Trip-Circuit Supervision; Self-Supervision; Current Circuit Supervision; Protection Communication And Supervision - ABB RED615 Product Manual

ABB
Line Differential Protection and Control
RED615
Product version: 2.0
signal of a protection block, or by both. The
available measurement modes include DFT,
RMS and peak-to-peak. In addition, the
maximum demand current with time stamp is
separately recorded. By default, the records
are stored in a non-volatile memory.
11. Trip-circuit
supervision
The trip-circuit supervision continuously
monitors the availability and operability of
the trip circuit. It provides open-circuit
monitoring both when the circuit breaker is
in its closed and in its open position. It also
detects loss of circuit-breaker control voltage.

12. Self-supervision

The IED's built-in self-supervision system
continuously monitors the state of the IED
hardware and the operation of the IED
software. Any fault or malfunction detected
will be used for alerting the operator. A
permanent IED fault will block the protection
functions to prevent incorrect operation.
13. Current circuit
supervision
The IED includes current circuit supervision.
Current circuit supervision is used for
detecting faults in the current transformer
secondary circuits. On detecting of a fault the
current circuit supervision function activates
an alarm LED and blocks the line differential
protection and negative sequence overcurrent
protection functions to avoid unintended
operation. The current circuit supervision
function calculates the sum of the phase
currents from the protection cores and
compares the sum with the measured single
reference current from a core balance current
transformer or from separate cores in the
phase current transformers
14. Protection
communication and
supervision
The communication between the IEDs is
enabled by means of a dedicated fibre-optic
communication channel. 1300 nm multi-mode
or single-mode fibres with LC connectors are
used for line differential communication. The
channel is used for transferring the phase
segregated current value data between the
IEDs. The current phasors from the two IEDs,
geographically located apart from each other,
must be time coordinated so that the current
differential algorithm can be executed
correctly. The so called echo method is used
for time synchronization. No external devices
such as GPS clocks are thereby needed for
the line differential protection communication.
The communication channel is further used
for binary signal transfer (BST), transferring
of user configurable binary information,
between the IEDs. There are a total of eight
BST signals available for user definable
purposes. The BST signals can originate from
the IED's binary inputs or internal logics, and
be assigned to the remote IED's binary
outputs or internal logics.
The protection communication supervision
continuously monitors the protection
communication link. The IED immediately
blocks the line differential protection function
in case that severe interference in the
communication link, risking the correct
operation of the function, is detected. An
alarm signal will eventually be issued if the
interference, indicating permanent failure in
the protection communication, persists. The
1MRS756500 B
Issued: 03.07.2009
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