Function Block; Functionality; Operation Principle - ABB RELION 620 Series Technical Manual

1MAC504801-IB E
4.2.4.2
4.2.4.3
4.2.4.4
620 series ANSI
Technical Manual

Function block

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Figure 130: Function block

Functionality

The negative-sequence overvoltage protection 47 is used to detect negative-sequence
overvoltage conditions. 47 is used for the protection of machines.
he function picks up when the negative-sequence voltage exceeds the set limit. 47 operates
with the definite time (DT) characteristics.
The function contains a blocking functionality. It is possible to block function outputs, the
definite timer or the function itself, if desired.

Operation principle

The function can be enabled and disabled with the Operation setting. The corresponding
parameter values are "Enable" and "Disable".
The operation of the negative-sequence overvoltage protection can be described using a
module diagram. All the modules in the diagram are explained in the next sections.
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Figure 131: Functional module diagram. V
sequence voltage.
Level detector
The calculated negative-sequence voltage is compared to the set Pickup value setting. If
the value exceeds the set Pickup value, the level detector enables the timer.
Protection functions
is used for representing negative phase
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