ABB RER670 - Page 317

The transformers controlled in parallel with the circulating current method or the
master-follower method must be assigned unique identities. These identities are
entered as a setting in each TR8A
TCC, and they are predefined as T1, T2, T3,...,
T8 (transformers 1 to 8). In figure
133 there are three transformers with the
parameter TrfId
set to T1, T2 and T3, respectively.
For parallel control with the circulating current method or the master-follower
method alternatively, the same type of data set as described above, must be
exchanged between two TR8ATCC. To achieve this, each TR8ATCC is
transmitting its own data set on the output ATCCOUT as previously mentioned. To
receive data from the other transformers in the parallel group, the output
ATCCOUT from each transformer must be connected (via GOOSE or internally in
the application configuration) to the inputs HORIZx (x = identifier for the other
transformers in the parallel group) on TR8ATCC function block. Apart from this,
there is also a setting in each TR8ATCC =/,..., =/T1RXOP=Off/On,...,
T8RXOP=Off/ On. This setting determines from which of the other transformer
individuals that data shall be received. Settings in the three TR8ATCC blocks for
the transformers in figure
133, would then be according to the table 31:
Table 31: Setting of TxRXOP
TrfId=T1 T1RXOP=
Off
T2RXOP=
On
T3RXOP=
On
T4RXOP=
Off
T5RXOP=
Off
T6RXOP=
Off
T7RXOP=
Off
T8RXOP=
Off
TrfId=T2 T1RXOP=
On
T2RXOP=
Off
T3RXOP=
On
T4RXOP=
Off
T5RXOP=
Off
T6RXOP=
Off
T7RXOP=
Off
T8RXOP=
Off
TrfId=T3 T1RXOP=
On
T2RXOP=
On
T3RXOP=
Off
T4RXOP=
Off
T5RXOP=
Off
T6RXOP=
Off
T7RXOP=
Off
T8RXOP=
Off
Observe that this parameter must be set to Off for the “own” transformer. (for
transformer with identity T1 parameter T1RXOP
must be set to Off, and so on.
Blocking
SEMOD159053-275 v2
Blocking conditions
SEMOD159053-277 v6
The purpose of blocking is to prevent the tap changer from operating under
conditions that can damage it, or otherwise when the conditions are such that
power system related limits would be exceeded or when, for example the
conditions for automatic control are not met.
For the Automatic voltage control for tap changer function, TR1ATCC for single
control and TR8ATCC for parallel control, three types of blocking are used:
Partial Block: Prevents operation of the tap changer only in one direction (only
URAISE or ULOWER command is blocked) in manual and automatic control
mode.
Auto Block: Prevents automatic voltage regulation, but the tap changer can still be
controlled manually.
1MRK 506 375-UEN A Section 12
Control
Railway application RER670 2.2 IEC 311
Application manual