7SR21 & 7SR22 Argus Description of Operation
The copyright and other intellectual property rights in this document, and in any model or article produced from it
(and including any registered or unregistered design rights) are the property of Siemens Protection Devices
Limited. No part of this document shall be reproduced or modified or stored in another form, in any data retrieval
system, without the permission of Siemens Protection Devices Limited, nor shall any model or article be
reproduced from this document unless Siemens Protection Devices Limited consent.
While the information and guidance given in this document is believed to be correct, no liability shall be accepted
for any loss or damage caused by any error or omission, whether such error or omission is the result of
negligence or any other cause. Any and all such liability is disclaimed.
©2010 Siemens Protection Devices Limited
7SR21 Non-Directional
7SR22 Directional
Overcurrent Relay
Document Release History
This document is issue 2010/05. The list of revisions up to and including this issue is:
2010/05 Additional Comms modules option of (RS485 + IRIG-B) and (RS232 + IRIG-B) and
typographical revisions
2010/02 Document reformat due to rebrand
2009/09 Third Issue. Software revision 2435H80004/5 R4b-4
2008/07 Second issue. Software revision 2435H80004/5 R3d-3.
2008/03 First issue
Software Revision History
2009/09 2435H80004/5 R4b-4 CTS-I Supervision. Undercurrent 37G & 37SEF. Vx U/O
Voltage. 46BC U/C. Comms Settings. Waveform Storage
Settings. Fault Storage Settings. Energy Storage. Trip test
function. Local/Remote modes. Settings ranges extended.
Protocol changes.
2008/07 2435H80004/5R3d-3 Demand records. Optional DNP3.0 data comms.
2008/03 2435H80004/5R2c-2b First Release
7SR21 & 7SR22 Argus Description of Operation
©2010 Siemens Protection Devices Limited Chapter 1 Page 2 of 71
Contents
Document Release History ...................................................................................................................................... 1
Software Revision History........................................................................................................................................ 1
Contents .................................................................................................................................................................. 2
List of Figures .......................................................................................................................................................... 4
List of Tables............................................................................................................................................................ 5
Section 1: Introduction ............................................................................................................................................. 6
1 Current Transformer Circuits................................................................................................................... 6
2 External Resistors................................................................................................................................... 6
3 Fibre Optic Communication..................................................................................................................... 6
4 Front Cover ............................................................................................................................................. 6
Section 2: Hardware Description............................................................................................................................ 14
2.1 General ................................................................................................................................................. 14
2.2 Case...................................................................................................................................................... 14
2.3 Front Cover ........................................................................................................................................... 15
2.4 Power Supply Unit (PSU)...................................................................................................................... 15
2.5 Operator Interface/ Fascia .................................................................................................................... 15
2.6 Current Inputs ....................................................................................................................................... 18
2.7 Voltage Inputs ....................................................................................................................................... 18
2.8 Binary Inputs ......................................................................................................................................... 19
2.9 Binary Outputs (Output Relays) ............................................................................................................ 20
2.10 Virtual Input/Outputs ............................................................................................................................. 21
2.11 Self Monitoring ...................................................................................................................................... 21
2.11.1 Protection Healthy/Defective................................................................................................... 21
Section 3: Protection Functions ............................................................................................................................. 22
3.1 Current Protection: Phase Overcurrent (67, 51, 50).............................................................................. 22
3.1.1 Directional Control of Overcurrent Protection (67) – 7SR22 ................................................... 22
3.1.2 Instantaneous Overcurrent Protection (50) ............................................................................. 24
3.1.3 Time Delayed Overcurrent Protection (51).............................................................................. 25
3.2 Current Protection: Voltage Controlled Overcurrent (51V) – 7SR22 ..................................................... 27
3.3 Current Protection: Derived Earth Fault (67N, 51N, 50N) ..................................................................... 28
3.3.1 Directional Control of Derived Earth Fault Protection (67N) – 7SR22..................................... 28
3.3.2 Instantaneous Derived Earth Fault Protection (50N)............................................................... 29
3.3.3 Time Delayed Derived Earth Fault Protection (51N) ............................................................... 30
3.4 Current Protection: Measured Earth Fault (67G, 51G, 50G) ................................................................. 32
3.4.1 Directional Control of Measured Earth Fault Protection (67G) – 7SR22 ................................. 32
3.4.2 Instantaneous Measured Earth Fault Protection (50G)........................................................... 33
3.4.3 Time Delayed Measured Earth Fault Protection (51G) ........................................................... 34
3.5 Current Protection: Sensitive Earth Fault (67SEF, 51SEF, 50SEF)...................................................... 35
3.5.1 Directional Control of Sensitive Earth Fault Protection (67SEF) – 7SR22 .............................. 35
