ABB RELION 670 SERIES Applications Manual page 263

Line distance protection

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Table of Contents

1MRK 506 369-UUS -

Line distance protection REL670 2.2 ANSI

Application manual

IEC06000403 V1 EN

Load encroachment phenomena and shaped load encroachment

characteristic

The Faulty phase identification with load encroachment for mho (FMPSPDIS, 21)

function shapes the characteristic according to the diagram on the right in figure 126. The

load encroachment algorithm will increase the possibility to detect high fault resistances,

especially for phase-to-ground faults at remote line end. For example, for a given setting

of the load angle LdAngle (see figure 127) for the Faulty phase identification with load

encroachment for mho function (FMPSPDIS, 21), the zone reach can be expanded

according to the diagram on the right in figure

without risk for unwanted operation due to load encroachment. The part of the load

encroachment sector that comes inside the mho circle will not cause a trip if FMPSPDIS

(21) is activated for the zone measurement. This is valid in both directions.

given higher fault resistance coverage

Impedance protection

en06000403.vsd