NOTE
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. The maximum duration of the current injection
should be limited in case an error is present such that the expected relay operation does not stop the test.
Primary Injection Tests
Primary tests may be done only by qualified personnel who are familiar with the commissioning of protection
systems, with the operation of the system, and with safety regulations and provisions (switching, earthing,
etc.).
Primary injection tests are essential to check the ratio and polarity of the transformers as well as the secondary
wiring.
Switching operations also have to be performed for complete commissioning of the protection system.
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 and limitations of test equip-
ment.
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 miniature circuit‑breakers.
•
Ensure the Protection Healthy LED is on and steady if configured, and that all LED indications are
correct. If necessary press the X key until the Relay Identifier screen is displayed, then press ▶ 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 copy stored for record 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 check operation of
Reydisp Manager. Settings can be downloaded from the device, and compared, using Reydisp Manager.
The described tests are for guidance for experienced personnel that can ensure that these are performed
safely.
Routine Maintenance
The device does not require scheduled preventative maintenance although some users apply periodic
checking schedules to all protection devices. Operational checking can be limited to periodic visual checks of
measured analogue values at the device instruments or the data provided over the communications channels
to supplement the continuous self-checking features of the device.
Repair
The device is designed with no user serviceable parts and if a device reports a failure it can be returned to
Siemens for investigation and repair. Contact and return details will be provided by the local Siemens office.
Necessary precautions such as isolating the equipment, power supply and connections should be applied
before investigating further, particularly with respect to safety earthing.
Functional Tests
9.1 General Notes
Reyrolle 7SR5, Overcurrent Protection Device, Device Manual 453
C53000-G7040-C014-1, Edition 11.2019
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