3.5.2 Instantaneous Sensitive Earth Fault Protection (50SEF) ........................................................ 36
3.6 Current Protection: High Impedance Restricted Earth Fault (64H) ....................................................... 38
3.7 Current Protection: Cold Load (51c) ..................................................................................................... 39
3.8 Current Protection: Negative Phase Sequence Overcurrent (46NPS) .................................................. 40
3.9 Current Protection: Under-Current (37, 37G & 37SEF)......................................................................... 41
3.10 Current Protection: Thermal Overload (49) ........................................................................................... 42
3.11 Voltage Protection: Phase Under/Over Voltage (27/59) - 7SR22.......................................................... 44
3.12 Voltage Protection: Negative Phase Sequence Overvoltage (47) – 7SR22 .......................................... 45
3.13 Voltage Protection: Neutral Overvoltage (59N) – 7SR22 ...................................................................... 46
3.14 Voltage Protection: Under/Over Frequency (81) – 7SR22 .................................................................... 47
Section 4: Control & Logic Functions ..................................................................................................................... 48
4.1 Auto-Reclose (79) ................................................................................................................................. 48
4.1.1 Overview................................................................................................................................. 48
4.1.2 Auto Reclose sequences ........................................................................................................ 50
4.2 Autoreclose Prot’n Menu....................................................................................................................... 51
4.3 Autoreclose Config Menu...................................................................................................................... 51
4.4 P/F Shots Sub-Menu............................................................................................................................. 53
4.5 E/F Shots Sub-Menu............................................................................................................................. 53
4.6 SEF Shots Sub-Menu ........................................................................................................................... 53
4.7 Extern Shots Sub-Menu ........................................................................................................................ 54
4.8 Manual Control...................................................................................................................................... 56
4.9 Circuit Breaker ...................................................................................................................................... 56
4.10 Quick Logic ........................................................................................................................................... 58
Section 5: Supervision Functions........................................................................................................................... 60
5.1 Circuit Breaker Failure (50BF) .............................................................................................................. 60
7SR21 & 7SR22 Argus Description of Operation
©2010 Siemens Protection Devices Limited Chapter 1 Page 3 of 71
5.2 VT Supervision (60VTS) – 7SR22 ........................................................................................................ 61
5.3 CT Supervision (60CTS & 60CTS-I) ..................................................................................................... 63
5.4 (60CTS-I) – 7SR21 & 7SR22 ................................................................................................................ 63
5.5 (60CTS) – 7SR22 ................................................................................................................................. 63
5.6 Broken Conductor (46BC)..................................................................................................................... 64
5.7 Trip Circuit Supervision (74TCS) .......................................................................................................... 64
5.8 Inrush Restraint (81HBL2) .................................................................................................................... 65
Section 6: Other Features...................................................................................................................................... 66
6.1 Data Communications........................................................................................................................... 66
6.2 CB Maintenance ................................................................................................................................... 66
6.2.1 Output Matrix Test .................................................................................................................. 66
6.3 Data Storage......................................................................................................................................... 67
6.3.1 General ................................................................................................................................... 67
6.3.2 Demand / Data Log................................................................................................................. 67
6.3.3 Event Records ........................................................................................................................ 67
6.3.4 Waveform Records. ................................................................................................................ 68
6.3.5 Fault Records.......................................................................................................................... 68
6.4 Metering ................................................................................................................................................ 68
6.5 Operating Mode .................................................................................................................................... 69
6.6 Control Mode ........................................................................................................................................ 69
6.7 Real Time Clock.................................................................................................................................... 70
6.7.1 Time Synchronisation - Data Communication Interface .......................................................... 70
6.7.2 Time Synchronisation – Binary Input ...................................................................................... 70
6.7.3 Time Synchronisation – IRIG-B (Optional) .............................................................................. 70
6.8 Settings Groups .................................................................................................................................... 70
6.9 Password Feature................................................................................................................................. 71
7SR21 & 7SR22 Argus Description of Operation
