ABB RET650 Technical Manual page 175

1MRK 504 135-UEN A
Technical manual
Characteristic
for STRV
-RCA +85 deg
RCA -85 deg
Characteristic for forward
release of measuring steps
IEC11000269 V2 EN
Figure 73: Operating characteristic for earth-fault directional element using the
negative sequence components
Two relevant setting parameters for directional supervision element are:
• Directional element will be internally enabled to operate as soon as Iop is bigger
than 40% of I>Dir and directional condition is fulfilled in set direction.
• Relay characteristic angle AngleRCA, which defines the position of forward and
reverse areas in the operating characteristic.
Directional comparison step, built-in within directional supervision element, will set
EF4PTOC function output binary signals:
1. STFW=1 when operating quantity magnitude Iop x cos(φ - AngleRCA) is bigger
than setting parameter I>Dir and directional supervision element detects fault in
forward direction.
2. STRV=1 when operating quantity magnitude Iop x cos(φ - AngleRCA) is bigger
than 60% of setting parameter I>Dir and directional supervision element detects
fault in reverse direction.
Operating area
STRV
0.6 * I>DIR
Characteristic for reverse
release of measuring steps
40% of
I>DIR
RCA
65 deg
I
op
Operating area
Characteristic
for STFW
Section 8
Current protection
-RCA -85 deg
U
I>DIR
STFW
= I
2
IEC11000269-2-en.ai
RCA +85 deg
= -U
pol 2
169