4.35
Date Code 20170814
Instruction Manual
SEL-700G Relay
Protection and Logic Functions
Group Settings (SET Command)
Figure 4.17
REF Enable Logic
Figure 4.18 illustrates the logic of the REF directional element, REF1F. It is at
this stage that the element decides whether to operate.
Figure 4.18
REF Directional Element
The directional element compares the polarizing current to the operating
current and indicates forward (internal) fault location or reverse (external)
fault location. The internal/forward indication occurs when the fault is within
the protected winding, between the terminal-end CTs and the neutral CT. The
relay converts appropriate terminal current to secondary in per unit of nominal
CT rating to form polarizing current, IPOL.
CTRX/CTRN • I
NNOM
• I
NNOM
is the nominal CT rating of the neutral CT.
• REF1POL = X when X_CUR_IN := TERM
REF1POL = Y when X_CUR_IN := NEUT
Relay
Word
Bits
Relay
Word
Bit
SEL
OGIC
Setting
Group
Setting
Group
Setting
1
/ I
NNOM
REF52BYP = YES
Relay
Word
Bit
50NREF1
50GREF1
CTRY/CTRN • I
NNOM
• I
NNOM
is the nominal CT rating of the neutral CT.
• REF1POL = X when X_CUR_IN := TERM
REF1POL = Y when X_CUR_IN := NEUT
REAL (I
POL
• I
OP*
)
m • |I
POL
| • |I
POL
| + c
REF1F
REF1R
Relay
Word
Bits
Relay
Word
Bit
1.5
cyc
0
1.5
cyc
0
CTRX/(CTRN • I
NNOM
)
CTRY/(CTRN • I
NNOM
)
1
/ I
NNOM
I
OP
Relay
Word
Bit
I
POL
Summary of Contents for SEL-700G Series
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