What Loop Is Faulty?; Power Swing Detection And Blocking Logic - GE MiCOM P40 Agile Technical Manual

P44x/EN AP/Hb6
(AP) 5-90
4.1.6

What loop is faulty?

The delta quantity calculated by delta exaggerated algorithm is used to determine which loop
is chosen.
The identified faulty loop will lead to a trip in case of the power swing blocking is unblocked.
This step is a way to accelerate the determination of the faulty loop an, therefore, a trip.
Note:
Regarding the presence of negative sequence current or residual current the exaggerated
delta current detection are calculated on the phase to phase loop or phase to ground loop.
On what phase(s) is there the fault?
Input : I_AB, I_BC, I_CA (rms values)
I_AB = IB – IA
If I_AB > ( 3 × 0.6 × In) then a 'CN Fault is detected.
If I_BC > ( 3 × 0.6 × In) then a 'AN Fault is detected.
If I_CA > ( 3 × 0.6 × In) then a 'BN Fault is detected.
Caution:
4.1.6.1

Power Swing detection and blocking logic

The next figure summarizes power swing logic (detection and blocking):
Even if Delta I status is disabled, exaggerated delta current is always internally
calculated.
During a Power Swing, all Directional elements are disabled (it is not
possible to determine fault direction during a Power Swing).
Application Notes
MiCOM P40 Agile P442, P444