Siemens Argus 7SR21 User manual

7SR21 & 7SR22 Argus Commissioning and Maintenance
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
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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
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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 Function diagrams amended, return form removed 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

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Contents
Document Release History....................................................................................................................1
Software Revision History.....................................................................................................................1
Contents..................................................................................................................................................2
Section 1: Common Functions .............................................................................................................5
1.1 Overview ...................................................................................................................................5
1.2 Before Testing...........................................................................................................................5
1.2.1 Safety ...........................................................................................................................5
1.2.2 Sequence of Tests .......................................................................................................5
1.2.3 Test Equipment ............................................................................................................6
1.2.4 Precautions ..................................................................................................................6
1.2.5 Applying Settings .........................................................................................................6
1.3 Tests .........................................................................................................................................8
1.3.1 Inspection .....................................................................................................................8
1.3.2 Secondary Injection Tests............................................................................................8
1.3.3 Primary Injection Tests.................................................................................................8
1.3.4 Putting into Service ......................................................................................................8
1.4 AC Energising Quantities..........................................................................................................9
1.5 Binary Inputs ...........................................................................................................................10
1.6 Binary Outputs ........................................................................................................................11
1.7 Relay Case Shorting Contacts................................................................................................12
Section 2: Protection Functions.........................................................................................................13
2.1 Phase Directional Polarity Check............................................................................................14
2.1.1 2 out of 3 logic............................................................................................................15
2.2 Phase Overcurrent (67/50,67/51) ...........................................................................................16
2.2.1 Definite Time Overcurrent (50) ...............................................................................17
2.2.2 Inverse Time Overcurrent (51) .................................................................................17
2.3 Voltage Controlled Overcurrent (51V) ....................................................................................19
2.4 Cold Load (51C)......................................................................................................................21
2.4.1 Inverse Time Overcurrent (51C) ..............................................................................22
2.5 Directional Earth Fault Polarity Check (67N) ..........................................................................24
2.6 Derived Earth Fault (67/50N, 67/51N) ....................................................................................25
2.6.1 Directional Polarity .....................................................................................................26
2.6.2 Definite Time Overcurrent (50N).............................................................................26
2.6.3 Inverse Time Overcurrent (51N) ..............................................................................26
2.7 Measured Earth fault (67/50G,67/51G) ..................................................................................29
2.7.1 Directional Polarity .....................................................................................................30
2.7.2 Definite Time Overcurrent (67/50G)........................................................................30
2.7.3 Inverse Time Overcurrent (67/51G) .........................................................................30
2.8 Sensitive Earth fault (67/50S,67/51S).....................................................................................33
2.8.1 Directional Polarity .....................................................................................................34
2.8.2 Definite Time Overcurrent (50SEF) ........................................................................34
2.8.3 Inverse Time Overcurrent (51SEF)..........................................................................34
2.9 Restricted Earth fault (64H) ..................................................................................................37
2.10 Negative Phase Sequence Overcurrent (46NPS) ..................................................................39
2.10.1 Definite Time NPS Overcurrent (46DT) ..................................................................40
2.10.2 Inverse Time NPS Overcurrent (46IT) .....................................................................40
2.11 Undercurrent (37)..................................................................................................................42

