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

Chapter 6 - Current Protection Functions
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Figure 39: Directional angles

7.4.2.1 DIRECTIONAL EARTH FAULT LOGIC WITH NPS POLARISATION
IN1> DIRECTIONAL IN1> DIRECTIONAL
V2 V2
IN1> V2pol Se t IN1> V2pol Se t
I2 I2
IN1> I2pol Se t IN1> I2pol Se t
IN1>1 Ch ar A ngle IN1>1 Ch ar A ngle
IN1>1 Trip Ang le IN1>1 Trip Ang le
VTS Slow Block VTS Slow Block
IN1> Blo cking IN1> Blo cking
VTS Blocks IN>1 VTS Blocks IN>1

Figure 40: *Directional Earth Fault logic with negative sequence polarisation (single stage)

Voltage 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
voltage. Hence, negative RCA settings are required for DEF applications. This is set in the cell I> Char Angle in the
relevant earth fault menu.
114
V2
Directional
check
&
I2
To EF logic To EF logic
Note: This diagram shows the log ic fo r IN1 (me asure d ea rth fault). The logic for Note: This diagram shows the log ic fo r IN1 (me asure d ea rth fault). The logic for
IN2 (derived earth f ault) follo ws simila r p rinciples. IN2 (derived earth f ault) follo ws simila r p rinciples.
This diagram d oes no t show all st ages. Ot her stages f ollow simila r p rinciples. This diagram d oes no t show all st ages. Ot her stages f ollow simila r p rinciples.
P24xM
V2
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P24xM-TM-EN-2.1