8.18.3 Setting guidelines
M13855-4 v10
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.
1MRK 504 163-UUS A Section 8
Impedance protection
Transformer protection RET670 2.2 ANSI 489
Application manual
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