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2.12 Thermal Overload (49)............................................................................................................44
2.13 Over/Under Voltage ................................................................................................................46
2.13.1 Phase Under/Over Voltage (27/59)...........................................................................46
2.13.2 Undervoltage Guard (27/59UVG) ..............................................................................48
2.13.3 Vx Under/Over Voltage (Vx 27/59) ..........................................................................49
2.13.4 NPS Overvoltage (47) ................................................................................................51
2.13.5 Neutral Overvoltage (59N) .........................................................................................53
2.13.6 Definite Time (59NDT) ...............................................................................................53
2.13.7 Inverse Time (59NIT) .................................................................................................54
2.13.8 Under/Over Frequency (81) .......................................................................................55
Section 3: Supervision Functions ......................................................................................................57
3.1 CB Fail (50BF) .......................................................................................................................57
3.2 Voltage Transformer Supervision (60VTS)...........................................................................59
3.2.1 1 or 2 Phase VT fail....................................................................................................60
3.2.2 3 Phase VT fail...........................................................................................................60
3.3 Current Transformer Supervision (60CTS)...........................................................................61
3.4 Broken Conductor (46BC).....................................................................................................63
3.5 Trip Circuit Supervision (74TCS) ..........................................................................................65
3.6 Magnetising Inrush Detector (81HBL) ..................................................................................66
Section 4: Control & Logic Functions................................................................................................67
4.1 Autoreclose (79)......................................................................................................................67
4.2 Quick Logic .............................................................................................................................67
Section 5: Testing and Maintenance..................................................................................................68
5.1 Periodic Tests .........................................................................................................................68
5.2 Maintenance............................................................................................................................68
5.3 Troubleshooting ......................................................................................................................68

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List of Figures
Figure 2-1 Directional Phase Fault Boundary System Angles ............................................................15
Figure 2-2 Phase Overcurrent.............................................................................................................16
Figure 2-3 Voltage Controlled Overcurrent .........................................................................................19
Figure 2-4 Cold Load...........................................................................................................................21
Figure 2-5 Cold Load Logic diagram...................................................................................................22
Figure 2-6 Directional Earth Fault Boundary System Angles..............................................................24
Figure 2-7 Derived Earth Fault............................................................................................................25
Figure 2-8 Measured Earth Fault ........................................................................................................29
Figure 2-9 Sensitive Earth Fault..........................................................................................................33
Figure 2-10 Restricted Earth Fault ........................................................................................................37
Figure 2-11 Negative Phase Sequence Overcurrent ............................................................................39
Figure 2-12 Undercurrent ......................................................................................................................42
Figure 2-13 Thermal Overload ..............................................................................................................44
Figure 2-14 Phase Under/Over Voltage................................................................................................46
Figure 2-15 Vx Under/Over Voltage......................................................................................................49
Figure 2-16 NPS Overvoltage ...............................................................................................................51
Figure 2-17 Neutral Overvoltage...........................................................................................................53
Figure 2-18 Under/Over Frequency ......................................................................................................55
Figure 3-1 CB Fail ...............................................................................................................................57
Figure 3-2 Voltage Transformer Supervision ......................................................................................59
Figure 3-3 Current Transformer Supervision ......................................................................................61
Figure 3-4 Broken Conductor..............................................................................................................63
Figure 3-5 Trip Circuit Supervision......................................................................................................65
Figure 3-6 Magnetising Inrush Detector..............................................................................................66

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Section 1: Common Functions
1.1 Overview
Commissioning tests are carried out to prove:
a) Equipment has not been damaged in transit.
b) Equipment has been correctly connected and installed.
c) Prove characteristics of the protection and settings which are based on calculations.
d) Confirm that settings have been correctly applied.
e) To obtain a set of test results for future reference.
1.2 Before Testing
1.2.1 Safety
The commissioning and maintenance of this equipment should only be carried out by skilled personnel trained in
protective relay maintenance and capable of observing all the safety precautions and regulations appropriate to
this type of equipment and also the associated primary plant.
Ensure that all test equipment and leads have been correctly maintained and are in good condition. It is
recommended that all power supplies to test equipment be connected via a Residual Current Device (RCD),
which should be located as close to the supply source as possible.
The choice of test instrument and test leads must be appropriate to the application. Fused instrument leads
should be used when measurements of power sources are involved, since the selection of an inappropriate range
on a multi-range instrument could lead to a dangerous flashover. Fused test leads should not be used where the
measurement of a current transformer (C.T.) secondary current is involved, the failure or blowing of an instrument
fuse or the operation of an instrument cut-out could cause the secondary winding of the C.T. to become an open
circuit.
Open circuit secondary windings on energised current transformers are a hazard that can produce high voltages
dangerous to personnel and damaging to equipment, test procedures must be devised so as to eliminate this risk.
1.2.2 Sequence of Tests
If other equipment is to be tested at the same time, then such testing must be co-ordinated to avoid danger to
personnel and equipment.
When cabling and wiring is complete, a comprehensive check of all terminations for tightness and compliance
with the approved diagrams must be carried out. This can then be followed by the insulation resistance tests,
which if satisfactory allows the wiring to be energised by either the appropriate supply or test supplies.
When primary injection tests are completed satisfactorily, all remaining systems can be functionally tested before
the primary circuit is energised. Some circuits may require further tests before being put on load.
Protection relay testing will require access to the protection system wiring diagrams, relay configuration
information and protection settings. The following sequence of tests is loosely based on the arrangement of the
relay menu structure. A test log based on the actual tests completed should be recorded for each relay tested.
The ‘Description of Operation’ section of this manual provides detailed information regarding the operation of
each function of the relay.

