Toshiba GR 200 Series, Instruction Manual

Page: 275 / 1563

6F2S1915 (0.46)
GRZ200 (Soft 031 & 032)
- 254 -
2.14.1
Drop-off and pickup setting
Figure 2.14-1 shows the characteristic of the OVG element. The outer circle shows the
threshold of pick-up threshold voltage (PU), whereas the inner circle shows drop-off voltage
point (DO). The hatched area shows the operation area of the OVG.
V
V
Pickup
0
Dropoff
Figure 2.14-1 Setting points of OVG
For example, with regard to the OVG1 element, suppose the user sets a pick-up value in
P.U for setting [
OVG1
]. Then the user should set a drop-off value using setting [
OVG1-DPR
],
which configures the ratio of the PU to the DO.
2.14.2
Delay of the operation of the OVG element
The OVG element has a delay timer for the operation. For the OVG1 element, the user can set
a delay time using setting [
TOVG1
]. The user can find the delay timer in the OVG function
logic. (See section 2.14.5)
2.14.3
Time characteristic
The OVG element has two characteristics between a voltage condition and an operation time;
hence, the user should select a mode either (i) definite (independent) time characteristic delay
or (ii) inverse (dependent) time characteristic delay. For the definite time characteristic delay,
the operation time is a constant. In the inverse time characteristic delay, the operation time
depends upon the level of the voltage condition.
(i)
Definite time characteristic (DT)
To operate the definite (independent) time delay, set
DT
for scheme switch [
OVG1-Timer
]
.
Resetting the OVG element is performed when a voltage falls below the drop-off voltage.
(ii)
Invers time delay (IDMT)
To operate the dependent (invers) time delay, set
IDMT
for scheme switch [
OVG1-Timer
].