Toshiba GR-200 Series Instruction Manual page 61

Relay polarity
2.2.1
The user can choose either non-directional EF or directional EF for each EF stage. In addition,
the user can further select the forward or the reverse for each of the directional EF elements
selected.
Characteristic of non-directional EF
(i)
The characteristic of the non-directional type EF function is a circle at the origin. A setting and
a scheme switch is used to configure each non-directional EF element; i.e., the user can set the
threshold value of the non-directional EF element for stage1 using setting [EF1-DT], provided
time characteristic is required for define time delay (DT) described in Chapter 2.2.2(i). The
user should set NonDir for the scheme switch [EF1-Dir].
Characteristic of directional-EF in the forward direction
(ii)
As shown in Figure 2.2-1, the characteristic of the directional-EF elements in the forward
direction is a semi-circle based upon the borderline; the hatched area shows the operating
region of the directional-EF element.
Residual
current (3I )
0
Forward
Operation zone
Figure 2.2-1 Characteristic of the directional-EF element in the forward direction
Note: Directional characteristic angle (θ) forms the angle between the reference quantity
and the directional characteristic angle line. The half plane represents the zone of
operation bordered on one side by the borderline and extending in the direction
that contains both the reference (polarizing) and operating quantities.
A setting and a scheme switch, as well as the non-directional EF element, provide the
settings for the directional EF element: for example, the user can set the threshold value (I
for stage 1 with the setting [EF1-DT] and Forward can be set for the scheme switch [EF1-Dir].
Setting of the sensing angle (θ) is configured by the setting [EF1-Angle] with the value of θ set
in the range of -90 – 90°. Figure 2.2-2 shows an example of an angle and a characteristic using
the θ. The operation of the EF element is based upon the following equation.
Reverse
Operation zone
Polarizing voltage (-3V
-θ
φ
Directional characteristic
angle line
- 42 -
Forward
Operation zone
Residual
current (3I )
0
)
0
6F2T0200 (0.15)
Directional characteristic
angle line
φ
+θ
Polarizing voltage (-3V
Reverse
Operation zone
GRE200 (1,2)
)
0
)
EF