©2010 Siemens Protection Devices Limited Chapter 1 Page 4 of 71
List of Figures
Figure 1-1
Functional Diagram of 7SR21 Relay ...................................................................................8
Figure 1-2 Connections Diagram for 7SR21 Relay...............................................................................9
Figure 1-3 Functional Diagram of 7SR22 Relay .................................................................................12
Figure 1-4 Connection Diagram for 7SR22 Relay...............................................................................13
Figure 2.5-1 7SR21 with 3 + 8 LEDs in E6 Case...................................................................................15
Figure 2.5-2 7SR22 with 3 + 16 LEDs in E8 Case.................................................................................16
Figure 2.5-3 7SR22 with Function Keys and 3 + 8 LEDs in E8 Case....................................................16
Figure 2.8-1 Binary Input Logic ..............................................................................................................19
Figure 2.9-1 Binary Output Logic ...........................................................................................................20
Figure 3.1-1 Logic Diagram: Directional Overcurrent Element (67).......................................................23
Figure 3.1-2 Logic Diagram: Instantaneous Over-current Element .......................................................24
Figure 3.1-3 Logic Diagram: Time Delayed Overcurrent Element.........................................................26
Figure 3.2-1 Logic Diagram: Voltage Controlled Overcurrent Protection...............................................27
Figure 3.3-1 Logic Diagram: Derived Directional Earth Fault Element ..................................................29
Figure 3.3-2 Logic Diagram: Derived Instantaneous Earth Fault Element ............................................30
Figure 3.3-3 Logic Diagram: Derived Time Delayed Earth Fault Protection..........................................31
Figure 3.4-1 Logic Diagram: Measured Directional Earth Fault Protection ...........................................32
Figure 3.4-2 Logic Diagram: Measured Instantaneous Earth-fault Element..........................................33
Figure 3.4-3 Logic Diagram: Measured Time Delayed Earth Fault Element (51G)...............................34
Figure 3.5-1 Logic Diagram: SEF Directional Element (67SEF)............................................................35
Figure 3.5-2 Logic Diagram: SEF Instantaneous Element.....................................................................36
Figure 3.5-3 Logic Diagram: SEF Time Delayed Element (51SEF).......................................................37
Figure 3.6-1 Logic Diagram: High Impedance REF (64H) .....................................................................38
Figure 3.7-1 Logic Diagram: Cold Load Settings (51c)..........................................................................39
Figure 3.8-1 Logic Diagram: Negative Phase Sequence Overcurrent (46NPS)....................................40
Figure 3.9-1 Logic Diagram: Undercurrent Detector (37, 37G & 37SEF) ..............................................41
Figure 3.10-1 Logic Diagram: Thermal Overload Protection (49S)..................................................43
Figure 3.11-1 Logic Diagram: Under/Over Voltage Elements (27/59) .............................................44
Figure 3.12-1 Logic Diagram: NPS Overvoltage Protection (47) .....................................................45
Figure 3.13-1 Logic Diagram: Neutral Overvoltage Element............................................................46
Figure 3.14-1 Logic Diagram: Under/Over Frequency Detector (81) ...............................................47
Figure 4.1-1 Typical Auto Reclose Sequence with 3 Instantaneous and 1 Delayed trip .......................50
Figure 4.7-1 Basic Auto-Reclose Sequence Diagram ...........................................................................55
Figure 4.9-1 Logic Diagram: Circuit Breaker Status...............................................................................57
Figure 4.10-1 Sequence Diagram: Quick Logic PU/DO Timers (Counter Reset Mode Off)..................59
Figure 5.1-1 Logic Diagram: Circuit Breaker Fail Protection (50BF)......................................................60
Figure 5.2-1 Logic Diagram: VT Supervision Function (60VTS)............................................................62
Figure 5.4-1 Logic Diagram: CT Supervision Function (60CTS-I) – 7SR21 & 7SR22...........................63
Figure 5.5-1 Logic Diagram: CT Supervision Function (60CTS) – 7SR22 ............................................63
Figure 5.6-1 Logic Diagram: Broken Conductor Function (46BC) .........................................................64
Figure 5.7-1 Logic Diagram: Trip Circuit Supervision Feature (74TCS) ................................................64
Figure 5.8-1 Logic Diagram: Harmonic Block Feature (81HBL2) ..........................................................65
7SR21 & 7SR22 Argus Description of Operation
©2010 Siemens Protection Devices Limited Chapter 1 Page 5 of 71
List of Tables
Table 1-1
Ordering Information – 7SR21 Non-Directional Overcurrent..............................................7
Table 1-2 Ordering Information – 7SR22 Directional Overcurrent....................................................10
Table 2-1 Summary of Overcurrent Relay Configurations.................................................................14
Table 6-1 Operation Mode .................................................................................................................69
Symbols and Nomenclature
The following notational and formatting conventions are used within the remainder of this
document:
• Setting Menu Location MAIN MENU>SUB-MENU
• Setting: Elem name -Setting
• Setting value: value
• Alternatives: [1st] [2nd] [3rd]
7SR21 & 7SR22 Argus Description of Operation
©2010 Siemens Protection Devices Limited Chapter 1 Page 6 of 71
Section 1: Introduction
This manual is applicable to the following relays:
• 7SR21 Multi-Function Non-directional Overcurrent and Earth Fault Relay
• 7SR22 Multi-Function Directional Overcurrent and Directional Earth Fault Relay
The 7SR21 and 7SR22 relays integrate the protection and control elements required to provide a complete
overcurrent based protection.
The ‘Ordering Options’ Tables summarise the features available in each model.
General Safety Precautions
1 Current Transformer Circuits
The secondary circuit of a live CT must not be open circuited. Non-observance of this precaution can result in
injury to personnel or damage to equipment.
2 External Resistors
Where external resistors are fitted to the circuit, these may present a danger of electric shock or burns, if touched.
3 Fibre Optic Communication
Where fibre optic communication ports are fitted, the lasers are Class 1 devices but recommend they should not
be viewed directly. Optical power meters should be used to determine the operation or signal level of the device.
4 Front Cover
The front cover provides additional securing of the relay element within the case. The relay cover should be in
place during normal operating conditions.
!
!
!
!
7SR21 & 7SR22 Argus Description of Operation
©2010 Siemens Protection Devices Limited Chapter 1 Page 7 of 71
Table 1-1 Ordering Information – 7SR21 Non-Directional Overcurrent
Product description Variants Order No.
