Ormazabal ekor.rps - Page 74

IG-150-EN version 04; 03/10/16
74
Protection functions. Description and settings General instructions
ekor.rps
Watimetrical directional
It is use for those lines with compensation via Petersen coil.
In order to allow the directional unit pickup, the following
must be fullled.
1. Exceed a minimum threshold of V
r
2. For forwards faults, the angle between the current and
the voltage, displaced the maximum torque angle, and
must be between 97 and 263
97<ang(I
0
)–angle(V
0
)+characteristic angle<263
3. For backwards faults, the angle between the current
and the voltage, displaced the maximum torque angle,
and must be between 277 and 83
277<ang(I
0
)–angle(V
0
)+characteristic angle<83
4. The power P=V
r
I
ns
cos(j-j
c
) must exceed the minimum
threshold of P in absolute value. If P sign is negative, the
fault is forwards. If it is positive, it will be backwards.
The equation to be done to calculate P is the following one:
P =
(
Re(V) ⋅ cos(φ) + Im(V) ⋅ sin(φ)
)
⋅ Re(I) +
(
Im(V) ⋅ cos(φ) – Re(V) ⋅ sin(φ)
)
⋅
Im(I)
1
Tripping zone
2
Locking zone
Figure 4.14. 4.7.4.1. Watimetrical directional