ABB RET670 - Page 680

T1
T2 T3
99000952.VSD
V
1
V
2
V
3
Z
1
Z
2
Z
3
I
1
I
2
I
3
=0
I
L
=I
1
+I
2
ANSI99000952 V1 EN
Figure 286: Disconnection of one transformer in a parallel group
When the busbar arrangement is more complicated with more buses and bus couplers/
bus sections, it is necessary to engineer a specific station topology logic. This logic can
be built in the application configuration in PCM600 and will keep record on which
transformers that are in parallel (in one or more parallel groups). In each TR8ATCC
(90) function block there are eight binary inputs (T1INCLD,..., T8INCLD) that will be
activated from the logic depending on which transformers that are in parallel with the
transformer to whom the TR8ATCC (90) function block belongs.
TR8ATCC (90) function block is also fitted with eight outputs (T1PG,..., T8PG) for
indication of the actual composition of the parallel group that it itself is part of. If
parallel operation mode has been selected in the IED with setting TrfId = Tx, then the
TxPG signal will always be set to 1. The parallel function will consider communication
messages only from the voltage control functions working in parallel (according to the
current station configuration). When the parallel voltage control function detects that
no other transformers work in parallel it will behave as a single voltage control
function in automatic mode.
Exchange of information between TR8ATCC functions
Each transformer in a parallel group needs an Automatic voltage control for tap
changer, parallel control TR8ATCC (90) function block of its own for the parallel
voltage control. Communication between these TR8ATCCs (90) is made either on the
GOOSE interbay communication on the IEC 61850 protocol if TR8ATCC (90)
functions reside in different IEDs, or alternatively configured internally in one IED if
multiple instances of TR8ATCC (90) reside in the same IED. Complete exchange of
TR8ATCC (90) data, analog as well as binary, on GOOSE is made cyclically every
300 ms.
TR8ATCC (90) function block has an output ATCCOUT. This output contains two
sets of signals. One is the data set that needs to be transmitted to other TR8ATCC (90)
blocks in the same parallel group, and the other is the data set that is transferred to the
Section 3 1MRK504116-UUS C
IED application
674
Application manual