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 (FDPSPDIS, 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.
Directional impedance element for quadrilateral characteristics
The evaluation of the directionality takes place in Directional impedance quadrilateral
function ZDRDIR (21D). Equation
96 and equation 97 are used to classify that the
fault is in forward direction for phase-to-ground fault and phase-to-phase fault.
1 1
1
0.8 1 0.2 1
arg Re
L L M
L
V V
ArgDir ArgNeg s
I
× + ×
- < <
EQUATION1552 V2 EN (Equation 96)
For the AB element, the equation in forward direction is according to.
Section 3 1MRK504116-UUS C
IED application
184
Application manual
To Next Page
Loading...
