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

1MAC504801-IB E
4.2.3.2
4.2.3.3
4.2.3.4
620 series ANSI
Technical Manual

Function block

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Figure 128: Function block

Functionality

The residual overvoltage protection 59G/N is used in distribution networks where the
ground overvoltage can reach non-acceptable levels in, for example, high impedance
grounding.
The function picks up when the ground voltage exceeds the set limit. 59G/N operates with
the definite time (DT) characteristic.
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 residual overvoltage protection can be described by using a module
diagram. All the modules in the diagram are explained in the next sections.
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Figure 129: Functional module diagram. VG represents the ground voltage.
Section 4
Protection functions
283