17.1.2.2 Single- and/or three-pole tripping
M14828-11 v6
The single-/three-pole tripping operation mode will give single-
pole tripping for
single-phase faults and three-pole tripping for multi-phase fault. This operating mode is
always used together with a single-phase autoreclosing scheme.
The single-pole tripping can include different options and the use of the different inputs
in the function block. Inputs TRINP_A, TRINP_B and TRINP_C shall be used for trip
signals from functions with built-in pole selection logic such as distance or line
differential protection functions.
The inputs 1PTRZ and 1PTRGF are used for single-pole tripping from functions which
do not have built-in pole selection logic:
• 1PTRZ can be connected to the carrier aided trip signal from the distance
protection scheme (it means that another distance protection function has seen or
detected the fault)
• 1PTRGF can be connected to an earth fault function such as EF4PTOC or a carrier
aided trip signal from the earth fault protection scheme
These two inputs are combined with the external phase selection logic. Phase selection
signals from the external phase selector must be connected to the inputs PS_A, PS_B
and PS_C to achieve the tripping on the respective single-pole trip outputs TR_A,
TR_B and TR_C. The output TRIP is a general trip and is always activated
independent of which phase is involved. Depending on which phases are involved the
outputs TR1P, TR2P and TR3P will be activated as well.
When single-pole tripping schemes are used, a single-phase autoreclosing attempt is
expected to follow. For cases where the autoreclosing is not in service or will not
follow for some reason, the input prepare three-pole trip P3PTR must be activated.
This input is normally connected to the output PREP3P on the autorecloser function
SMBRREC (79) but can also be connected to other signals, for example, an external
logic signal. If two circuit breakers are involved, one SMPPTRC block instance and
one SMBRREC (79) instance are used for each circuit breaker. This will ensure correct
operation and behavior of each circuit breaker.
The output TR3P must be connected to the input TR3P on the SMBRREC (79)
function in order to switch SMBRREC (79) to perform a three-pole reclosing. If this
signal is not activated, SMBRREC will use single-pole dead time.
If a second line protection is utilizing the same SMBRREC (79), the
three-pole trip signal must be generated as OR conditions from both
line protections.
1MRK 504 163-UUS A Section 17
Logic
Transformer protection RET670 2.2 ANSI 841
Application manual
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