ABB RER620

1MAC309294-MB F Section 3
Basic functions
RER620 45
Technical Manual
3.2 Self-supervision
The 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 communications channels.
There are two types of fault indications.
• Internal faults
• Warnings
3.2.1 Internal faults
When a relay internal fault is detected, the green Normal LED begins to flash and the
self-supervision output contact is activated.
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 relay tries to
eliminate the fault by restarting. After the fault is found to be permanent, the relay stays in
internal fault mode. All other output contacts are released and locked for the internal fault.
The relay continues to perform internal tests during the fault situation.
If an internal fault disappears, the green Normal LED stops flashing and the relay returns
to the normal service state. The fault indication message remains on the LCD until
manually cleared.
The self-supervision signal output operates on the closed circuit principle. Under normal
conditions the relay is energized and the contact gap 3-5 in slot X100 is closed. If the
auxiliary power supply fail or an internal fault is detected, the contact gap 3-5 is opened.
Internal fault indications have the highest priority on the LHMI. None of
the other LHMI indications can override the internal fault indication.