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1.2.3 Test Equipment
Required test equipment is: -
1. Secondary injection equipment with integral time interval meter
2. Primary injection equipment
3. A d.c. supply with nominal voltage within the working range of the relay's d.c. auxiliary supply rating
4. A d.c. supply with nominal voltage within the working range of the relay’s d.c. binary input rating
5. Other equipment as appropriate to the protection being commissioned – this will be specified in the
product specific documentation.
The secondary injection equipment should be appropriate to the protection functions to be tested. Additional
equipment for general tests and for testing the communications channel is:
Portable PC with appropriate interface equipment: -
6. Portable PC with appropriate interface equipment.
7. Printer to operate from the above PC (Optional).
Use of PC to facilitate testing
The functions of Reydisp Evolution (see Section 2: Settings and Instruments) can be used during the
commissioning tests to assist with test procedures or to provide documentation recording the test and test
parameters. One method is to clear both the waveform and event records before each test is started, then, after
the test upload from the relay the settings, events and waveform files generated as a result of application of the
test. These can then be saved off to retain a comprehensive record of that test.
Relay settings files can be prepared on the PC (offline) or on the relay before testing commences. These settings
should be saved for reference and compared with the settings at the end of testing to check that errors have not
been introduced during testing and that any temporary changes to settings to suit the test process are returned to
the required service state.
A copy of the Relay Settings as a Rich Text Format (.rtf) file suitable for printing or for record purposes can be
produced from Reydisp as follows. From the File menu select Save As, change the file type to Export
Default/Actual Setting (.RTF) and input a suitable filename.
When testing is completed the event and waveform records should be cleared and the settings file checked to
ensure that the required in-service settings are being applied.
1.2.4 Precautions
Before electrical testing commences the equipment should be isolated from the current and voltage transformers.
The current transformers should be short-circuited in line with the local site procedure. The tripping and alarm
circuits should also be isolated where practical. The provision and use of secondary injection test sockets on the
panel simplifies the isolation and test procedure.
Ensure that the correct auxiliary supply voltage and polarity is applied. See the relevant scheme diagrams for the
relay connections.
Check that the nominal secondary current rating of the current and voltage transformers has been correctly set in
the System Config. menu of the relay.
1.2.5 Applying Settings
The relay settings for the particular application should be applied before any secondary testing occurs. If they are
not available then the relay has default settings that can be used for pre-commissioning tests.
Note that the tripping and alarm contacts for any function must be programmed correctly before any scheme tests
are carried out.
Relays feature multiple settings groups, only one of which is active at a time. In applications where more than one
settings group is to be used it may be necessary to test the relay in more than one configuration.
Note. One group may be used as a ‘Test’ group to hold test-only settings that can be used for regular
maintenance testing, eliminating the need for the Test Engineer to interfere with the actual in-service settings in
the normally active group. This Test group may also be used for functional testing where it is necessary to disable
or change settings to facilitate testing.
When using settings groups it is important to remember that the relay need not necessarily be operating
according to the settings that are currently being displayed.

