ABB REG670 - Simplified Logic Diagrams

X
R
ArgDir
ArgNegRes
ZPE
ZRevPE
UL1
ϕ
IL1
en06000470.eps
IEC06000470 V1 EN
Figure 73: Simplified characteristic for offset mho in reverse direction for L1-to-
earth fault
7.1.6.5 Simplified logic diagrams
Distance protection zones
The design of the distance protection zones are presented for all measuring loops:
phase-to-earth as well as phase-to-phase.
Phase-to-earth related signals are designated by L1N, L2N and L3N. The phase-to-
phase signals are designated by L1L2, L2L3, and L3L1.
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 (STCND), as presented in figure
74.
The ZMHPDIS function block is used in the IED for each zone.
The STCND input signal represents a connection of six different integer values from
Phase selection with load encroachment function FMPSPDIS within the IED, which
1MRK502052-UEN B Section 7
Impedance protection
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Technical manual