Nondirectional O/C Relay 7 S R 2 1 0 □ - 1 □ A □ □ -0□ A0
▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲
Multi function overcurrent || | | | | ||
and earth fault protection || | | | | ||
relay Protection Product || | | | | ||
Overcurrent – Non Directional 1 | | | | | ||
| | | | | ||
Case I/O and Fascia
1)
| | | | | ||
E6 case, 4 CT, 9 Binary Inputs / 8 Binary Outputs, 8 LEDs 2 | | | | | |
E8 case, 4 CT, 19 Binary Inputs / 16 Binary Outputs, 16LEDs 3 | | | | | |
E8 case, 4 CT, 19 Binary Inputs / 16 Binary Outputs, 8 LEDs + 6
Keys
4 |
|
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|
| | | | ||
Measuring Input | | | | ||
1/5 A, 50/60Hz 1 | | | | |
| | | | |
Auxiliary voltage | | | | |
30 to 220V DC, binary input threshold 19V DC A | | | |
30 to 220V DC, binary input threshold 88V DC B | | ||
| | | |
Communication Interface | | | |
Standard version – included in all models, USB front port, RS485 rear port 1 | ||
Standard version – plus additional rear F/O ST connectors (x2) and IRIG-B 2 | ||
Standard version – plus additional rear 1x RS485 and IRIG-B 3 | ||
Standard version – plus additional rear 1x RS232 and IRIG-B 4 | ||
| ||
Protocol | ||
IEC 60870-5-103 and Modbus RTU (user selectable setting) 1 ||
IEC 60870-5-103, Modbus RTU and DNP3.0 (user selectable setting) 2 ||
||
Protection Function Packages ||
Standard version – Included in all models
37 Undercurrent
46BC Broken conductor/load unbalance
46NPS Negative phase sequence overcurrent
49 Thermal overload
50 Instantaneous phase fault overcurrent
50BF Circuit breaker fail
50G/50N Instantaneous earth fault
51 Time delayed phase fault overcurrent
51G/51N Time delayed earth fault/SEF
60CTS-I CT Supervision
64H High Impedance REF
74TC Trip circuit supervision
81HBL2 2
nd
harmonic block/inrush restraint
Cold load pickup
Programmable logic
C
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Standard version – plus
79 Autoreclose
D |
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Additional Functionality |
No Additional Functionality A
7SR21 & 7SR22 Argus Description of Operation
©2010 Siemens Protection Devices Limited Chapter 1 Page 8 of 71
7SR21
I
L1
(I
A
)
I
L2
(I
B
)
I
L3
(I
C
)
I
4
(I
G
/I
SEF
)
37
(x2)
49
50
(x2)
51
(x2)
50G
(x2)
51G
(x2)
50
BF
50N
(x2)
51N
(x2)
46
BC
46
NPS
(x2)
81
HBL
2
37
(x2)
49
50
(x2)
50
BF
81
HBL
2
37
(x2)
49
50
(x2)
50
BF
81
HBL
2
74
TCS
51
(x2)
51
(x2)
64
REF
79
Optional
50
SEF
(x2)
51
SEF
(x2)
81
HBL
2N
60
CTS-
I
60
CTS-
I
60
CTS-
I
37G
(x2)
Figure 1-1 Functional Diagram of 7SR21 Relay
7SR21 & 7SR22 Argus Description of Operation
©2010 Siemens Protection Devices Limited Chapter 1 Page 9 of 71
BO 1
GND.
BI 1
+ve
-ve
+ve
-ve
I
L1
(I
A
)
3
1
22
24
28
2
4
BI 2
+ve
-ve
6
8
BI 3
+ve
-ve
10
12
I
L2
(I
B
)
I
L3
(I
C
)
I
4
(I
G
/I
SEF
)
13
14
15
16
BI 4
+ve
18
BI 5
+ve
20
BI 6
+ve
-ve
22
25
BI 7
+ve
24
BI 8
+ve
26
BI 9
+ve
-ve
28
27
BO 2
9
5
7
BO 3
15
11
13
BO 4
19
17
BO 5
23
21
BO 6
BO 7
19
17
BO 8
23
21
1A
5A
1
2
3
4
1A
5A
5
6
7
8
1A
5A
9
10
11
12
1A
5A
7SR21
BI 10
+ve
-ve
2
4
BI 11
+ve
-ve
6
8
BI 12
+ve
10
BO 9
3
1
BO 10
7
5
BO 11
11
9
BI 13
+ve
12
BI 14
+ve
14
BI 15
+ve
-ve
16
18
BI 16
20
BI 17
+ve
22
BI 18
+ve
24
BI 19
+ve
-ve
26
28
+ve
BO 12
15
13
21
19
17
BO 13
BO 14
27
25
23
BO 15
BO 16
A
Analogue
B
PSU
C
Optional
I/O
1 2
27 28
1 21 2
27 2827 28
Data
Comms
(Optional)
A
B
C
A
RS485
Screen
B
Term.
14
16
18
20
25
26
27
Rear View
Arrangement of terminals and modules
Shows contacts internal to relay case
assembly.
