Application - ABB RELION Series Technical Manual

1MRS758755 A
4.1.4.5
4.1.4.6
REC615 and RER615
Technical Manual
The timer calculates the start duration value START_DUR, which indicates the
percentage ratio of the start situation and the set operating time. The value is available
through the monitored data view.
The BLOCK signal blocks the operation of the function and resets the timer.

Application

In some cases, smaller distribution power transformers are used where the high-side
protection involves only power fuses. When one of the high-side fuses blows in a
single-phase condition, knowledge of it on the secondary side is lacking. The resulting
negative-sequence current leads to a premature failure due to excessive heating and
breakdown of the transformer insulation. Knowledge of this condition when it occurs
allows for a quick fuse replacement and saves the asset.
The Current block value setting can be set to zero to not block PHPTUC with a low
three-phase current. However, this results in an unnecessary event sending when the
transformer or protected object is disconnected.
Phase-specific start and operate can give a better picture about the evolving faults
when one phase has started first and another follows.
PHPTUC is meant to be a general protection function, so that it could be used in other
cases too.
In case of undercurrent-based motor protection, see the Loss of load protection.
Signals
Table 277: PHPTUC Input signals
Name Type
I_A SIGNAL
I_B SIGNAL
I_C SIGNAL
BLOCK BOOLEAN
Table 278: PHPTUC Output signals
Name Type
OPERATE BOOLEAN
OPR_A BOOLEAN
OPR_B BOOLEAN
OPR_C BOOLEAN
START BOOLEAN
ST_A BOOLEAN
ST_B BOOLEAN
ST_C BOOLEAN
Protection functions
Default Description
0 Phase A current
0 Phase B current
0 Phase C current
0=False Block all binary outputs by resetting timers
Description
Operate
Operate phase A
Operate phase B
Operate phase C
Start
Start phase A
Start phase B
Start phase C
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