Directional Element; Figure 60: Epatr B Characteristic Shown For Tms = 1.0; Figure 61: Types Of Directional Control - GE MiCOM P40 Agile Technical Manual

Chapter 6 - Current Protection Functions
1000
100
10
1
0.1
V00616

Figure 60: EPATR B characteristic shown for TMS = 1.0

11.5

DIRECTIONAL ELEMENT

Where current may flow in either direction, directional control should be used.
A directional element is available for all of the SEF overcurrent stages. This is found in the ISEF>(n) Direction cell for
the relevant stage. It can be set to non-directional, directional forward, or directional reverse.
Directionality is achieved by using different techniques depending on the application. With reference to the figure
below, you can see that directional SEF can be used for:
Solidly earthed systems
●
Unearthed systems (insulated systems)
●
● Compensated systems
Resistance earthed systems
●
The following diagram shows which type of directional control can be used for which systems.
Solidly Earthed Systems
Directional SEF
High Impedance Fault
V00655

Figure 61: Types of directional control

132
1
Current in Primary A (CT Ratio 100A/1A)
Unearthed Systems
(insulated systems)
Directional SEF
Core-balanced INsin(j)
CT characteristic
Directional
Wattmetric
Earth Fault
VN x IN sin (j)
(reactive power)
(HIF)
Core-balanced
EPATR Curve
10
Compensated Systems
(Petersen coil)
Directional SEF
INcos(j)
characteristic
Wattmetric
VN x IN cos (j)
(active power)
CT
100 1000
Resistance-Earthed Systems
Directional SEF
INcos(j)
characteristic
Core-balanced
CT
Directional
Earth Fault
High Impedance Fault
(HIF)
P14xEd1-TM-EN-1
P14x