Contacts close when the relay chassis is
withdrawn from case
NOTES
BI = Binary Input
BO = Binary Output
Figure 1-2 Connections Diagram for 7SR21 Relay
7SR21 & 7SR22 Argus Description of Operation
©2010 Siemens Protection Devices Limited Chapter 1 Page 10 of 71
Table 1-2 Ordering Information – 7SR22 Directional Overcurrent
Product description Variants Order No.
Directional O/C Relay 7 S R 2 2 0 □ - 2 □ A □ □ - 0 □ A0
▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲
Multi function overcurrent || | | | | ||
and earth fault protection || | | | | ||
relay Protection Product || | | | | ||
Overcurrent – Directional 2 | | | | | ||
| | | | | ||
Case I/O and Fascia
1)
| | | | | ||
E6 case, 5 CT, 4 VT, 3 Binary Inputs / 6 Binary Outputs, 8 LEDs 2 | | | | C |
E8 case, 5 CT, 4 VT, 13 Binary Inputs / 14 Binary Outputs, 16
LEDs
3 |
|
|
|
|
|
|
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|
|
|
E8 case, 5 CT, 4 VT, 13 Binary Inputs / 14 Binary Outputs, 8
LEDs + 6 Keys
4 |
|
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| | | | ||
Measuring Input | | | | ||
1/5 A, 63.5/110V, 50/60Hz 2 | | | | |
| | | | |
Auxiliary voltage | | | | |
30 to 220V DC, binary input threshold 19V DC A | | | |
30 to 220V DC, binary input threshold 88V DC B | | ||
| | | |
Communication Interface | | | |
Standard version – included in all models, USB front port, RS485 rear port 1 | ||
Standard version – plus additional rear F/O ST connectors (x2) and IRIG-B 2 | ||
Standard version – plus additional rear 1x RS485 and IRIG-B 3 | ||
Standard version – plus additional rear 1x RS232 and IRIG-B 4 | ||
| ||
Protocol | ||
IEC 60870-5-103 and Modbus RTU (user selectable setting) 1 ||
IEC 60870-5-103, Modbus RTU and DNP3.0 (user selectable setting) 2 ||
Continued on next page ||
7SR21 & 7SR22 Argus Description of Operation
©2010 Siemens Protection Devices Limited Chapter 1 Page 11 of 71
Product description Variants Order No.
Directional O/C Relay 7 S R 2 2 0 □ -2 □ A □ □ - 0 □ A0
▲ ▲
Protection Function Packages | |
Standard version – Included in all models
27/59 Under/overvoltage
37 Undercurrent
37G Ground Undercurrent
37SEF SEF Undercurrent
46BC Broken conductor/load unbalance
46NPS Negative phase sequence overcurrent
47 Negative phase sequence voltage
49 Thermal overload
50BF Circuit breaker fail
51V Voltage controlled overcurrent
59N Neutral voltage displacement
60CTS CT supervision
60CTS-I CT Supervision
60VTS VT supervision
64H High Impedance REF
67/50 Directional instantaneous phase fault overcurrent
67/50G 67/50N Directional instantaneous earth fault
67/51 Directional time delayed phase fault overcurrent
67/51G 67/51N Directional time delayed earth fault/SEF
74TC Trip circuit supervision
81 Under/overfrenquency
81HBL2 2
nd
harmonic block/inrush restraint
Cold load pickup
Programmable logic
C
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Standard version – plus
79 Autoreclose
D |
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Additional Functionality |
No Additional Functionality A
7SR21 & 7SR22 Argus Description of Operation
©2010 Siemens Protection Devices Limited Chapter 1 Page 12 of 71
7SR22
46
BC
46
NPS
(x2)
37
(x2)
49
50
BF
V
L1
(V
A
)
V
L2
(V
B
)
V
L3
(V
C
)
V
4
(V
X
)
I
L1
(I
A
)
81
HBL
2
37
(x2)
49
50
BF
I
L2
(I
B
)
81
HBL
2
37
(x2)
49
50
BF
I
L3
(I
C
)
81
HBL
2
60
CTS
I
4
(I
G
)
I
5
(I
SEF
)
74
TCS
NOTE: The use of some
functions are mutually exclusive
67/
50
(x4)
67/
51
(x4)
67/
50N
(x4)
67/
50
(x4)
67/
50
(x4)
67/
51
(x4)
67/
51
(x4)
67/
51N
(x4)
67/
50G
(x4)
67/
51G
(x4)
67/
50S
(x4)
67/
51S
(x4)
64
H
27
59
27
59
(x4)
27
59
(x4)
27
59
(x4)
47
(x2)
81
(x6)
79
Optional
59N
(x2)
81
HBL
2N
60
VTS
51V
51V
51V
37G
(x2)
37S
(x2)
51c
60
CTS-
I
60
CTS-
I
60
CTS-
I
37
50
BF
37
50
BF
Figure 1-3 Functional Diagram of 7SR22 Relay
7SR21 & 7SR22 Argus Description of Operation
©2010 Siemens Protection Devices Limited Chapter 1 Page 13 of 71
7SR22
BO 1
GND.
