Application Notes; Setting Guidelines (Directional Element); Figure 35: Directional Angles; Figure 36: *Directional Earth Fault Logic With Negative Sequence Polarisation (Single Stage) - GE MiCOM P40 Agile Technical Manual

Chapter 6 - Current Protection Functions
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Figure 35: Directional angles

7.4.2.1 DIRECTIONAL EARTH FAULT LOGIC WITH NPS POLARISATION
IN1 > DIRECTIONAL
IN1> V2 pol Set
IN1> I2pol Set
IN1>1 Char Angle
IN1>1 Trip Angle
VTS Slow Block
IN1> Blocking
VTS Blocks IN>1

Figure 36: *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.
We recommend the following RCA settings:
● Resistance earthed systems: 0°
Distribution systems (solidly earthed): -45°
●
● Transmission systems (solidly earthed): -60°
102
V2
V2
I2
&
I2
Directional
To EF logic
check
Note: This diagram shows the logic for IN 1 (measured earth fault ). The logic for
IN2 (derived earth fault ) follows similar principles.
This diagram does not show all stages . Other stages follow similar principles.
P14D
V2
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P14D-TM-EN-8