Setting Guidelines - ABB Relion 670 Series Applications Manual

1MRK 511 358-UUS A
motor. Therefore there is a possibility to give a setting of a multiplication factor to the current
pick-up level. This multiplication factor is activated from a binary input signal to the function.
Power transformers can have a large inrush current, when being energized. This phenomenon is
due to saturation of the transformer magnetic core during parts of the period. There is a risk that
inrush current will reach levels above the pick-up current of the phase overcurrent protection. The
inrush current has a large 2nd harmonic content. This can be used to avoid unwanted operation of
the protection. Therefore, OC4PTOC (51/67) have a possibility of 2nd harmonic restrain if the level
of this harmonic current reaches a value above a set percentage of the fundamental current.
The phase overcurrent protection is often used as protection for two and three phase short
circuits. In some cases it is not wanted to detect single-phase ground faults by the phase
overcurrent protection. This fault type is detected and cleared after operation of ground fault
protection. Therefore it is possible to make a choice how many phases, at minimum, that have to
have current above the pick-up level, to enable operation. If set
current in one phase only. If set
7.2.3

Setting guidelines

The parameters for the directional phase overcurrent protection, four steps OC4PTOC (51/67) are
set via the local HMI or PCM600.
The following settings can be done for OC4PTOC (51/67).
GlobalBaseSel : Selects the global base value group used by the function to define ( IBase ), ( VBase )
and ( SBase ).
MeasType : Selection of discrete Fourier filtered ( DFT ) or true RMS filtered ( RMS ) signals. RMS is
used when the harmonic contents are to be considered, for example in applications with shunt
capacitors.
Operation : The protection can be set to Enabled or Disabled .
AngleRCA : Protection characteristic angle set in degrees. If the angle of the fault loop current has
the angle RCA, the direction to the fault is forward.
AngleROA : Angle value, given in degrees, to define the angle sector of the directional function,
shown in Figure 55.
NumPhSel : Number of phases, with high current, required for operation. The setting possibilities
1 out of 3 , 2 out of 3 and 3 out of 3 . The default setting is 1 out of 3 .
are:
PUMinOpPhSel : Minimum current setting level for releasing the directional start signals in % of IB .
This setting should be less than the lowest step setting. The default setting is 7% of
2ndHarmStab : Operate level of 2nd harmonic current restrain set in % of the fundamental current.
The setting range is
Application manual
2 of 3 or 3 of 3 single-phase ground faults are not detected.
When inverse time overcurrent characteristic is selected, the trip time of the stage
will be the sum of the inverse time delay and the set definite time delay. Thus, if
only the inverse time delay is required, it is important to set the definite time delay
for that stage to zero.
5 - 100 % in steps of 1%. The default setting is 20%.
Current protection
1 of 3 it is sufficient to have high
IB .
Section 7
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M12982-4 v14
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