ABB 615 Series - Page 488

The BLOCK and BLOCK_LS input statuses affect only the behavior of the local protection
instance. When a line differential protection stage (stabilized low or instantaneous high)
is blocked, also the received remote signals related to the corresponding stage are ignored
(received direct inter-trip signals from the remote end). The binary signal transfer
functionality should therefore be used for transferring the possible additional blocking
information between the local and remote terminals whenever the blocking logic behavior
needs to be the same on both line ends.
Test mode
The line differential function in one protection relay can be set to test mode, that is, the
Operation setting is set to “test/blocked”. This blocks the line differential protection
outputs in the protection relay and sets the remote protection relay to a remote test mode,
such that the injected currents are echoed back with the shifted phase. It is also possible
that both protection relays are simultaneously in the test mode. When the line differential
protection function is in the test mode:
• The remote end protection relay echoes locally injected current samples back with the
shifted phase. The current samples that are sent to the remote protection relay are
scaled with the CT ratio correction setting.
• The operation of both stages (stabilized low or instantaneous high) are blocked, and
also the direct inter-trip functionality is blocked (both receive and send) in the
protection relay where the test mode is active.
• The remote end line differential protection function that is in the normal mode (On)
is not affected by the local end being in the test mode. This means that the remote end
function is operative but, at the same time, it ignores the received current samples
from the other end protection relay which is in the test mode.
• The PROT_ACTIVE output is false only in the protection relay that is currently in the
test mode.
87L
Local phasors
Local phasors
Time align PCSRTPC PCSRTPCSample latency Time align
I_INST_REM
I_INST_LOC
87L
I_INST_REM
I_INST_LOC
Operation ”On” Operation ”On”
CTratio
correction
CTratio
correction
CTratio
correction
CTratio
correction
Remote phasors Remote phasors
GUID-6B900ECD-6BB0-47D4-95F7-F7037FDBD6BA V1 EN
Figure 235: Operation during the normal operation of the line differential protection
Section 4 1MAC059074-MB A
Protection functions
482 615 series ANSI
Technical Manual