Aided Directional Earth Fault (Def) Protection Schemes ("Aided D.e.f" Menu); Thermal Overload ("Thermal Overload" Menu) - GE MiCOM P40 Agile Technical Manual

Setting
MiCOM P40 Agile P442, P444
2.9

Aided Directional Earth Fault (DEF) protection schemes ("Aided D.E.F" menu)

The relay has aided scheme settings as shown in the following table:
Menu text
GROUP 1 – AIDED D.E.F.
Aided DEF Status
To enable (activate) or disable (turn off) the Directional Earth Fault Element that is used in
an aided scheme.
Polarisation
Setting that defines the method of DEF polarisation. Either zero, or negative sequence
voltage can be taken as the directional reference.
The applications of zero sequence and negative sequence polarisation are described in
chapter P44x/EN AP, section Directional Directional and non directional Earth Fault
Protection).
V> Voltage Set
The V> threshold defines the minimum residual voltage required to enable the aided DEF
directional decision. A residual voltage measured below this setting would block the
directional decision, and so there would be no tripping from the scheme.
IN Forward
Time Delay
Scheme Logic
To select shared, blocking or permissive scheme logic.
Tripping
Tp
Aid Dist Delay (if blocking scheme not shared)
Transmission time in blocking scheme. The Aided distribution time-delay (in the case of a
blocking scheme covering the transmission time) settings will appear in the relay menu.
Further customising of distance schemes can be achieved using the Programmable
Scheme Logic to condition send and receive logic.
IN Rev Factor
'IN Rev Factor' enhances the sensitivity for the residual current in case of reverse fault (for
instance to create a faster blocking logic scheme).
Block. Time Add.
"Block. Time Add." is an additional time-delay, set to extend a pole dead or convergence
detection.
2.10

Thermal overload ("Thermal overload" menu)

The following table shows the menu settings for the thermal protection element:
Menu text
GROUP 1 – THERMAL OVERLOAD
Thermal Char
Thermal characteristic setting. Available choices are: 'Disabled", 'Single' (for line and cable
protection) and 'Dual' (for oil-filled transformers with natural air cooling protection).
Thermal Trip
Sets the full load current (Ι
Default setting
Enabled Disabled, Enabled
Zero Sequence Zero Sequence, Negative Sequence
1 V 0.5 V
0.1 × In 0.05 × In
0 s 0 s
Shared Shared, Blocking, Permissive
Three Phase Three Phase, Single Phase
2 ms 0 ms
0,6 0
0 0
Default setting
Single Disabled, Single, Dual
1Ιn 0.08Ιn
) allowed and the pick-up threshold of the thermal
FLC
P44x/EN ST/Hb6
Setting range
Min Max
20 V
4 × In
10 s
1s
1
10s
Setting range
Min Max
3.2Ιn
(ST) 4-31
Step size
0.01 V
0.01 × In
0.1 s
2 ms
0.1
0.15s
Step size
0.01Ιn