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There is an ‘active settings group’ on which the relay operates and an ‘edit/view settings group’ which is visible on
the display and which can be altered. This allows the settings in one group to be altered from the relay fascia
while the protection continues to operate on a different unaffected group. The ‘Active Settings Group’ and the ‘Edit
Settings Group’ are selected in the ‘System Configuration Menu’.
The currently Active Group and the group currently Viewed are shown at the top of the display in the Settings
display screen. If the View Group is not shown at the top of the display, this indicates that the setting is common
to all groups. CT/VT ratio, I/O mapping and other settings which are directly related to hardware are common to
all groups.
If the relay is allowed to trip during testing then the instruments display will be interrupted and replaced by the
‘Trip Alert’ screen which displays fault data information. If this normal operation interferes with testing then this
function can be temporarily disabled for the duration of testing by use of the Trip Alert Enabled/Disabled setting in
the System Config Menu.
After applying a settings change to the relay, which may involve a change to the indication and output contacts,
the TEST/RESET key should be pressed to ensure any existing indication and output is correctly cleared.

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1.3 Tests
1.3.1 Inspection
Ensure that all connections are tight and correct to the relay wiring diagram and the scheme diagram. Record any
deviations. Check that the relay is correctly programmed and that it is fully inserted into the case. Refer to
‘Section 2: Settings and Instruments’ for information on programming the relay.
1.3.2 Secondary Injection Tests
Select the required relay configuration and settings for the application.
Isolate the auxiliary D.C. supplies for alarm and tripping from the relay and remove the trip and intertrip links.
Carry out injection tests for each relay function, as described in this document
For all high current tests it must be ensured that the test equipment has the required rating and stability and that
the relay is not stressed beyond its thermal limit.
1.3.3 Primary Injection Tests
Primary injection tests are essential to check the ratio and polarity of the transformers as well as the secondary
wiring.
Note. If the current transformers associated with the protection are located in power transformer bushings it may
not be possible to apply test connections between the current transformer and the power transformer windings.
Primary injection is needed, however, to verify the polarity of the CTs. In these circumstances primary current
must be injected through the associated power transformer winding. It may be necessary to short circuit another
winding in order to allow current to flow. During these primary injection tests the injected current is likely to be
small due to the impedance of the transformer.
1.3.4 Putting into Service
After tests have been performed satisfactorily the relay should be put back into service as follows:-
Remove all test connections.
Replace all secondary circuit fuses and links, or close m.c.b.
Ensure the Protection Healthy LED is on, steady, and that all LED indications are correct. If necessary press
CANCEL until the Relay Identifier screen is displayed, then press TEST/RESET to reset the indication LEDs.
The relay meters should be checked in Instruments Mode with the relay on load
The relay settings should be downloaded to a computer and a printout of the settings produced. The installed
settings should then be compared against the required settings supplied before testing began. Automated setting
comparison can be carried out by Reydisp using the Compare Settings Groups function in the Edit menu. Any
modified settings will be clearly highlighted.

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1.4 AC Energising Quantities
Voltage and current measurement for each input channel is displayed in the Instrumentation Mode sub-menus,
each input should be checked for correct connection and measurement accuracy by single phase secondary
injection at nominal levels. Ensure that the correct instrument displays the applied signal within limits of the
Performance Specification.
Applied Current Applied Voltage
I
A IBI CI GI SEF V A/VAB VB/VBC VC/VCB VX
Secondary
Primary
Apply 3P balanced Current and Voltage at nominal levels and ensure that the measured Zero Phase Sequence
and Negative Phase Sequence quantities are approximately zero.
ZPS NPS
Voltage
Current

