Faulty phase identification with load encroachment
FMPSPDIS
SEMOD153825-5 v7
The ability to accurately and reliably classify different
types of fault so that single phase tripping and
autoreclosing can be used plays an important roll in
today's power systems.
The phase selection function is design to accurately
select the proper fault loop(s) in the distance function
dependent on the fault type.
The heavy load transfer that is common in many
transmission networks may in some cases interfere with
the distance protection zone reach and cause unwanted
operation. Therefore the function has a built in
algorithm for load encroachment, which gives the
possibility to enlarge the resistive setting of the
measuring zones without interfering with the load.
The output signals from the phase selection function
produce important information about faulty phase(s),
which can be used for fault analysis as well.
Distance measuring zone, quad characteristic
separate Ph-Ph and Ph-E settings ZMRPDIS,
ZMRAPDIS
GUID-014501E7-EE0D-440F-8DC8-C44B848E49D3 v4
The line distance protection is up to five zone full
scheme protection with three fault loops for phase-to-
phase faults and three fault loops for phase-to-earth
fault for each of the independent zones. Individual
settings for each zone in resistive and reactive reach
gives flexibility for use as back-up protection for
transformer connected to overhead lines and cables of
different types and lengths.
Mho alternative quadrilateral characteristic is available.
Distance protection zone, quadrilateral characteristic
(ZMRPDIS) together with Phase selection, quadrilateral
characteristic with settable angle (FRPSPDIS) has
functionality for load encroachment, which increases the
possibility to detect high resistive faults on heavily
loaded lines, as shown in figure
15.
en05000034.vsd
R
X
Forward
operation
Reverse
operation
IEC05000034 V1 EN-US
Figure 15. Typical quadrilateral distance protection zone with
Phase selection, quadrilateral characteristic with
settable angle function FRPSPDIS activated
The independent measurement of impedance for each
fault loop together with a sensitive and reliable built-in
phase selection makes the function suitable in
applications with single pole tripping and autoreclosing.
Built-in adaptive load compensation algorithm prevents
overreaching of zone 1 at load exporting end at phase-
to-earth faults on heavily loaded power lines.
The distance protection zones can operate, independent
of each other, in directional (forward or reverse) or non-
directional mode. This makes them suitable, together
with different communication schemes, for the
protection of power lines and cables in complex network
configurations, such as parallel lines, multi-terminal
lines and so on.
Phase selection, quadrilateral characteristic with
settable angle FRPSPDIS
GUID-09D0E480-C003-424E-BECD-A82BCB0052CD v1
The operation of transmission networks today is in
many cases close to the stability limit. Due to
environmental considerations, the rate of expansion and
reinforcement of the power system is reduced for
example, difficulties to get permission to build new
power lines. The ability to accurately and reliably classify
the different types of fault, so that single pole tripping
and autoreclosing can be used plays an important role in
this matter. The phase selection function is designed to
accurately select the proper fault loop in the distance
function dependent on the fault type.
The heavy load transfer that is common in many
transmission networks may make fault resistance
coverage difficult to achieve. Therefore, the function has
a built in algorithm for load encroachment, which gives
Line differential protection RED670
1MRK 505 379-BEN N
Hitachi Power Grids 35
© Copyright 2017 Hitachi Power Grids. All rights reserved
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