Load impedance limitation, with Phase selection with load
encroachment, quadrilateral characteristic function activated
The parameters for shaping of the load encroachment characteristic are found in the
description of Phase selection with load encroachment, quadrilateral characteristic
function (FRPSPDIS ,21).
Setting of minimum operating currents
The operation of Distance protection zone, quadrilateral characteristic (ZMQPDIS, 21)
can be blocked if the magnitude of the currents is below the set value of the parameter
IMinPUPP and IMinPUPG.
The default setting of IMinPUPP and IMinPUPG is 20% of IBase where IBase is the
chosen current for the analogue input channels. The value has been proven in practice
to be suitable in most of the applications. However, there might be applications where
it is necessary to increase the sensitivity by reducing the minimum operating current
down to 10% of IBase. This happens especially in cases, when the IED serves as a
remote back-up protection on series of very long transmission lines.
Setting IMinOpIR blocks the phase-to-ground loop if 3I
0
<IMinOpIR. The default
setting of IMinOpIR is 5% of IBase.
The minimum operating fault current is automatically reduced to 75% of its set value,
if the distance protection zone has been set for the operation in reverse direction.
Setting of timers for distance protection zones
The required time delays for different distance protection zones are independent of
each other. Distance protection zone 1 can also have a time delay, if so required for
selectivity reasons. Time delays for all zones can be set in a range of 0 to 60 seconds.
The tripping function of each particular zone can be inhibited by setting the
corresponding Operation parameter to Off. Different time delays are possible for the
phase-to-groundtPG and for the phase-to-phase tPP measuring loops in each distance
protection zone separately, to further increase the total flexibility of a distance protection.
3.6.9.3 Setting parameters
Table 74: ZMRPDIS (21) Group settings (basic)
Name
Values (Range) Unit Step Default Description
Operation Disabled
Enabled
- - Enabled Operation Disable / Enable
IBase 1 - 99999 A 1 3000 Base current, i.e. rated current
VBase 0.05 - 2000.00 kV 0.05 400.00 Base voltage, i.e. rated voltage
OperationDir Disabled
Non-directional
Forward
Reverse
- - Forward Operation mode of directionality NonDir /
Forw / Rev
Table continues on next page
1MRK504116-UUS C Section 3
IED application
339
Application manual
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