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1.5 Binary Inputs
The operation of the binary input(s) can be monitored on the ‘Binary Input Meters’ display shown in ‘Instruments
Mode’. Apply the required supply voltage onto each binary input in turn and check for correct operation.
Depending on the application, each binary input may be programmed to perform a specific function; each binary
should be checked to prove that its mapping and functionality is as set as part of the Scheme Operation tests.
Where the pick-up timers associated with a binary input are set these delays should be checked either as part of
the scheme logic or individually. To check a binary pick-up time delay, temporarily map the binary to an output
relay that has a normally open contact. This can be achieved in the Output Matrix sub-menu by utilising the BI n
Operated settings. Use an external timer to measure the interval between binary energisation and closure of the
output contacts. Similarly, to measure the drop-off delay, map to an output relay that has a normally closed
contact, time the interval between binary de-energisation and closure of the output contacts.
Note. The time measured will include an additional delay, typically less than 20ms, due to the response time of
the binary input hardware, software processing time and the operate time of the output relay.
BI Tested DO
Delay Measured PU Delay Measured Notes (method of initiation)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19

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1.6 Binary Outputs
A minimum of six output relays are provided. Two of these have change over contacts, BO2 & BO3, one has a
normally closed contact, BO1 and the remainder have normally open contacts.
Care should be observed with regard to connected devices when forcing contacts to operate for test purposes.
Short duration energisation can cause contact failure due to exceeding the break capacity when connected to
inductive load such as electrically reset trip relays.
Close each output relay in turn from the Reydisp Evolution PC programme, Relay – Control - Close output relay.
This function will energise the output for its minimum operate time. This time is specified in the Output Config -
Binary Output Config menu for each output relay and may be too short to measure with a continuity tester.
An alternative method of energising an output permanently so that wiring can be checked is to temporarily map
the relay being tested to the ‘Protection Healthy’ signal in the Output Matrix, as this signal is permanently
energised the mapped relay will be held energised, normally open contacts will be closed and vice versa.
BO Checked Notes (method of test)
1NC
2NO
2NC
3NO
3NC
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19

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1.7 Relay Case Shorting Contacts
CT inputs and terminals B25-B26 (Relay Withdrawn Alarm) are fitted with case mounted shorting contacts which
provide a closed contact when the relay is withdrawn from the case. The operation of these contacts should be
checked.
CT Shorting contacts checked
Relay Withdrawn Alarm Checked

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Section 2: Protection Functions
This section details the procedures for testing each protection function of the 7SR21 & 7SR22 relays. These tests
are carried out to verify the accuracy of the protection pick-ups and time delays at setting and to confirm correct
operation of any associated input and output functionality.
The exact model type must be checked to confirm the functions available in each type.
Guidance for calculating test input quantities is given in the relevant test description where required. In many
cases it may be necessary to disable some functions during the testing of other functions, this prevents any
ambiguity caused by the operation of multiple functions from one set of input quantities. The ‘Function Config’
Menu provides a convenient high level point at which all elements of a particular function can be
Enabled/Disabled to suit testing. The ‘Config’ tab in ‘Reydisp Evolution’ can be used to ‘Enable/Disable’ individual
elements. Note that this screen disables functions by applying setting changes to the relay and that any changes
must be sent to the relay to take effect and settings must be returned to their correct value after testing.
The table below indicates functions where function conflicts may occur during testing, consideration should be
given to disabling functions to avoid interference.
Any LED can be assigned to be a General Pickup LED in the Output Matrix menu and can be used to assess
operation of functions during testing if other functions are disabled or if the setting allocating General Pickup is
temporarily modified.
Voltage inputs may not be required for testing of non-directional Overcurrent elements but it may be
advantageous to apply balanced 3 phase nominal rated voltage to the VT inputs during testing to avoid
inadvertent operation of other functions. Particular care should be taken when testing overcurrent functions that
the thermal rating of the current inputs is not exceeded.
Function
Under Test
Phase
Overcurrent
Voltage Cont O/C
Cold Load
Derived E/F
Measured E/F
Sensitive E/F
Restricted E/F
NPS Overcurrent
Undercurrent
Thermal
Phase U/O voltage
NPS Overvoltage
U/O Frequency
CB Fail
VT Supervision
CT supervision
Broken Conductor
Trip cct
Supervision
Inrush Detector
Phase O O O O O O O
Voltage Cont O O O O O O O
Cold Load O O O O O O O
Derived E/F O O O O O O O
Measured E/F O
OOO
Sensitive E/F O
Restricted E/F O
NPS Overcurrent O O O O O O O
Undercurrent O O O
Thermal O O O O
Phase U/O O O O
NPS O
O O
U/O Frequency O O
CB Fail O O O O O O O O
VT Supervision OO
CT supervision O O
Broken O O O
O
Trip cct
Inrush Detector

