Toshiba GR-200 Series Instruction Manual page 89

Relay polarity
2.4.1
The user can choose either non-directional SEF or directional SEF for each SEF stage. In
addition, the user can further select either the forward or the direction for each of the
directional SEF elements selected.
Characteristic of non-directional SEF
(i)
The characteristic of the non-directional type SEF function is a circle at the origin. A setting
and a scheme switch is used to configure each non-directional SEF element; i.e., the user can
set the threshold value of the non-directional SEF element for stage1 using setting [SEF1].
NonDir should be set for the scheme switch [SEF1-Dir].
Characteristic of directional-SEF in the forward direction
(ii)
As shown in Figure 2.4-1, the characteristic of the directional-SEF elements in the forward
direction is a semi-circle based upon the borderline; the hatched area shows the operating
region of the directional-SEF element.
Residual
current (Ie)
Forward
Operation zone
Figure 2.4-1 Characteristic of the directional-SEF element in the forward direction
Note: Directional characteristic angle (θ) forms the angle between the reference quantity
and the directional characteristic angle line. The operating zone is bordered on
one side by a borderline and is extending in the direction that contains both the
reference (polarizing) and operating quantities. The border-line will have margin
angles (2.5°); thus, the relay direction for the operation will be determined
securely even if the SEF element shall operate in a large current region (that is,
SEF does not issue a trip signal if a large current enters at Ie of VCT terminal,
which can be discussed in Chapter
analog input
A setting and a scheme switch, as well as the non-directional SEF element, provide the
settings for the directional SEF element: for example, the user can set the threshold value
Reverse
Operation zone
2.5°
Margin angle
2.5°
Polarizing voltage (-3V
-θ
φ
Directional characteristic
angle line
→p. 510).
- 70 -
Forward
Operation zone
Residual
2.5°
current (Ie)
2.5°
)
0
Technical description: Transfer module for AC
6F2T0200 (0.15)
Directional characteristic
angle line
φ
+θ
Polarizing voltage (-3V
Reverse
Operation zone
GRE200 (1,2)
)
0