Zn = Vph / Iph
and three phase-to-phase loops according to
Zph-ph = Vph-ph / Iph-ph
The start operations from respective loop are binary coded into one word and provides
an output signal PLECND.
RLd
RLd
LdAngle
LdAngle
LdAngle
LdAngle
R
X
jX
Operation area Operation area
R
Operation area
No operation area No operation area
en06000414_ansi.vsd
ANSI06000414 V1 EN
Figure 154: Influence on the characteristic by load encroachment logic
Outputs
The output of the sequence components based phase selector and the delta logic phase
selector activates the output signals PU_A, PU_B and PU_C. If a ground fault is
detected the signal PHG_FLT gets activated.
The phase selector also gives binary coded signals that are connected to the zone
measuring element for opening the correct measuring loop(s). This is done by the
signal PHSCND. If only one phase is started (A, B or C), the corresponding phase-to-
ground element is enabled. PHG_FLT is expected to be made available for two-phase
and three-phase faults for the correct output to be selected. The fault loop is indicated
by one of the decimal numbers below.
The output PHSCND provides release information from the phase selection part only.
DLECND provides release information from the load encroachment part only.
PLECND provides release information from the phase selection part and the load
encroachment part combined, that is, both parts have to issue a release at the same time
(this signal is normally not used in the zone measuring element). In these signals, each
Section 6 1MRK505222-UUS C
Impedance protection
300
Technical reference manual
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