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It should be considered that where several overlapping elements are used simultaneously, the overall protection
operate time may be dependent on the operation of different individual elements at the various levels of applied
current or voltage. The resulting composite characteristic may be tested by enabling all of the relevant applicable
elements or the element operations can be separated or disabled and tested individually.
All relay settings should be checked before testing begins. It is recommended that the relay settings are extracted
from the relay using Reydisp Evolution software and a copy of these settings is stored for reference during and
after testing. It may be necessary to disable some protection functions during the testing of other functions to
allow unambiguous results to be obtained.
Care must be taken to reset or re-enable any settings that have been temporarily altered during the testing before
the relay can be put into service. At the end of testing the relay settings should be compared to the file extracted
at the start to ensure that errors have not been introduced.
2.1 Phase Directional Polarity Check
If the relay has Directional Overcurrent elements, the common direction polarising can be checked independently
from the individual overcurrent elements and their settings.
In the INSTRUMENTS MODE display, indication is provided in the DIRECTIONAL METERS menu which displays
current direction under P/F Dir as forward or reverse based on the output states of the directional elements, i.e.
whether they see forward current, reverse current or neither for each pole with respect to the 67 Char Angle
setting in the Phase Overcurrent menu. This display and the equivalent Measured and Calculated Earth Fault
direction meters can be used as an aid to commissioning testing.
Check the direction of each pole in turn by connecting to the appropriate terminals. The table below shows
the polarising quantity for each pole.
Connections for Directional Polarity
Overcurrent pole Polarising voltage
Phase A VBC
Phase B VCA
Phase C VAB
2. Inject single phase rated current and apply single phase-phase rated voltage at the Char Angle (MTA) phase
angle setting, to each phase in turn. For each pole, monitor the directional display in the instrument menu
and check that indication of forward current (FWD) is displayed. To achieve the required forward
Characteristic Angle, the phase angle of the current should be greater than that of the polarising voltage by
the angle setting.
3. Repeat all of the above with the current connections reversed. Indication should now be given of reverse
(REV) current flow.
Phase A B C
Forward FWD FWD FWD
Reverse REV REV REV
Apply balanced 3 phase rated voltage and current with Vbc voltage as a 0deg reference and Ia at the
characteristic angle. Increase current phase angle until the ‘Fwd’ indication is extinguished. Record this angle
in the table below (Forward lead DO). Continue to increase/decrease the angle until the instrument reads
‘Rev’. Record the angle (Reverse lead PU). Reduce the current angle until the ’Rev’ extinguishes (Reverse
lead DO). and the ‘Fwd’ subsequently returns (Forward lead PU), recording the angles. Repeat the above
tests, starting from the Characteristic Angle, but reducing the current phase angle to record the directional
boundaries in the opposite (lag) direction. The recorded angle should be the angle at which the phase current
leads the phase-phase polarising voltage. This measurement is greatly simplified if the polarising reference
voltage is set to 0deg and the current phase angle is measured with respect to this reference.
Alternatively, the instrument can be checked at the 4 points marked a,b,c & d on Figure 2-1 only.

