ABB Relion REG670, Applications Manual

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When CHNGLCK has a logical one on its input, then all attempts to
modify the IED configuration and setting will be denied and the
message "Error: Changes blocked" will be displayed on the local
HMI; in PCM600 the message will be "Operation denied by active
ChangeLock". The CHNGLCK function should be configured so that
it is controlled by a signal from a binary input card. This guarantees
that by setting that signal to a logical zero, CHNGLCK is deactivated.
If any logic is included in the signal path to the CHNGLCK input, that
logic must be designed so that it cannot permanently issue a logical
one to the CHNGLCK input. If such a situation would occur in spite
of these precautions, then please contact the local ABB representative
for remedial action.
22.4 Denial of service SCHLCCH/RCHLCCH
22.4.1 Application
The denial of service functionality is designed to limit the CPU load that can be
produced by Ethernet network traffic on the IED. The communication facilities must
not be allowed to compromise the primary functionality of the device. All inbound
network traffic will be quota controlled so that too heavy network loads can be
controlled. Heavy network load might for instance be the result of malfunctioning
equipment connected to the network.
The functions Access point diagnostics function block measure the IED load from
communication and, if necessary, limit it for not jeopardizing the IEDs control and
protection functionality due to high CPU load. The function has the following denial
of service related outputs:
• LINKSTS indicates the Ethernet link status for the rear ports (single
communication)
• CHALISTS and CHBLISTS indicates the Ethernet link status for the rear ports
channel A and B (redundant communication)
• LinkStatus indicates the Ethernet link status for the front port
22.4.2 Setting guidelines
The function does not have any parameters available in the local HMI or PCM600.
1MRK 502 071-UEN -
Section 22
Security
Generator protection REG670 2.2 IEC and Injection equipment REX060, REX061, REX062 721
Application manual