7PG2113/4/5/6 Solkor Description of Operation
4.4
Current Protection: High Impedance Restricted Earth
Fault - (64H)
One high impedance Restricted Earth Fault (REF) element is provided
64H-1
.
The relay utilises fundamental current measurement values for this function.
The single phase current input is derived from the residual output of line/neutral CTs connected in parallel. An
external stabilising resistor must be connected in series with this input to ensure that this element provides a high
impedance path.
64H Current Setting
sets the pick-up current level. An output is given after elapse of the
64H Delay
setting.
External components – a series stabilising resistor and a non-linear resistor – are used with this function. See
‘Applications Guide’ for advice in specifying suitable component values.
Operation of the high impedance element can be inhibited from:
Inhibit 64H
A binary or virtual input.
Figure 4.4-1 Logic Diagram: High Impedance REF (64H)
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