Tests; Inspection; Secondary Injection Tests; Primary Injection Tests - Siemens 7SR18 Solkor Manual

7SR18 Commissioning & Maintenance Guide
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. 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.
1.2.7
T
ESTS
1.2.8
I
NSPECTION
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 the
Settings Guide and Instrumentation Guide sections of the technical manual for information on programming the
relay.
1.2.9
S
ECONDARY
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 inter-trip 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.
1.2.10
P I
RIMARY NJECTION
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.
1.2.11
P
UTTING INTO
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 Evolution using the Compare Settings Groups function in the Edit
menu. Any modified settings will be clearly highlighted.
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I T
NJECTION ESTS
T
ESTS
S
ERVICE
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