BI 1
+ve
-ve
+ve
-ve
I
L1
(I
A
)
22
24
28
2
4
BI 2
+ve
-ve
6
8
BI 3
+ve
-ve
10
12
1
2
5
6
9
10
13
14
BO 2
BO 3
BO 4
BO 5
BO 6
A
17
18
19
20
V
L1
(V
A
)
21
22
V
L2
(V
B
)
23
24
V
L3
(V
C
)
25
26
V
4
(V
X
)
27
28
BI 4
+ve
-ve
2
4
BI 5
+ve
-ve
6
8
BI 6
+ve
10
BO 7
BO 8
BO 9
BI 7
+ve
12
BI 8
+ve
14
BI 9
+ve
-ve
16
18
BI 10
20
BI 11
+ve
22
BI 12
+ve
24
BI 13
+ve
-ve
26
28
+ve
BO 10
BO 11
BO 12
BO 13
BO 14
1A
5A
1A
5A
I
L2
(I
B
)
1A
5A
I
L3
(I
C
)
1A
5A
I
4
(I
G
)
15
16
11
12
1A
5A
I
5
(I
SEF
)
3
4
7
8
A
Analogue
B
PSU
C
Optional
I/O
1 2
27 28
1 21 2
27 2827 28
Data
Comms
(Optional)
Rear View
Arrangement of terminals and modules
B
C
A
Screen
B
Term.
14
16
18
20
Shows contacts internal to relay case
assembly.
Contacts close when the relay chassis is
withdrawn from case
NOTES
BI = Binary Input
BO = Binary Output
21
19
17
23
25
27
3
1
7
5
11
9
15
13
9
5
7
26
3
1
15
11
13
19
17
23
21
27
25
Figure 1-4 Connection Diagram for 7SR22 Relay
7SR21 & 7SR22 Argus Description of Operation
©2010 Siemens Protection Devices Limited Chapter 1 Page 14 of 71
Section 2: Hardware Description
2.1 General
The structure of the relay is based upon the Multi-function hardware platform. The relays are supplied in either
size E6 or size E8 cases (where 1 x E = width of 26mm). The hardware design provides commonality between
products and components across the Multi-function range of relays.
Table 2-1 Summary of Overcurrent Relay Configurations
Relay Current
Inputs
Voltage
Inputs
Binary
Inputs
Output
Relays
LEDs Function
Keys
Case
7SR2102 4 9 8 8 E6
7SR2103 4 19 16 16 E8
7SR2104 4 19 16 8 6 E8
7SR2202 5 4 3 6 8 E6
7SR2203 5 4 13 14 16 E8
7SR2204 5 4 13 14 8 6 E8
Relays are assembled from the following modules:
1. Front Fascia with three fixed function LEDs and ordering options of configurable LEDs/Function Keys.
2. Processor module
3. Analogue Input module, either
• 4 x Current + 6 x Binary Inputs + 2 x Binary Outputs (7SR21), or
• 5 x Current + 4 x Voltage (7SR22).
4. Power Supply and Basic Binary Input (BI) and Binary Output (BO).
5. Optional Binary Input/Output Module
• 10 x Binary Inputs + 8 x Binary Outputs
6. Optional Communications Module (2x rear fibre optic + 1x IRIG-B ports), (1x rear RS485 + 1x IRIG-B
port), (1x rear RS232 + 1x IRIG-B port)
2.2 Case
The relays are housed in cases designed to fit directly into standard panel racks. The two case options have
widths of 156mm (E6) and 208 mm (E8), both have a height of 177 mm (4U). The required panel depth (with
wiring clearance) is 242 mm. An additional 75 mm depth clearance should be allowed to accommodate the
bending radius of fibre optic data communications cables if fitted.
The complete relay assembly is withdrawable from the front of the case. Contacts in the case ensure that the CT
circuits remain short-circuited when the relay is removed.
The rear terminal blocks comprise M4 female terminals for wire connections. Each terminal can accept two 4mm
crimps.
Located at the top rear of the case is a screw clamp earthing point, this must be connected to the main panel
earth.
7SR21 & 7SR22 Argus Description of Operation
©2010 Siemens Protection Devices Limited Chapter 1 Page 15 of 71
2.3 Front Cover
With the transparent front cover in place the user only has access to the ▼ and TEST/RESET► buttons, via blue
push buttons, allowing all areas of the menu system to be viewed, but preventing setting changes and control
actions. The only ‘action’ that is permitted is to reset the Fault Data display, latched binary outputs and LEDs by
using the TEST/RESET button. The front cover is used to secure the relay assembly in the case.
2.4 Power Supply Unit (PSU)
The relay PSU can be directly connected to any substation dc system rated from 30V dc to 220V dc.
In the event of the station battery voltage level falling below the relay minimum operating level, the PSU will
automatically switch itself off and latch out – this prevents any PSU overload conditions occurring. The PSU is
reset by switching the auxiliary supply off and on.
2.5 Operator Interface/ Fascia
The operator interface is designed to provide a user-friendly method of controlling, entering settings and retrieving
data from the relay.
