GE P24DM - Application Notes; Setting Guidelines (Directional Element); Figure 39: Directional Angles; Figure 40: *Directional Earth Fault Logic with Negative Sequence Polarisation (Single Stage)

V00749
V2
V2
I2
Figure 39: Directional angles
7.4.2.1 DIRECTIONAL EARTH FAULT LOGIC WITH NPS POLARISATION
V00745
VTS Slow BlockVTS Slow Block
IN1> BlockingIN1> Blocking
VTS Blocks IN>1VTS Blocks IN>1
IN1> V2pol Se tIN1> V2pol Se t
Directional
check
IN1> DIRECTIONALIN1> DIRECTIONAL
&
To EF logicTo EF logic
IN1> I2pol SetIN1> I2pol Set
Note: This diagram shows the logic for IN1 (measured earth fault). The logic for
IN2 (derived earth fault) follows simila r p rinciples.
This diagram does not show all st ages. Ot her stages follow similar principles.
Note: This diagram shows the logic for IN1 (measured earth fault). The logic for
IN2 (derived earth fault) follows simila r p rinciples.
This diagram does not show all st ages. Ot her stages follow similar principles.
IN1>1 Char AngleIN1>1 Char Angle
IN1>1 Trip Ang leIN1>1 Trip Ang le
V2V2
I2I2
Figure 40: *Directional Earth Fault logic with negative sequence polarisation (single stage)
V
oltage Transformer Supervision (VTS) selectively blocks the directional protection or causes it to revert to non-
directional operation. When selected to block the directional protection, VTS blocking is applied to the directional
checking which effectively blocks the Start outputs as well.
7.5 APPLICATION NOTES
7.5.1 SETTING GUIDELINES (DIRECTIONAL ELEMENT)
With directional earth faults, the residual current under fault conditions lies at an angle lagging the polarising
v
oltage. Hence, negative RCA settings are required for DEF applications. This is set in the cell I> Char Angle in the
relevant earth fault menu.
Chapter 6 - Current Protection Functions P24xM
114 P24xM-TM-EN-2.1