ABB RELION REX640 Technical Manual page 576

Protection functions
controlled by a binary input, a horizontal communication input or an internal signal
of the protection relay's program. The influence of the BLOCK signal activation is
preselected with the global setting
The
mode, the operate timer is frozen to the prevailing value. In the "Block all" mode, the
whole function is blocked and the timers are reset. In the "Block OPERATE output"
mode, the function operates normally but the OPERATE output is not activated.
Recommended uses of the BLOCK input of MFADPSDE are:
1.
2.
3.
4.
The logic to release MFADPSDE at time of resistor (re)connection is illustrated in
Figure 332
• Detection of earth fault from residual overvoltage, ROVPTOV
• Delay of release MFADPSDE using TONGAPC connected to the BLOCK input of
MFA (inversed)
• Delay of release (TONGAPC: On delay time (ms)) based on known time delays in
resistor connection
• Protection operate delay time to be set smaller than the resistor connection
duration.
576
Blocking mode setting has three blocking methods. In the "Freeze timers"
If the BLOCK input of MFADPSDE is used in the configuration, then "Block
all" mode is recommended.
Connecting the start signal of non-directional earth fault protection (EFxPTOC),
set to operate in case of a cross-country fault, to BLOCK input of MFADPSDE
to reset phasor accumulation during a cross-country fault. MFADPSDE can then
adapt to a fault direction change more rapidly if a single-phase earth fault
persists in the system after the other faulty feeder has been tripped (the cross-
country fault has been transformed into a single-phase earth fault).
Connecting the 'Auto-Reclose in progress' output (INPRO) from DARREC to
BLOCK input of MFADPSDE to allow faster reset of MFADPSDE during high-
speed auto-reclosing cycle HSAR when setting
higher than the dead time of high-speed auto-reclosing cycle HSAR.
In case of a network with distributed coils but no centralized arc suppression
coil at the primary substation (unearthed network), it is recommended to add
an additional logic to protection configuration, which blocks MFADPSDE if the
frequency of measured Uo and Io becomes lower than nominal. Such condition
is valid in network when earth fault becomes disconnected and a phenomenon
called 'post-fault oscillation' is initiated.
If the parallel resistor of the coil has long connection delay, it is recommended
to add an additional logic to protection configuration to enable the release of
MFADPSDE at the time of the parallel resistor switching.
.
Blocking mode .
Reset delay time equals or is
1MRS759142 F
REX640
Technical Manual