Phase Selection Element Uvc - Toshiba GRL100-701B Instruction Manual

The characteristic of the offset directional element is obtained by the following equation.
X + R tanθ ≦ Z
where,
X = reactance component of measured impedance
R = resistance component of measured impedance
θ = directional angle setting (interlinked with directional element angle setting)
Z = offset reach setting (fixed to 1.5Ω in 5A rating and 7.5Ω in 1A rating)
B

2.16.4 Phase Selection Element UVC

The phase selection element has the undervoltage characteristic shown in Figure 2.16.4.1 and is
used to select a faulty phase in case of a single-phase-to-earth fault.
The characteristic is obtained by a combination of the equations below. If equation (1) or equation
(2), or both equations (3) and (4) are established, the UVC operates.
|V| ≤ Vs
|V − IZs| ≤ Vs
−Vs ≤ V sinθ ≤ Vs
0 ≤ V cosθ ≤ |IZs|
X
θ
Z B
Figure 2.16.3.12 Offset Directional Element
B
IZs
V
θ
Vs
Figure 2.16.4.1 Phase Selection Element
(1)
(2)
(3)
(4)
 142 
6 F 2 S 0 8 5 0
R
I