Activated - ABB REL670 2.2 IEC Applications Manual

Section 8
Impedance protection
8.9.3.8
8.9.3.9
8.9.3.10
312
All this is applicable for all measuring zones when no Power swing detection
function ZMRPSB is activated in the IED. Use an additional safety margin of
approximately 20% in cases when a ZMRPSB function is activated in the IED,
refer to the description of Power swing detection function ZMRPSB.
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).
Setting of minimum operating currents
The operation of Distance protection zone, quadrilateral characteristic (ZMQPDIS)
can be blocked if the magnitude of the currents is below the set value of the
parameter IMinOpPP and IMinOpPE.
The default setting of IMinOpPP and IMinOpPE 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 IMinOpIN blocks the phase-to-earth loop if 3I
setting of IMinOpIN 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-earthtPE 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.
1MRK 506 369-UEN B
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Line distance protection REL670 2.2 IEC
Application manual