ABB Relion 670 Series Technical Reference Manual page 126

Section 5
Differential protection
120
• No operation of open CT algorithm
• Sensitive differential current level (Id>SensOperLev) which can be enable or
disable.
• Check zone differential operation can also supervise the trip output signal.
This feature can be enable or disabled.
These tripping conditions are then arranged in an AND gate in order to provide
final trip signal to the binary output contacts of the terminal.
The trip from differential zone can be either latched or self rest in accordance with
end user settings. Figure
protection.
55 shows the simplified internal trip logic for the busbar
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