EF Directional Blocking
The tripping direction for EFs may be:
-
Trip Forward
-
Trip Reverse
-
Trip Forward and Reverse (that is non directional)
When EF Directional Blocking is used, one of three methods can be used to determine the direction of an EF.
-
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 47 Directional Blocking EF Polarizing Methods
|
Polarizing Method (Decision) |
Operating Quantity |
Fault Angle |
Angle logged on Trip |
Default Characteristic Angle |
|---|---|---|---|---|
|
VZPS |
Earth Current Ir (IZPSx3) |
VZPS → IZPS |
VZPS → IZPS |
135° Configurable |
|
Wattmetric |
Residual Power (VZPSx3) x (IZPSx3) x Cos (FA) |
VZPS → IZPS |
(VZPS → IZPS) – CA (180°) |
180° Fixed |
|
Ir Cos (Ø) |
Active Earth Current (IZPSx3) x Cos (FA) |
VZPS → IZPS |
-VZPS → IZPS – CA (180°) |
180° Fixed |