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VCVB
VA
IA
With balanced 3-phase system quantities:
Adjust the phase angle of the currents
relative to the voltages:
Verify directional pick-up and drop off at
points A, B, C and D
Alternatively,
Verify correct directional indication at points
a, b, c and d (C.A +750, +950, -750, -950)
A
B
D
C
a
d
b
c
FWD
REV
+600
+300
00
+2700
+1800
+2100
+2400
+900
VBC
Forward Reverse
Lag (point C) Lead (point A) Lead(point B) Lag (point D)
Pick-up Drop-off Pick-up Drop-off Pick-up Drop-off Pick-up Drop-off
MTA MTA-85
MTA+85 MTA-85 MTA-85
Phase A
Phase B
Phase C
Figure 2-1 Directional Phase Fault Boundary System Angles
4. With the instrument reading ‘Fwd’ or ‘Rev’, reduce the voltage until the element resets. Record the
minimum phase-phase operate voltage.
Minimum Voltage Setting Measured
2.1.1 2 out of 3 logic
Ensure that at least 1 Phase Overcurrent element is set to Directional. Apply balanced nominal voltage. Apply
current at a level above on phase A only at the characteristic angle for forward operation, normally 45º lagging.
Ensure no Directional Phase Overcurrent element operation occurs. Note that non-directional Phase Overcurrent
and Non-direction Earth Fault elements may operate unless disabled.
Repeat the test with Phase A current as above but also with equal current in the B phase at 180º to that in the A
phase.
1 phase current 2 phase current
No 50/51-n Operation 50/51-n operation

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2.2 Phase Overcurrent (67/50,67/51)
Figure 2-2 Phase Overcurrent
Voltage Inputs: VL1 (VA), VL2 (VB), VL3 (VC) for directional elements.
Current Inputs: IL1 (IA), IL2 (IB), IL3 (IC),
Disable: 51V, 51C, 46, 49, 50CBF, 79
Map Pickup LED: 51-n/50-n - Self Reset
Other protection functions may overlap with these functions during testing, it may be useful to disable some
functions to avoid ambiguity. It should be particularly noted that if the function is enabled, the 51C Cold Load
settings may modify the normal 50-n and 51-n settings if the CB is open during testing.
Voltage inputs may not be required for this function if the Phase Overcurrent functions are not directional but it
may be advantageous to apply balanced 3 phase nominal rated voltage to the VT inputs during testing to avoid
inadvertent operation of other functions. Particular care should be taken when testing overcurrent functions that
the thermal rating of the current inputs is not exceeded.

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2.2.1 Definite Time Overcurrent (50)
If DTL setting is small, gradually increase current until element operates.
If DTL is large apply 0.9x setting, check for no operation, apply 1.1x setting, and check operation
Apply 2x setting current if possible and record operating time
Phase Dir. Is
(Amps) DTL (sec) P.U. Current Amps Tol Operate Time
2 x Is Tol
IL1(IA)
IL2(IB)
IL3(IC)
Check correct indication, trip output, alarm contacts, waveform record.
2.2.2 Inverse Time Overcurrent (51)
It will be advantageous to map the function being tested to temporarily drive the relevant Pickup output in the
Pickup Config sub-menu in the Output Config menu as this will allow the Pick-up led to operate for the function.
Gradually increase current until Pickup LED operates.
Apply 2x setting current and record operating time,
Apply 5x setting current and record operating time.
Compare to calculated values for operating times
Gradually reduce current until the element drops off and record the level.
Operate Current Operate Time
Ph. Dir Char.
Curve Is (A) TM P.U.
(Amps) D.O. (Amps) Tol 2 x Is
(sec) 5 x Is (sec) Tol
IL1(IA)
IL2(IB)
P.U.
D.O.
&
TIMING
TESTS IL3(IC)
Calculated Timing values in seconds for TM =1.0
Curve 2 xIs 5 xIs
IEC-NI 10.03 4.28
IEC-VI 13.50 3.38
IEC-EI 26.67 3.33
IEC-LTI 120.00 30.00
ANSI-MI 3.80 1.69
ANSI-VI 7.03 1.31
ANSI-EI 9.52 1.30
Note that the operate time may be subject to the Minimum op time setting for the element and/or may have a
Follower DTL applied.

