8.18.3 Setting guidelines
The parameters for automatic switch onto fault logic, voltage- and current-based function
ZCVPSOF are set via the local HMI or Protection and Control Manager PCM600.
The distance protection zone used for instantaneous trip by ZCVPSOF has to be set to
cover the entire protected line with a safety margin of minimum 20%.
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 is used to select GBASVAL for reference of base values.
Operation: The operation of ZCVPSOF is by default set to On. The parameter must be set
to Off if ZCVPSOF is not to be used.
IPh< is used to set the current level for the detection of a dead line. IPh< is, by default, set
to 20% of IBase. It shall be set with a sufficient margin (15–20%) below the minimum
expected load current. In many cases, the minimum load current of a line is close to zero
and even can be zero. The operating value must exceed the maximum charging current of
an overhead line when only one phase is disconnected (mutual coupling in the other
phases).
UPh< is used to set the voltage level for the detection of a dead line. UPh< is, by default,
set to 70% of UBase. This is a suitable setting in most cases, but it is recommended to
check the suitability in the actual application.
AutoInitMode: automatic activating of ZCVPSOF is, by default, set to DLD disabled,
which means the dead-line logic detection is disabled. If an automatic activation of the
dead-line detection is required, the parameter AutoInitMode has to be set to either Voltage,
Current or Current & Voltage.
When AutoInitMode is set to Voltage, the dead-line detection logic checks that the three-
phase voltages are lower than the set UPh< level.
When AutoInitMode is set to Current, the dead-line detection logic checks if the three-
phase currents are lower than the set IPh< level.
When AutoInitMode is set to Current & Voltage, the dead-line detection logic checks that
both three-phase currents and three-phase voltages are lower than the set IPh< and UPh<
levels.
Otherwise, the logic is activated by an external BC input.
tSOTF: the drop delay of ZCVPSOF is, by default, set to 1.0 seconds, which is suitable for
most applications.
1MRK 506 369-UUS - Section 8
Impedance protection
Line distance protection REL670 2.2 ANSI 475
Application manual
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