Toshiba GR 200 Series, Instruction Manual

Page: 215 / 1563

6F2S1915 (0.46)
GRZ200 (Soft 031 & 032)
- 194 -
2.7.1
Relay polarity
The user can choose either non-directional OCN or directional OCN for each OCN stage. In
addition, the user can further select either the forward or the direction for each of the
directional OCN elements selected.
(i)
Characteristic of a non-directional OCN
The characteristic of the non-directional type (non-directional OCN) is a circle at the origin. A
setting and a scheme switch is used to configure each non-directional OCN element; i.e., the
user can set the threshold value of non-directional OCN element for state 1 using setting
[
OCN1
], provided time characteristic is required for define time delay (DT) described in section
2.7.2(i).
NonDir
is set for the scheme switch [
OCN1-Dir
].
(ii)
Characteristic of directional OCN in the forward
As shown in Figure 2.7-1, the characteristic of the directional-OCN elements in the forward
direction is a semi-circle based upon the border-line; the hatched area shows the operating
region of the directional-OCN.
Figure 2.7-1
Characteristic of the directional-OCN 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 border line 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 OCN element, provide the
settings for the directional OCN element: for example, the user can set the threshold value
Reference voltage or
Polarizing voltage (
−V
2
)
Operation (Trip) zone
I2
Non-operation (No trip) zone
θ
φ