The warning and information labels on the relay fascia provide the following information:
Dielectric Test Voltage 2kV
Impulse Test Above 5kV
Caution: Risk of Electric Shock
Caution: Refer to Equipment Documentation
Figure 2.5 7SR21 with 3 + 8 LEDs in E6 Case
7SR21 & 7SR22 Argus Description of Operation
©2010 Siemens Protection Devices Limited Chapter 1 Page 16 of 71
Figure 2.5-1 7SR22 with 3 + 16 LEDs in E8 Case
Figure 2.5-2 7SR22 with Function Keys and 3 + 8 LEDs in E8 Case
NOTE: Pushbuttons on cover not shown
The fascia is an integral part of the relay. Handles are located at each side of the element to allow it to be
withdrawn from the relay case.
7SR21 & 7SR22 Argus Description of Operation
©2010 Siemens Protection Devices Limited Chapter 1 Page 17 of 71
Relay Information
Above the LCD three labels are provided, these provide the following information:
1) Product name and order code.
2) Nominal current rating, rated frequency, voltage rating, auxiliary dc supply rating, binary input supply
rating, configuration and serial number.
3) Blank label for user defined information.
A ‘template’ is available to allow users to create and print customised labels.
Liquid Crystal Display (LCD)
A 4 line by 20-character liquid crystal display indicates settings, instrumentation, fault data and control
commands.
To conserve power the display backlighting is extinguished when no buttons are pressed for a user defined
period. A setting within the “SYSTEM CONFIG” menu allows the timeout to be adjusted from 1 to 60 minutes and
“Off” (backlight permanently on). After an hour the display is completely de-activated. Pressing any key will re-
activate the display.
The LCD contrast can be adjusted using a flat blade screwdriver to turn the screw located below the contrast
symbol
. Turning the screw clockwise increases the contrast, anti-clockwise reduces the contrast.
User defined indentifying text can be programmed into the relay using the System config/Relay Identifier
setting. The ‘Relay Identifier’ text is displayed on the LCD display at the top level of the menu structure and is
used in communication with Reydisp to identify the relay. Pressing the Cancel button several times will always
return the user to this screen.
‘PROTECTION HEALTHY’ LED
This green LED is steadily illuminated to indicate that DC voltage has been applied to the relay power supply and
that the relay is operating correctly. If the internal relay watchdog detects an internal fault then this LED will
continuously flash.
‘PICKUP’ LED
This yellow LED is illuminated to indicate that a user selectable function(s) has picked up. The LED will self reset
after the initiating condition has been removed. The same LED can be assigned two different colours dependent
upon whether a Pickup or Operate condition exists.
Functions are assigned to the PICKUP LED in the OUTPUT CONFIG>PICKUP CONFIG menu.
‘TRIP’ LED
This red LED is steadily illuminated to indicate that a user selectable function has operated to trip the circuit
breaker. Functions are assigned to the ‘Trip’ LED using the OUTPUT CONFIG>Trip Contacts setting.
Operation of the LED is latched and can be reset by either pressing the TEST/RESET► button, energising a
suitably programmed binary input, or, by sending an appropriate command over the data communications
channel(s).
Indication LEDs
Relays have either 8 or 16 user programmable LED indicators. Each LED can be programmed to be illuminated
as either green, yellow or red. Where an LED is programmed to be lit both red and green it will illuminate yellow.
Functions are assigned to the LEDs in the OUTPUT CONFIG>OUTPUT MATRIX menu.
Each LED can be labelled by withdrawing the relay and inserting a label strip into the pocket behind the front
fascia. A ‘template’ is available to allow users to create and print customised legends.
Each LED can be user programmed as hand or self –resetting. Hand reset LEDs can be reset by either pressing
the TEST/RESET► button, energising a suitably programmed binary input, or, by sending an appropriate
command over the data communications channel(s).
7SR21 & 7SR22 Argus Description of Operation
©2010 Siemens Protection Devices Limited Chapter 1 Page 18 of 71
The status of hand reset LEDs is maintained by a back up storage capacitor in the event of an interruption to the
d.c. supply voltage.
Standard Pushbuttons
The relay is supplied as standard with five pushbuttons. The buttons are used to navigate the menu structure and
control relay functions. They are labelled:
▲ Increases a setting or moves up menu.
▼ Decreases a setting or moves down menu.
TEST/RESET► Moves right, can be used to reset selected functionality and for LED test (at
relay identifier screen).
ENTER Used to initiate and accept settings changes.
CANCEL. Used to cancel settings changes and/or move up the menu structure by one
level per press.
NOTE: All settings and configuration of LEDs, BI, BO and function keys can be accessed and set by the user
using these keys. Alternatively configuration/settings files can be loaded into the relay using ‘Reydisp Evolution’.
Function Keys/ LEDs (Optional)
Six additional programmable pushbuttons can be specified. These can be configured by the user to initiate
selected functions from the Control menu (INPUT CONFIG > FUNCTION KEY MATRIX).
Each pushbutton has an associated LED. LEDs can be programmed as hand or self reset and can be illuminated
as green, yellow or red (OUTPUT CONFIG > LED CONFIG).
