase Faults	A-73
A.13.4 Multi-Shot Automatic Reclose	A-74
A.13.5 Manual Close Onto Fault	A-74
A.13.6 External Automatic Reclose System	A-75
A.13.7 External Control of the Internal Automatic Reclose	A-76
A.13.8 Interconnecting Two Automatic Reclose Relays	A-77
A.14 Fault Locating	A-78
A.15 Ancillary Functions	A-79
A.15.1 LEDs and Binary Outputs (Signal Relays)	A-79
A.15.2 Digital Communications	A-79
A.15.3 Target Logs	A-80
A.15.4 Waveform Capture	A-80
A.15.5 Measured Values and Load Data	A-80
A.15.6 Self-Diagnostics	A-80
List of Figures
Figure A-1Hardware Structure of the 7SA511 Relay	A-6
Figure A-2. Ground Current Detector Characteristic	A-9
Figure A-3.Impedance Fault Detection Characteristic	A-11
Figure A-4. Voltage Controlled Overcurrent Fault Detection Characteristic	A-13
Figure A-5. Phase-to-Phase Short Circuit Loop	A-16
Figure A-6. Phase-to-Ground Short Circuit Loop	A-17
Figure A-7. Ground Fault in an Ungrounded System	A-20
Figure A-8.Phase-to-Phase Fault Resistance	A-25
Figure A-9.Phase-to-Ground Fault Resistance	A-26
Figure A-10.Ground Fault on a Parallel Line	A-27
Figure A-11. Reference Voltages for Directional Determination	A-28
Figure A-12. Relay 7SA511, Directional Characteristics	A-29
Figure A-13.Directional Characteristic with Source Impedance and No Load Transport	A-30
Figure A-14.Voltage Phasors and Directional Characteristics for a Loaded Line	A-31
Figure A-15. Tripping Characteristics	A-34
Figure A-16. Logic Diagram of Distance Protection Tripping	A-35
Figure A-17. Logic Diagram of the Switch-Onto-Fault Protection	A-36

A-2 July 27, 1995