Siemens siprotec SJ62, Руководство пользователя

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2.3 Directional Overcurrent Protection 67, 67N
100
SIPROTEC 4, 7SJ62/63/64 Handbuch
C53000-G1140-C147-A, Edition 07.2015
setting value
1519 ROTATION ANGLE
, positive counter-clockwise. In this case, a ro-
tation of +45
°
.
Figure 2-24 Rotation of the reference voltage, directional phase element
The rotated reference voltage defines the forward and backward area, see Figure 2-
25. The forward area is a range of
±
86
°
around the rotated reference voltage V
ref, rot
.
If the vector of the fault current is in this area, the device detects forward direction. In
the mirrored area, the device detects backward direction. In the intermediate area, the
direction result is undefined.
Figure 2-25 Forward characteristic of the directional function, directional phase element
Direction Determi-
nation of Direction-
al Ground Element
with Ground Values Figure 2-26 shows the treatment of the reference voltage for the directional ground el-
ement, also based on a single-pole ground fault in Phase A. Contrary to the directional
phase elements, which work with the unfaulted voltage as reference voltage, the fault
voltage itself is the reference voltage for the directional ground element. Depending
on the connection of the voltage transformer, this is the voltage 3V
0
(as shown in