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2.2.2.1 Element Blocking
The Phase Overcurrent elements can be blocked by Binary Input Inhibit, VT Supervision and Inrush Detector
operation, as well as 79 Autoreclose settings for Inst/Delayed. The Characteristic can be modified by Cold Load
(51-n only) and Voltage Controlled Overcurrent and can be made non-directional by VT Supervision. This
functionality should be checked.
Element BI Inhibits VTS action Inrush Detector 79 Autoreclose
51-1
51-2
51-3
51-4
50-1
50-2
50-3
50-4
2.2.2.2 ANSI Reset
If the element is configured as an ANSI characteristic, it may have an ANSI (decaying) reset delay applied. If
ANSI reset is selected for an IEC characteristic element, the reset will be instantaneous.
ANSI reset times from operated condition to fully reset are as follows for zero applied current and Time multiplier
(TM) = 1.0. The reset curve characteristic type and TM is defined by the operating characteristic.
Curve Fully operated to reset with Zero current applied & TM=1 (secs)
ANSI-MI 4.85
ANSI-VI 21.6
ANSI-EI 29.1
Apply current in the following sequence, a) 2x setting for a time to ensure element operation, b) Zero current for
the reset time above (xTM), c) 2x setting for a time to ensure element operation. Check that the second operation
(c) is similar to the first (a) and in line with the expected operate time for the element at this current level.
Repeat the test with the reset time (b) reduced to 50% of the previous value. Ensure that the second operate time
(c) is 50% of the first (a) operate time.
Check correct indication, trip output, alarm contacts, waveform record.
Operate time
(expected) Reset time (calculated) Operate time (measured) 50% Reset Time
(calculated)
50% operate
time
(calculated)
50% operate
time
(measured)
First test (c) Second Test (c)

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2.3 Voltage Controlled Overcurrent (51V)
Figure 2-3 Voltage Controlled Overcurrent
Voltage Inputs: VL1 (VA), VL2 (VB), VL3 (VC)
Current Inputs: IL1 (IA), IL2 (IB), IL3 (IC),
Disable: 51C, 46, 37, 49, 50CBF, 79
Map Pickup LED: 51-n/50-n - Self Reset
Shaped Phase Overcurrent elements 51-n should be tested for pick-up and timing before this function is tested.
The General Pickup LED can be used to assess operation of this function if other functions are disabled or if the
setting allocating General Pickup is temporarily modified.
Apply nominal 3 phase balanced voltage. Apply 3 phase balanced current at a level below the normal 51-n setting
but above the effective 51V-n setting. Ensure that the thermal rating of the relay is not exceeded. Gradually
reduce the voltage until the a-b voltage is less than the Voltage setting. Pickup LED operation can be used to
confirm the Voltage setting. If the 51V-n current setting is above the continuous rating of the relay an alternative
procedure should be used, apply test current in short duration shots with applied voltage being gradually reduced
for each subsequent shot
Apply nominal 3 phase balanced voltage. Reduce the voltage such that the a-b voltage is 110% of the Voltage
setting
OC Phase Control Voltage
IL1(IA) V12(VAB)
IL2(IB) V23(VBC)
IL3(IC) V31(VCA)

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Gradually increase the a-b phase current or balanced 3P current until Pickup LED operates. Confirm result of
Phase O/C test above.
Reduce the applied voltage to a level such that V12(VAB) phase-phase voltage is less than 90% of the setting.
Gradually increase the I12(IAB) phase-phase current until Pickup LED operates.
Note that these elements may be set as directional. If this is the case, the phase angle of the current must be set
with respect to the voltage to produce operation of the elements.
Voltage Setting (V, p-p) Measured (V, p-p)
I Setting Multiplier Calculated PU Measured Tolerance
51-1 Pickup
51-2 Pickup
51-3 Pickup
51-4 Pickup
2.3.1.1 Element Blocking
The Voltage Controlled Overcurrent function can be set to Inhibit for VT Supervision operation. This functionality
should be checked. Apply balanced voltage and current. Reduce a-phase voltage to cause a VTS condition.
Increase 3P current until the element operates at its full setting, i.e. 51V settings are not used.
Element VTS action
51-1
51-2
51-3
51-4
Check correct indication, trip output, alarm contacts.