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Transient earth-fault relay 7SN71 Instruction Manual March 1997...
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Transient earth-fault relay 7SN71 Instruction Manual Order No.: E50410-A0007-U501-A1-7691 Version March 1997 Siemens AG 1997...
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Trade marks Copyright Microsoft and MS-DOS are registered trade marks, The reproduction, transmission or use of this document Windows is a registered trade mark of Microsoft or its contents is not permitted without express written Corporation. All other brand or product names may be authority.
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Warning be referred to the local Siemens sales office. Dangerous voltages may occur in cer qualified person is one who is familiar with the...
Instruction Manual Order No.: E50410-A0007-U501-A1-7691 Application Earth fault directional determination The highly sensitive tansient earth-fault relay 7SN71 This charging process is bound up with a strong cur determines the direction of transient and continuous rent surge (starting oscillation). earth faults in systems with isolated neutral, in sy...
Application Transient earth-fault relay 7SN71 Instruction Manual Order No.: E50410-A0007-U501-A1-7691 At measuring point A, as a result of the transformer The displacement voltage V thereupon also returns summation circuit, the earth current of the faulted line to zero. In earthed systems this takes place after a...
Application Transient earth-fault relay 7SN71 Instruction Manual Order No.: E50410-A0007-U501-A1-7691 red LED forwards direction" yellow LED reverse direction" no indication Figure 1.3 Detection of fault location 1 - 3 Siemens AG March 1997...
Application Transient earth-fault relay 7SN71 Instruction Manual Order No.: E50410-A0007-U501-A1-7691 Functions and features D Device versions for panel surface mounting or D Optional suppression of switching operations flush mounting D Connection to 230 V AC D Bidirectional measurement, indication and signal...
Method of operation Transient earth-fault relay 7SN71 Instruction Manual Order No.: E50410-A0007-U501-A1-7691 Method of operation Current and voltage input (see figure 2.1) The summation current of the cable-type CT or of the In order to prevent incorrect signalling during swit...
Method of operation Transient earth-fault relay 7SN71 Instruction Manual Order No.: E50410-A0007-U501-A1-7691 Reset = 1 A I> = 5 A I> & V> "Release" & V> Continous earth fault V> 0...70 ms 2...0 s Figure 2.1 Current and voltage input...
Method of operation Transient earth-fault relay 7SN71 Instruction Manual Order No.: E50410-A0007-U501-A1-7691 Evaluating logic (see figure 2.2) Once the set current and voltage memories have LED is also activated , once the signals for directio been released and evaluated , the memories for...
Method of operation Transient earth-fault relay 7SN71 Instruction Manual Order No.: E50410-A0007-U501-A1-7691 Suppression of switching operations The front plug t " is used to enable or disable the If the front plug t " is inserted, switching operations delay time for control of the displacement voltage in isolated systems are not indicated or signalled.
Operating instructions Transient earth-fault relay 7SN71 Instruction Manual Order No.: E50410-A0007-U501-A1-7691 Operating instructions Safety precuations All safety precautions which apply for work in electri cal installations are to be observed during commissio ning. Connection to auxiliary power supply Figure 3.1 shows the connection to a current transfor nected to terminal 3 (1B1).
Operating instructions Transient earth-fault relay 7SN71 Instruction Manual Order No.: E50410-A0007-U501-A1-7691 Connection to auxiliary power supply Connection is either made to the 230 V AC mains or between two phases (100 V) of the v.t.s. Connection to the station battery is also possible (see figure 3.2).
Test equipment 7VP83 serves to test the transient the test object ic connected to test equipment 7VP83 earth-fault relay 7TH2300-0 / 7SN70 and 7SN71. as shown in figure 3.3. The test equipment operates at 230 V AC. Test current I...
If the pushbutton is pressed to reverse" (>100 ms), the yellow "LED " of 7SN71 must light up. In ad 3.5.4 Continuous earth-fault signal dition, the reverse" signal (relay contact) must be released.
Technical Data Transient earth-fault relay 7SN71 Instruction Manual Order No.: E50410-A0007-U501-A1-7691 Technical Data Table 4.1 Technical Data Measuring circuit Rated voltage V 100/110 V AC Rated current I 1 or 5 A Rated frequency f 50 Hz Thermal rating in current path, continuous...
Technical Data Transient earth-fault relay 7SN71 Instruction Manual Order No.: E50410-A0007-U501-A1-7691 Ordering code / MFLB Table 4.2 Selection and ordering data Order number Transient earth-fault relay 7SN71 7SN7100 - j j A 0 0 Auxiliary voltage V 100 to 110/230 V AC, 50 Hz...
Instruction Manual Order No.: E50410-A0007-U501-A1-7691 Connection diagrams A.1.1 Connection diagram of the 7SN71 (panel surface mounting with AC power supply unit) See figure A.5.4 on page A - 2. A.1.2 Connection diagram of the 7SN71 (panel surface mounting with DC power supply unit) See figure A.5.5 on page A - 3.
Appendix Transient earth-fault relay 7SN71 Instruction Manual Order No.: E50410-A0007-U501-A1-7691 Figure A.5.4 Connection diagram of the 7SN71 (panel surface mounting with AC power supply unit) A - 2 Siemens AG March 1997...
Appendix Transient earth-fault relay 7SN71 Instruction Manual Order No.: E50410-A0007-U501-A1-7691 Figure A.5.5 Connection diagram of the 7SN71 (panel surface mounting with DC power supply unit) A - 3 Siemens AG March 1997...
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Appendix Transient earth-fault relay 7SN71 Instruction Manual Order No.: E50410-A0007-U501-A1-7691 A - 4 Siemens AG March 1997...
INDEX Transient earth-fault relay 7SN71 - Instruction Manual Order No.: E50410-A0007-U501-A1-7691 Application, 1 - 1 Panel flush mounting, 5 - 1 Panel suface mounting, 5 - 2 Connection diagrams, A - 1 Connection to auxiliary power supply, 3 - 1, 3 - 2...
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INDEX Transient earth-fault relay 7SN71 - Instruction Manual Order No.: E50410-A0007-U501-A1-7691 X - II Siemens AG March 1997...
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Telephone no. Suggestions Corrections for document order no. version Transient earth-fault relay 7SN71 E50410-A0007-U501-A1-7691 March 1997 Instruction manual...
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Siemens AG, EV S, Power Substation Control and Power System Protection PO Box 48 06 Transmission D-90026 Nuremberg and Distribution Federal Republic of Germany Order No.: E50410-A0007-U501-A1-7691 Siemens Aktiengesellschaft Printed in Germany...