Function keys can be used with Quick Logic.
2.6 Current Inputs
Four current inputs are provided in the 7SR21 relay and five inputs are provided in the 7SR22 relay
Current inputs are located on the Analogue Input module. Terminals are available for both 1A and 5A inputs.
Current is sampled at 1600Hz for both 50Hz and 60Hz system frequencies. Protection and monitoring functions of
the relay use either the Fundamental Frequency RMS or the True RMS value of current appropriate to the
individual function.
The waveform recorder samples and displays current input waveforms at 1600Hz.
NB: The Relay has a flat frequency response measuring harmonic currents up to and including the 50th Harmonic
but does not measure the content at the aliasing frequencies i.e. 800 Hz (16th harmonic) + 1600 Hz (32nd
harmonic) + 2400 Hz (48th harmonic).
2.7 Voltage Inputs
Four voltage inputs are provided in the 7SR22 relay.
Voltage inputs are located on the Analogue Input module.
Voltage is sampled at 1600Hz for both 50Hz and 60Hz system frequencies. Protection and monitoring functions of
the relay use fundamental frequency voltage measurement.
The waveform recorder samples and displays voltage input waveforms at 1600Hz.
7SR21 & 7SR22 Argus Description of Operation
©2010 Siemens Protection Devices Limited Chapter 1 Page 19 of 71
2.8 Binary Inputs
The binary inputs are operated from a suitably rated dc supply.
Relays are fitted with 3, 9, 13 or 19 binary inputs (BI). The user can assign any binary input to any of the available
functions (INPUT CONFIG > INPUT MATRIX).
The Power Supply module includes the relay basic I/O. The module includes 3 x BI and 6 x BO.
Non-directional (7SR21) relays have an additional 6 x BI on the analogue module.
Additional I/O modules may be fitted, these provide 10 x BI.
Pick-up (PU) and drop-off (DO) time delays are associated with each binary input. Where no pick-up time delay
has been applied the input may pick up due to induced ac voltage on the wiring connections (e.g. cross site
wiring). The default pick-up time of 20ms provides ac immunity. Each input can be programmed independently.
Each input may be logically inverted to facilitate integration of the relay within the user scheme. When inverted the
relay indicates that the BI is energised when no d.c. is applied. Inversion occurs before the PU & DO time delay,
see fig. 2.8-1.
Each input may be mapped to any front Fascia indication LED and/or to any Binary output contact and can also
be used with the internal user programmable logic. This allows the relay to provide panel indications and alarms.
Event
BI 1
Binary Input 1
=1
Inverted Inputs
BI 1 inverted
BI 1 P/U Delay
Event
BI n
Binary Input n
=1
BI n inverted
BI n P/U Delay
INPUT CONFIG>
INPUT MATRIX
(Or gates)
Logic signals,
e.g. '51-1 Inhibit'
BI 1 D/O Delay
BI n D/O Delay
INPUT
CONFIG>
BINARY
INPUT
CONFIG
Figure 2.8-1 Binary Input Logic
7SR21 & 7SR22 Argus Description of Operation
©2010 Siemens Protection Devices Limited Chapter 1 Page 20 of 71
2.9 Binary Outputs (Output Relays)
Relays are fitted with 6, 8, 14 or 16 binary outputs. All outputs are fully user configurable and can be programmed
to operate from any or all of the available functions.
The Power Supply module includes the relay basic I/O. The module includes six binary outputs each fitted with 1
contact – providing in total 1 x normally closed (NC), 2 x change-over (CO) and 3 x normally open (NO) contacts.
Non-directional (7SR21) relays have two additional binary outputs providing 2 x NO contacts on the analogue
module. Additional I/O modules may be fitted; these provide 8 x NO contacts.
In the default mode of operation binary outputs are self reset and remain energised for a user configurable
minimum time of up to 60 seconds. If required, outputs can be programmed to operate as ‘hand reset’ relays.
The binary outputs can be used to operate the trip coils of the circuit breaker directly where the trip coil current
does not exceed the 'make and carry' contact rating. The circuit breaker auxiliary contacts or other in-series
auxiliary device must be used to break the trip coil current.
When the relay is withdrawn from the case all normally closed contacts will be open circuited. This should be
considered in the design of the control and protection circuitry.
Notes on Hand Reset Outputs
Hand reset outputs can be reset by either pressing the TEST/RESET► button, by energising a suitably
programmed binary input, or, by sending an appropriate command over the data communications channel(s).
On loss of the auxiliary supply hand-reset outputs will reset. When the auxiliary supply is re-established the binary
output will remain in the reset state unless the initiating condition is still present.
Notes on Self Reset Outputs
Self reset operation has a minimum reset time of 100ms
With a failed breaker condition the relay may remain operated until current flow in the primary system is
interrupted by an upstream device. The relay will then reset and attempt to interrupt trip coil current flowing
through an output contact. Where this level is above the break rating of the output contact an auxiliary relay with
heavy-duty contacts should be utilised.
Figure 2.9-1 Binary Output Logic
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