Areva MiCOM P441, Technical Manual

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P44x/EN AD/E44 Update Documentation
Page 30/82
MiCOM P441, P442 & P444
2.7.1 Settings table:
•
Remark: New settings from C1.x dealing with the tilt and the evolving forward zone
detection to zone1 (to avoid a Z1 detection in case of impedance locus getting out
from the quad (due to remote CB operating) but crossing the Z1 before being out from
the quad (with enough points that a Z1 decision can be confirmed if that timer has
been set to 0ms)
2.7.2.1 Zone Logic :
Remark Fig 3: Explanation about the symbols used in the logical schemas.
Represent an internal logic status from the logic of the protection (« the line is dead » or
« the pole is dead »)
Represent a setting adjusted or selected by MiCOM S1
Represent a command / a logical external status linked to an opto input from the protection
2.7.7 Resistive Reach Calculation – Earth fault element :
…/…
However, where Power Swing is used, a larger impedance surrounds zone 3 and zone 4 ,
a,d it is essential also, that load does not encroach upon the characteristic.(With previous
version)
Since version C1.x there is an earth detection criteria (10% IN + 5% IphaseMax) which
blocks the start of the relay if not enough residual current has been detected (it
secures the start in case of load encroachment for Deltas algorithms).
Another improvement since C1.x in the Power Swing detection is made by using
Phase-Phase detector. In that case phase ground start can be bigger from the
previous version, because the band
∆
R is applied only to the phase phase loop.