Toshiba GR 200 Series, Instruction Manual

Page: 216 / 1563

6F2S1915 (0.46)
GRZ200 (Soft 031 & 032)
- 195 -
(I
OCN
) for stage 1 with the setting [
OCN1
] and
Forward
can be set for the scheme switch [
OCN1-
Dir
]. Setting of the sensing angle (θ) is configured by the setting [
OCN1-Angle
] with the value
of θ in the range of 0–180°. Figure 2.7-2 shows an example of an angle and a characteristic
using the θ.
The operation decision of OCN uses the following equation:
𝐼
2
≥ 𝐼
𝑂𝐶𝑁
(2.7-1)
𝐼
2
× cos (φ − θ) ≥ 0
(2.7-2)
𝑉
2
≥ 𝑂𝐶𝑁_𝑉𝑝𝑜𝑙
(2.7-3)
where
I2 = Negative phase sequence current
V2 = Negative phase sequence voltage
−V2 = reference voltage (or polarizing voltage)
Φ = lagging angle
θ = OCN setting angle ([
OCN1-Angle
])
IOCN = Setting value of OCN ([
OCN1
] and the others])
OCN_Vpol = Setting value of the polarizing voltage ([
OCN1-Vpol
])
Note: The phase angle in the event of an internal fault is equal to the angle of the zero-
sequence impedance of the system; this value ranges approximately from 50° to
90°. The θ of OCN can be set from 0° to 180°. The minimum voltage necessary to
maintain directionality can be set from 0.5 to 180 V.
Figure 2.7-2
Examples of directional characteristic angle (θ)
Forward
Reverse
Forward
Reverse
Forward
Reverse
Forward
Reverse
Forward Reverse
θ=0° θ=30°
θ=90°
θ=100° θ=170°
θ=30°
θ=90°
θ=100°
θ=170°
Vpol
Vpol
Vpol
Vpol
Vpol
A
ng
le
line