GE P444 User Manual

Application Notes
P44x/EN AP/Hb
6
MiCOM P40 Agile P442, P444
(AP) 5-
73
Z1 = 4.64 / 79.4° Ω secondary.
Z2 = 100 x 0.484 / 79.4° + 50% x 60 x 0.484 / 79.4°
The Line Angle = 80°.
Therefore actual Zone 1 reach, Z1 = 4.64 / 80° Ω secondary.
3.4.1.6 Zone 2 Phase Reach Settings
Required Zone 2 impedance =
(Green Valley-Blue River) line impedance + 50% (Blue River-Rocky Bay) line impedance
Z2 = (100+30) x 0.484 / 79.4° x 0.12
= 7.56 / 79.4° Ω secondary.
The Line Angle = 80°.
Actual Zone 2 reach setting = 7.56 / 80° Ω secondary
3.4.1.7 Zone 3 Phase Reach Settings
Required Zone 3 forward reach =
(Green Valley-Blue River + Blue River-Rocky Bay) x 1.2
= (100+60) x 1.2 x 0.484 / 79.4° x 0.12
Z3 = 11.15 / 79.4° ohms secondary
Actual Zone 3 forward reach setting = 11.16 / 80° ohms secondary
3.4.1.8 Zone 4 Reverse Settings with no Weak Infeed Logic Selected
Required Zone 4 reverse reach impedance = Typically 10% Zone 1 reach
= 0.1 x 4.64 / 79.4°
Z4 = 0.464 / 79.4°
Actual Zone 4 reverse reach setting = 0.46 / 80° ohms secondary
3.4.1.9 Zone 4 Reverse Settings with Weak Infeed Logic Selected
Where zone 4 is used to provide reverse directional decisions for Blocking or Permissive
Overreach schemes, zone 4 must reach further behind the relay than zone 2 for the remote
relay. This can be achieved by setting: Z4 ≥ ((Remote zone 2 reach) x 120%) minus the
protected line impedance:
Remote Zone 2 reach =
(Blue River-Green Valley) line impedance + 50% (Green Valley-Tiger Bay) line impedance
= (100+40) x 0.484 / 79.4° x 0.12
= 8.13 / 79.4° Ω secondary.
Z4 ≥ ((8.13 / 79.4°) x 120%) - (5.81 / 79.4°)
= 3.95 / 79.4°
Minimum zone 4 reverse reach setting = 3.96 / 80° ohms secondary
3.4.1.10 Residual Compensation for Earth Fault Elements
The residual compensation factor can be applied independently to certain zones if required.
This feature is useful where line impedance characteristics change between sections or
where hybrid circuits are used. In this example, the line impedance characteristics do not
change and as such a common KZ0 factor can be applied to each zone. This is set as a ratio
“kZ0 Res. Comp”, and an angle “kZ0 Angle”:

GE P444 Specifications

General

Brand	GE
Model	P444
Category	Protection Device
Language	English