1MAC309294-MB F Section 4
Protection functions
RER620 155
Technical Manual
magnitude, the FAULT_DIR and DIRECTION outputs are set to 0 = unknown, except
when the Allow non dir setting is “True”. In that case, the function is allowed to operate in
the directional mode as non-directional, since the directional information is invalid.
The calculated I
0
sin(φ) or I
0
cos(φ) current used in direction determination can be read
through the I_OPER monitored data. The value can be passed directly to a decisive
element, which provides the final pickup and trip signals.
The following examples show the characteristics of the different operation criteria:
Example 1.
I
0
sin(φ) criterion selected, forward-type fault
=> FAULT_DIR = 1
Figure 66: Operating characteristic I
0
sin(φ) in forward fault
The operating sector is limited by Angle correction, that is, the operating sector is 180
degrees - 2*(Angle correction).
Example 2.
I
0
sin(φ) criterion selected, reverse-type fault
The I_OPER monitored data gives an absolute value of the calculated
current. Otherwise, the value of a current in a reverse area is negative.
RCA
= -90 deg
Correction
angle
Min operating
current
0
0
0
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