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).
Common base IED values for primary current (IBase), primary voltage (UBase) and
primary power (SBase) are set in the global base values for settings function
GBASVAL.
GlobalBaseSel: This is used to select GBASVAL function for reference of base values.
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
260.
NumPhSel: Number of phases, with high current, required for operation. The setting
possibilities are: 1 out of 3, 2 out of 3 and 3 out of 3. The default setting is 1 out of 3.
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 IB.
2ndHarmStab: Operate level of 2nd harmonic current restrain set in % of the
fundamental current. The setting range is 5 - 100% in steps of 1%. The default setting
is 20%.
1MRK 504 163-UUS A Section 9
Current protection
Transformer protection RET670 2.2 ANSI 521
Application manual
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