SEF Directional Protection
When SEF Directional Protection is enabled, it can use one of three methods to determine the direction of a SEF.
-
VZPS
-
Wattmetric
-
Ir Cos (Ø)
VZPS is the default option. The Decision setting determines the method used. Operating Quantities, Fault Angles and default Characteristic Angles for each method are shown in the table below.
Table 52 Directional Protection SEF Polarising Methods
|
Polarising Method (Decision) |
Operating Quantity |
Fault Angle |
Angle logged on Trip |
Default Characteristic Angle |
|---|---|---|---|---|
|
VZPS |
Earth Current (Ir) |
VZPS → IZPS |
VZPS → IZPS |
VZPS → IZPS |
|
Wattmetric |
Residual Power VZPS x IZPS x Cos (FA) |
VZPS → IZPS |
VZPS → IZPS |
VZPS → IZPS |
|
Ir Cos (Ø) |
Active Earth Current IZPS x Cos (FA) |
VZPS → IZPS |
VZPS → IZPS |
VZPS → IZPS |