GE UR Series L90, Instruction Manual

Page: 569 / 846

GE Multilin L90 Line Current Differential System 9-23
9 THEORY OF OPERATION 9.3 DISTANCE ELEMENTS
9
The ground elements are polarized from either zero-sequence or negative-sequence current as per user-settings to maxi-
mize performance in non-homogenous systems. The polarizing current is additionally shifted by the user-selectable non-
homogeneity correction angle.
f) REVERSE QUADRILATERAL REACTANCE CHARACTERISTIC FOR NON-DIRECTIONAL APPLICATIONS
The reverse quadrilateral reactance characteristic is achieved by checking the angle between:
AB phase element: (I
A
– I
B
)

Z
REV
– (V
A
– V
B
) and (I
A
– I
B
)

Z
REV
BC phase element: (I
B
– I
C
)

Z
REV
– (V
B
– V
C
) and (I
B
– I
C
)

Z
REV
CA phase element: (I
C
– I
A
)

Z
REV
– (V
C
– V
A
) and (I
C
– I
A
)

Z
REV
A ground element: I
A

Z + I_0

K0

Z
REV
+ I
G

K0M

Z
REV
– V
A
and (j

I_0 or j

I_2A)

e
j(180 +

)
B ground element: I
B

Z + I_0

K0

Z
REV
+ I
G

K0M

Z
REV
– V
B
and (j

I_0 or j

I_2B)

e
j(180 +

)
C ground element: I
C

Z + I_0

K0

Z
REV
+ I
G

K0M

Z
REV
– V
C
and (j

I_0 or j

I_2C)

e
j(180 +

)
The ground elements are polarized from either zero-sequence or negative-sequence current as per user-settings to maxi-
mize performance in non-homogenous systems. The polarizing current is additionally shifted by the user-selectable non-
homogeneity correction angle.
g) DIRECTIONAL CHARACTERISTIC
The directional characteristic is achieved by checking the angle between:
AB phase element: (I
A
– I
B
)

Z
D
and (V
A
– V
B
)_1M
BC phase element: (I
B
– I
C
)

Z
D
and (V
B
– V
C
)_1M
CA phase element: (I
C
– I
A
)

Z
D
and (V
C
– V
A
)_1M
A ground element: I_0

Z
D
and V
A
_1M
I
A
_2

Z
D
and V
A
_1M
B ground element: I_0

Z
D
and V
B
_1M
I
B
_2

Z
D
and V
B
_1M
C ground element: I_0

Z
D
and V
C
_1M
I
C
_2

Z
D
and V
C
_1M
The characteristic and limit angles of the directional comparator are adjustable independently from the mho and reactance
comparators. The directional characteristic improves directional integrity of the distance functions.
h) RIGHT BLINDER
The right blinder characteristic is achieved by checking the angle between the following signals:
AB phase element: (I
A
– I
B
)

Z
R
– (V
A
– V
B
) and (I
A
– I
B
)

Z
R
BC phase element: (I
B
– I
C
)

Z
R
– (V
B
– V
C
) and (I
B
– I
C
)

Z
R
CA phase element: (I
C
– I
A
)

Z
R
– (V
C
– V
A
) and (I
C
– I
A
)

Z
R
A ground element: I
A

Z
R
+ I_0

K0

Z
R
+ I
G

K0M

Z
R
– V
A
and I
A

Z
R
+ I_0

K0

Z
R
+ I
G

K0M

Z
R
B ground element: I
B

Z
R
+ I_0

K0

Z
R
+ I
G

K0M

Z
R
– V
B
and I
B

Z
R
+ I_0

K0

Z
R
+ I
G

K0M

Z
R
C ground element: I
C

Z
R
+ I_0

K0

Z
R
+ I
G

K0M

Z
R
– V
C
and I
C

Z
R
+ I_0

K0

Z
R
+ I
G

K0M

Z
R
The blinders apply to the Quad characteristic only.
i) LEFT BLINDER
The left blinder characteristic is achieved by checking the angle between the following signals:
AB phase element: (I
A
– I
B
)

Z
L
– (V
A
– V
B
) and (I
A
– I
B
)

Z
L
BC phase element: (I
B
– I
C
)

Z
L
– (V
B
– V
C
) and (I
B
– I
C
)

Z
L
CA phase element: (I
C
– I
A
)

Z
L
– (V
C
– V
A
) and (I
C
– I
A
)

Z
L
A ground element: I
A

Z
L
+ I_0

K0

Z
L
+ I
G

K0M

Z
L
– V
A
and I
A

Z
L
+ I_0

K0

Z
L
+ I
G

K0M

Z
L
B ground element: I
B

Z
L
+ I_0

K0

Z
L
+ I
G

K0M

Z
L
– V
B
and I
B

Z
L
+ I_0

K0

Z
L
+ I
G

K0M

Z
L
C ground element: I
C

Z
L
+ I_0

K0

Z
L
+ I
G

K0M

Z
L
– V
C
and I
C

Z
L
+ I_0

K0

Z
L
+ I
G

K0M

Z
L
The blinders apply to the Quad characteristic only.