ABB RET670 Applications Manual page 675

1MRK504116-UUS C
Application manual
When the circulating current method is used, it is also possible to manually control the
transformers as a group. To achieve this, the setting OperationAdapt must be set
Enabled, then the control mode for one TR8ATCC (90) shall be set to "Manual" via
the binary input MANCTRL or the local HMI under Main menu/Control/Commands/
TransformerVoltageControl(ATCC,90)/TR8ATCC:x whereas the other
TR8ATCCs (90) are left in "Automatic". TR8ATCCs (90) in automatic mode will then
observe that one transformer in the parallel group is in manual mode and will then
automatically be set in adapt mode. As the name indicates they will adapt to the
manual tapping of the transformer that has been put in manual mode.
TR8ATCC (90) in adapt mode will continue the calculation of V
to the measured busbar voltage, it will compare it with the deadband DV.
adding V
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The following control rules are used:
1.
If V is positive and its modulus is greater thanDV, then initiate an VLOWER
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command. Tapping will then take place after appropriate t1/t2 timing.
is negative and its modulus is greater than DV, then initiate an VRAISE
2.
If V
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command. Tapping will then take place after appropriate t1/t2 timing.
3.
If V modulus is smaller thanDV, then do nothing.
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The binary output signal ADAPT on the TR8ATCC (90) function block will be
activated to indicate that this TR8ATCC (90) is adapting to another TR8ATCC (90) in
the parallel group.
It shall be noted that control with adapt mode works as described under the condition
that only one transformer in the parallel group is set to manual mode via the binary
input MANCTRL or, the local HMI Main menu/Control/Commands/
TransformerVoltageControl(ATCC,90)/TR8ATCC:x.
In order to operate each tap changer individually when the circulating current method
is used, the operator must set each TR8ATCC (90) in the parallel group, in manual.
Adapt mode (operation with the master follower method)
When in master follower mode, the adapt situation occurs when the setting
OperationAdapt is Enabled, and the master is put in manual control with the followers
still in parallel master-follower control. In this situation the followers will continue to
follow the master the same way as when it is automatic control.
If one follower in a master follower parallel group is put in manual mode, still with the
setting OperationAdaptEnabled, the rest of the group will continue in automatic master
follower control. The follower in manual mode will of course disregard any possible
tapping of the master. However, as one transformer in the parallel group is now
exempted from the parallel control, the binary output signal ADAPT on TR8ATCC
(90) function block will be activated for the rest of the parallel group.
Section 3
IED application
, but instead of
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