ABB RELION Series, Technical Manual

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Section 3 Basic functions
3.1 Self-supervision
The protection relay's extensive self-supervision system continuously supervises the
software and the electronics. It handles run-time fault situation and informs the user
about a fault via the LHMI and through the communication channels.
There are two types of fault indications.
• Internal faults
• Warnings
3.1.1 Internal faults
When an internal relay fault is detected, relay protection operation is disabled, the
green Ready LED begins to flash and the self-supervision output contact is activated.
Internal fault indications have the highest priority on the LHMI. None
of the other LHMI indications can override the internal fault
indication.
An indication about the fault is shown as a message on the LHMI. The text
Internal Fault
with an additional text message, a code, date and time, is shown
to indicate the fault type.
Different actions are taken depending on the severity of the fault. The protection relay
tries to eliminate the fault by restarting. After the fault is found to be permanent, the
protection relay stays in the internal fault mode. All other output contacts are released
and locked for the internal fault. The protection relay continues to perform internal
tests during the fault situation.
If an internal fault disappears, the green Ready LED stops flashing and the protection
relay returns to the normal service state. The fault indication message remains on the
display until manually cleared.
The self-supervision signal output operates on the closed-circuit principle. Under
normal conditions, the protection relay is energized and the contact gaps 3-5 in slot
X100 is closed. If the auxiliary power supply fails or an internal fault is detected, the
contact gaps 3-5 are opened.
1MRS758755 A
Section 3
Basic functions
REC615 and RER615 45
Technical Manual