Distance protection zones
M13841-10 v9
The design of the distance protection zones are presented for all measuring loops: phase-to-
ground as well as phase-to-phase.
Phase-to-ground related signals are designated by AG, BG and CG. The phase-to-phase signals are
designated by AB, BC and CA.
Fulfillment of two different measuring conditions is necessary to obtain the one logical signal for
each separate measuring loop:
• Zone measuring condition, which follows the operating equations described above.
• Group functional input signal (PHSEL), as presented in figure
77.
Two types of function block, ZMQPDIS (21) and ZMQAPDIS (21), are used in the IED. ZMQPDIS (21)
is used for zone 1 and ZMQAPDIS (21) for zone 2.
The PHSEL input signal represents a connection of six different integer values from Phase
selection with load encroachment, quadrilateral characteristic function FDPSPDIS (21) within the
IED, which are converted within the zone measuring function into corresponding boolean
expressions for each condition separately. Input signal PHSEL is connected to FDPSPDIS or
FMPSPDIS (21) function output PHSELZ.
The input signal DIRCND is used to give condition for directionality for the distance measuring
zones. The signal contains binary coded information for both forward and reverse direction. The
zone measurement function filters out the relevant signals depending on the setting of the
parameter
OperationDir
. It must be configured to the STDIR output on ZDRDIR (21D) function.
1MRK 502 066-UUS B Section 7
Impedance protection
193
Technical manual
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