ABB REL670 2.2 IEC, Applications Manual

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8.18.2 Application
M13830-3 v6
Automatic switch onto fault logic, voltage- and current-based function ZCVPSOF
is a complementary function to impedance measuring functions, but may use the
information from such functions.
With ZCVPSOF, a fast trip is achieved for a fault on the whole line when the line is
being energized. The ZCVPSOF tripping is generally non-directional to secure a
trip at fault situations where directional information cannot be established, for
example, due to lack of polarizing voltage when a line potential transformer is
used.
Automatic activation based on dead-line detection can only be used when the
voltage transformer is situated on the line side of a circuit breaker.
When line side voltage transformers are used, the use of the nondirectional distance
zones secures switch onto fault tripping for close-in three-phase short circuits. The
use of the nondirectional distance zones also gives a fast fault clearance when
energizing a bus from the line with a short circuit fault on the bus.
Other protection functions like time-delayed phase and zero-sequence overcurrent
function can be connected to ZCVPSOF to increase the dependability in the
scheme.
When the voltage transformers are situated on the bus side, the automatic switch
onto fault detection based on dead-line detection is not possible. In such cases the
deadline detection is bypassed using the breaker closing status and the switch onto
fault logic is activated.
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
1MRK 506 369-UEN B
Section 8
Impedance protection
Line distance protection REL670 2.2 IEC 443
Application manual