Alstom MiCOM P54 Series, Technical Manual

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P54x/EN AP/La4 Application Notes
(AP) 6-14
MiCOM P543, P544, P545 & P546
AP
2.2 Optional distance protection
The MiCOM P54x has, by ordering option, a comprehensive integrated distance protection
package. This comprises :-

Phase fault distance protection

Earth/ground fault distance protection

Power sing detection, alarm, and blocking

Out-of-step detection and tripping

Switch on to fault (SOTF) and trip on reclose (TOR)

Directional Schemes

Aided schemes
These are described in the following sections and are marked as being applicable to the
distance option only. If the distance option is not specified, these will not be applicable, and
additional protection will be in the form of overcurrent etc., as described from section 2.6.
2.3 Distance protection and aided DEF (Distance option only)
2.3.1 Simple and advanced setting mode (Distance option only)
To the benefit of user, the MiCOM P54x offers two setting modes for distance protection:
“
Simple
” and “
Advanced
”. In the majority of cases, “Simple” setting is recommended, and
allows the user merely to enter the line parameters such as length, impedances and residual
compensation. Then, instead of entering distance zone impedance reaches in ohms, zone
settings are entered in terms of
percentage of the protected line . This makes the relay
particularly suited to use along with any installed LFZP Optimho relays, as the reduced
number of settings mimics the Autocalc facility within Opticom software.
The “
Advanced
” setting mode is recommended for the networks where the protected and
adjacent lines are of dissimilar construction, requiring independent zone characteristic
angles and residual compensation. In this setting mode all individual distance ohmic reach
and residual compensation settings and operating current thresholds per each zone are
accessible. This makes the relay adaptable to any specific application.
2.3.2 Line parameters settings (Distance option only)
It is essential (especially when using the “simple” setting mode) that the data relating to
100% of the protected line is entered here. Take care to input the Line Impedance that
correctly corresponds to either Primary or Secondary, whichever has been chosen as the
basis for Settings Values in the Configuration column.
2.3.3 Residual compensation for earth/ground faults (Distance option only)
For earth faults, residual current (derived as the vector sum of phase current inputs
(Ia + Ib + Ic) is assumed to flow in the residual path of the earth loop circuit. Therefore, the
earth loop reach of any zone must generally be extended by a multiplication factor of (1 +
kZN) compared to the positive sequence reach for the corresponding phase fault element.
Caution: The kZN Angle is different than previous LFZP, SHNB, and LFZR relays:
When importing settings from these older products, subtract. angle

Z
1
.
2.3.4 Mutual compensation for parallel lines (Distance option only)
Typically a mutual cut off factor of 1.5 is chosen to give a good margin of safety between the
requirements of correct mutual compensation for faults inside the protected line and
eliminating misoperations for faults on the adjacent line.