ABB Relion 650 Series Technical Manual page 196

Section 6
Current protection
operate for faults in the forward direction a fault in the reverse direction will give the pickup signal
PUREV. Also if the directional function is set to operate for faults in the reverse direction a fault in
the forward direction will give the pickup signal PUFW.
6.7.7.6 Non-directional ground fault current protection
This function will measure the residual current without checking the phase angle. The function will
be used to detect cross-country faults. This function can serve as alternative or back-up to
distance protection with phase preference logic.
If available the non-directional function is using the calculated residual current, derived as sum of
the phase currents. This will give a better ability to detect cross-country faults with high residual
current, also when dedicated core balance CT for the sensitive ground fault protection will
saturate.
This variant shall have the possibility of choice between definite time delay and inverse time delay.
The inverse time delay shall be according to IEC 60255-3.
For trip, the residual current 3I
When the function is activated binary output signal PUNDIN is activated. If the activation is active
after the set delay
TRNDIN are activated.
6.7.7.7 Residual overvoltage release and protection
The directional function shall be released when the residual voltage gets higher than a set level.
There shall also be a separate trip, with its own definite time delay, from this set voltage level.
For trip, the residual voltage 3V
Trip from this function can be blocked from the binary input BLKVN.
When the function is activated binary output signal PUVN is activated. If the activation is active
after the set delay
total function is shown in figure 101.
190
shall be larger than the set levels (
0
tINNonDir or after the inverse time delay the binary output signals TRIP and
shall be larger than the set levels (
0
tVNNonDir TRIP and TRUN are activated. A simplified logical diagram of the
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1MRK 506 326-UUS B
INNonDirPU ).
UN_PU ).
Line distance protection REL650
Technical manual
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