the possibility to enlarge the resistive setting of both
the phase selection and the measuring zones without
interfering with the load.
The extensive output signals from the phase selection
gives also important information about faulty phase(s)
which can be used for fault analysis.
A current-based phase selection is also included. The
measuring elements continuously measure three phase
currents and the residual current and, compare them
with the set values.
High speed distance protection, quadrilateral and
mho ZMFPDIS
GUID-2E34AB7F-886E-499F-8984-09041A89238D v10
The high speed distance protection (ZMFPDIS) provides
a sub-cycle, down towards a half-cycle operate time. Its
seven zone full scheme protection with three fault loops
for phase-to-phase faults and three fault loops for
phase-to-earth faults for each of the independent zones,
which makes the function suitable for applications with
single-phase autoreclosing.
Each measurement zone is designed with the flexibility
to operate in either quadrilateral or mho characteristic
mode. This can be decided separately for the phase-to-
ground or phase-to-phase loops. Out of the seven zones,
one zone has fixed directionality to reverse, one zone
has fixed directionality to forward, and five zone with
directionality independently settable to forward/
reverse/non-directional.
The operation of the phase-selection is primarily based
on a current change criteria (i.e. delta quantities),
however there is also a phase selection criterion
operating in parallel which bases its operation on
voltage and current phasors exclusively. Additionally,
the directional element provides a fast and correct
directional decision under difficult operating conditions,
including close-in three-phase faults, simultaneous
faults and faults with only zero-sequence in-feed.
During phase-to-earth faults on heavily loaded power
lines there is an adaptive load compensation algorithm
that prevents overreaching of the distance zones in the
load exporting end, improving the selectivity of the
function. This also reduces underreach in the importing
end.
High speed distance protection for series comp.
lines, quad and mho characteristic ZMFCPDIS
GUID-C5C1ADD8-50A5-4485-848C-77D2222B56DC v9
The high speed distance protection (ZMFCPDIS)
provides a sub-cycle, down towards a half-cycle operate
time. Its seven zone, full scheme protection concept is
entirely suitable in applications with single-phase
autoreclosing.
High speed distance protection ZMFCPDIS is
fundamentally the same function as ZMFPDIS but
provides more flexibility in zone settings to suit more
complex applications, such as series compensated lines.
In operation for series compensated networks, the
parameters of the directional function are altered to
handle voltage reversal.
Each measurement zone is designed with the flexibility
to operate in either quadrilateral or mho characteristic
mode. This can even be decided separate for the phase-
to-ground or phase-to-phase loops. The seven zones can
operate either independent of each other, or their start
can be linked (per zone) through the phase selector or
the first starting zone. This can provide fast operate
times for evolving faults.
The operation of the phase-selection is primarily based
on a current change criteria (i.e. delta quantities),
however there is also a phase selection criterion
operating in parallel which bases its operation on
voltage and current phasors exclusively. Additionally the
directional element provides a fast and correct
directional decision under difficult operating conditions,
including close-in three-phase faults, simultaneous
faults and faults with only zero-sequence in-feed.
During phase-to-earth faults on heavily loaded power
lines there is an adaptive load compensation algorithm
that prevents overreaching of the distance zones in the
load exporting end, improving the selectivity of the
function. This also reduces underreach in the importing
end.
The ZMFCPDIS function has another directional element
with phase segregated outputs STTDFwLx and
STTDRVLx (where, x = 1-3) based on the transient
components. It provides directionality with high speed,
dependability and security, which is also suitable for
extra high voltage and series compensated lines where
the fundamental frequency signals are distorted.
Power swing detection, blocking and unblocking
ZMBURPSB
GUID-DB043AB6-E571-4DCB-B899-663D13AFDE2E v1
Power swings may occur after disconnection of heavy
loads or trip of big generation plants.
Power swing detection, blocking and unblocking
function (ZMBURPSB ) is used to detect power swings
and initiate blocking of all distance protection zones.
Also, fault identification and its classification for
various types of fault occurrences during the power
swing are available in the ZMBURPSB function. So, six
measuring loops used in each distance protection
zone, if blocked during power swing, can be unblocked/
released for distance measurement depending upon the
Line differential protection RED670
1MRK 505 379-BEN N
36 Hitachi Power Grids
© Copyright 2017 Hitachi Power Grids. All rights reserved
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