3.2.6.5 Voltage-dependent overcurrent protection PHPVOC
Two instances of voltage-dependent overcurrent function are used for protecting
generators against overcurrent and short-circuit conditions. The function operates
when the current exceeds a limit which is dynamically calculated based on the
measured terminal voltage.
The operating characteristics can be selected to be either inverse-definite minimum
time or definite-time characteristic. The set of three phase current and voltages, I3P
and U3P, are connected to the inputs.
A common operate and start signal from the both voltage-dependent overcurrent
functions is connected to an OR-gate to form a combined operate and start signal,
which provides a LED indication on the LHMI. Also a separate start and operate
signal from the both voltage-dependent overcurrent functions is connected to the
disturbance recorder.
The voltage-dependent overcurrent function is blocked on detection of fuse failure.
3.2.6.6 Directional earth-fault protection DEFxPDEF
The directional earth-fault protection functions are used for directional and non-
directional earth-fault protection with DT or IDMT characteristic when appropriate.
The configuration includes the high and low variants of the directional earth-fault
protection function. The configuration is developed considering that the core balance
CT is provided both on line- and neutral-side of the generator. The differential current
of the two neutral currents is made externally, and the resultant ∆Io current is
connected to the IED’s. The set of three-phase voltage and differential neutral current,
U3P and DIFF_Io, are connected to the inputs.
A common operate and start signal from both the directional earth-fault functions and
residual overvoltage protection are connected to an OR-gate to form a combined
earth-fault operate and start signal, which provides a LED indication on the LHMI.
Also separate start and operate signals from the both directional earth-fault functions
are connected to the disturbance recorder.
The directional earth-fault function is blocked on detection of fuse failure.
Section 3 1MRS757582 C
REG630 variants
34 REG630
Application Manual
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