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Drop-off and pick-up characteristic
2.13.1
Figure 2.13-1 shows the UV characteristic as hatched area with concentric circles. The pick-
up threshold voltage (PU) is represented the outer circle; the drop-off voltage point (DO) is
represented the dotted circle. The PU voltage of the UV1 element is set using [UV1]. The DO
voltage of the UV1 element is set using [UV1-DPR].
The inner circle shows the area in which the UV function is blocked when the value of
the block voltage is set for [UVBLK]. Setting [TUVBLK] is also provided so that the user can
delay blocking the UV1 and UV2 elements using the setting.
Time characteristic
2.13.2
The UV element has the relationship between an input voltage and an operation time; the
relationship is divided into two time characteristics: (i) the definite time (DT) and (ii) the
inverse definite minimum time (IDMT).
Definite time characteristic (DT)
(i)
Setting pick-up operation
The user is required to set DT for scheme switch [UV1-Timer] when the UV1 element should
operate in the DT characteristic. The UV1 element has a delay timer for the pick-up operation;
the user can set a delay time using setting [TUV1]. The user can find the delay timer in the UV
function logic. (See Chapter 2.13.4)
Setting drop-off operation
Resetting the UV1 element is performed instantly when a voltage exceeds over the drop-off
voltage.
Inverse definite minimum time (IDMT) characteristic
(ii)
To operate the IDMT characteristic in the UV1 element, set scheme switch [UV1-Timer] IDMT.
Pickup
Figure 2.13-1 UV1 element characteristic
- 143 -
Drop-off
V
V
o
UV block
6F2T0207 (0.01)
GRE200 (5,6)
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