Alstom MiCOM P54 Series, Technical Manual

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Application Notes P54x/EN AP/La4
MiCOM P543, P544, P545 & P546
(AP) 6-15
AP
2.3.5 Selection of distance operating characteristic (Distance option only)
In general, the following characteristics are recommended:

Short line applications: Mho phase fault and quadrilateral earth fault zones.

Open delta (vee-connected) VT applications: Mho phase fault, with earth fault distance
disabled , and directional earth fault only used for earth fault protection.

Series compensated lines: Recommend always to use mho characteristics for both
phase and earth faults.
2.3.5.1 Phase characteristic (Distance option only)
This phase characteristic selection is common to all zones, allowing mho or quadrilateral
selection. Generally, the characteristic chosen will match the utility practice. If applied for
line protection similarly to LFZP Optimho, LFZR, SHNB Micromho or SHPM Quadramho
models in the ALSTOM Grid range, a mho selection is recommended. For cable
applications, or to set similarly to the MiCOM P441/442/444 models, a quadrilateral selection
is recommended.
Figure 2 shows the basic settings needed to configure a forward-looking mho zone,
assuming that the load blinder is enabled. Figure 3 shows the basic settings needed to
configure a forward-looking quadrilateral zone (blinder not shown).
P172 5 ENa
Zo n e Re a ch Z
B l in der R a d ius
Load
Blinder
Angle b
Variable mho
expansion by
polarizing ratio
Time
Delay
t
Line
Angle
Figure 2 Settings required to apply a Mho zone (Distance option only)