Bay Out Of Service For Maintenance - Hitachi Relion 670 Series Applications Manual

1MRK511407-UUS Rev. N
SMAI function delivers a magnitude of zero with good quality for all the channels. Thus, this has no effect
on a busbar protection, nor protections in an 1 1/2 circuit breaker configuration.
GUID-F723C815-3A26-481A-B046-21D1243E7080 V1 EN-US
Figure 116:
Procedure to bring protections back into service and enable maintenance of
a faulty merging unit
1. Disconnect bay
2. Energize binary input, block of bay. Protections are now back in service.
3. Maintenance of the merging unit can start.
Procedure to bring bay back into service after maintenance of a merging unit
1. Energize merging unit.
2. De-energize binary input block of bay. Protections are now back in service.
3. Reconnect bay.
19.3.3

Bay out of service for maintenance

When a bay need maintenance and has energized merging unit connected, it is always a risk to get
unplanned interruptions in the auxiliary power supply which may lead to unwanted blocking of
protections.
This is resolved by setting the merging unit "out of service" by setting the parameter "Operation" in "Main
menu/Configuration/Analog modules/Mu....", to "Out of service" instead of "In service". The merging unit
will look like it is in normal operation from the protection point of view, with perfect 0-value input values,
comparable to a TRM that is not connected. A hint will be shown to inform that a merging unit is out of
service.
Phasor measurement unit RES670
Application manual
SMAI function blocks exist in different cycle times, and all the SMAI blocks that receive SV
streams from the merging units must have the block input signal configured in the same way
to get the correct behavior.
Configuration of current inputs using SMAIs in a 1 1/2 circuit breaker application.
© 2017 - 2023 Hitachi Energy. All rights reserved
Section 19
Station communication
GUID-4E073C5A-F0E3-4FCA-A0D8-B6972C395A4A v2
281