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

1MRS757644 F
4.1.5.2
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4.1.5.4
620 series
Technical Manual

Function block

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Figure 154: Function block

Functionality

The three-phase voltage-dependent overcurrent protection function PHPVOC is used
for single-phase, two-phase or three-phase voltage-dependent time overcurrent
protection of generators against overcurrent and short circuit conditions.
The function starts when the input phase current exceeds a limit which is dynamically
calculated based on the measured terminal voltages. The operating characteristics can
be selected to be either inverse definite minimum time IDMT or definite time DT.
The function contains a blocking functionality. It is possible to block function outputs,
timers or the function itself, if desired.

Operation principle

The function can be enabled and disabled with the Operation setting. The
corresponding parameter values are "On" and "Off".
The operation of PHPVOC 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 155: Functional module diagram
Section 4
Protection functions
309