Function Range or value Accuracy
Dynamic overreach <5% at 85 degrees
measured with CVT’s
and 0.5<SIR<30
-
Definite time delay phase-
phase and phase-ground
operation
(0.000-60.000) s ±0.2% or ±40 ms whichever is greater
Trip time 25 ms typically IEC 60255-121
Reset ratio 105% typically -
Reset time at 0.1 x Zreach to 2
x Zreach
Min. = 20 ms
Max. = 50 ms
-
7.2 Phase selection, quadrilateral characteristic with fixed
angle FDPSPDIS (21)
IP12400-1 v3
7.2.1 Identification
7.2.1.1 Identification
M14850-1 v5
Function description IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Phase selection with load
encroachment, quadrilateral
characteristic
FDPSPDIS
SYMBOL-DD V1 EN-US
21
7.2.2 Functionality
M13139-3 v8
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. Phase selection, quadrilateral
characteristic with fixed angle FDPSPDIS 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, FDPSPDIS (21) has a built-in algorithm for load
encroachment, which gives 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.
1MRK 502 066-UUS B Section 7
Impedance protection
197
Technical manual
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