Toshiba GR-200 Series Instruction Manual page 38

Phase difference calculation
|V|•|I|cos(−) 0
Amplitude calculation
|l| OC pickup current
Amplitude calculation
|Vpol| Set voltage (OV-Vpol)
Figure 2.1-3 Direction determination after loss of voltage memory
If a single phase is connected to a heavy load, and the other phases are not connected to
heavy loads, the user can program separately the directional OC element such that OC will
send a trip signal only when the fault current detected is in the same direction among two
phases or more of the three-phases.
A setting and a scheme switch, as well as the non-directional OC element, provide the
settings for the directional OC element: for example, the user can set the threshold value of
the OC at stage 1 with the setting [OC1] and Forward can be set for the scheme switch [OC1-
Dir]. Setting of the sensing angle (θ) is configured by the setting [OC1-Angle] with the value of
θ set in the range of -90 – 90°. Figure 2.1-4 shows an example of an angle and a characteristic
set with θ.
Reverse
Operation zone
Directional characteristic
θ= 0°
angle line
Forward
Operation zone
θ= 0°
Figure 2.1-4 Examples of directional characteristic angle (θ)
&
F/F
1
Forward
Operation zone
Vpol
θ= +60°
Forward
Operation zone
θ= -60°
- 19 -
1
&
1
Forward
Directional characteristic
Operation zone
angle line
θ= +60°
Vpol
Reverse
Operation zone
Reverse
Operation zone
Vpol
θ= -60°
Directional characteristic
Forward
angle line
Operation zone
6F2T0200 (0.15)
Output of
directional element
Directional characteristic
angle line
θ= +90°
Vpol
Reverse
Operation zone
θ= +90°
Reverse
Operation zone
Vpol
θ= -90°
Directional characteristic
angle line
θ= -90°
GRE200 (1,2)