Completing The Test - Hitachi RET670 Commissioning Manual

1MRK 504 165-UEN Rev. K
7. Manually execute Raise commands to step up the tap changer one step for all transformers in
the parallel group
8. Check that the value of BUSVOLT is below overvoltage blocking level OVPartBK and above the
undervoltage blocking level UVPartBK.
9. Set the control mode to Auto for each transformer in the parallel control group
The Master in the parallel group will issue a Lower command after time delay t1, which will also
be repeated by the Follower transformers in the group.
10. Set Transformer 2 to Master of the parallel group and T1 to Follower (in that order) and repeat
steps 7 to 10. Undertake this same test by setting each Transformer in turn to Master
11. Note that voltage regulation will be mutually blocked if no transformer is set to Master in the
parallel group. To confirm this function, set T1 as Master and the other transformers in the
parallel grouper set as Follower. Without allocating a new Master, set T1 to Follower and note
the Automatic block state on the local HMI for all parallel transformers
12. Restore T1 to Master of the parallel transformer group and ensure that control mode for each
transformer is Automatic.
12.1.5

Completing the test

After the test is completed and relevant disturbance records are saved to document the test, go to
Main menu /Clear on the local HMI and clear all LEDs, the process eventlist and disturbances from
the IED.
Transformer protection RET670
Commissioning manual
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IEC13000252-1-en.vsd
Section 12
Primary injection testing
SEMOD176327-287 v3
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