- 303 -
level of the voltage condition. Figure 2.21-2 shows the invers time characteristic of the OV
element when a multiplier setting [OV1-TMS] is used. The OV element uses Equation (2.21-1)
to be in conformity to IEC 60255-127:
where,
t = operating time (seconds),
V = energizing voltage (voltage),
Vs = pickup voltage setting (voltage), and
TMS = time multiplier setting to adjust a curve
If the user will require a user-programmable (original) curve in the inverse time
characteristic, it is provided when the constants of k, a, c are set, as shown in Table 2.21-2. For
example, the user-programmable (original) curve in the OV1 element will be acquired when
Original is set for the scheme switch [OV1-Timer], and when values of respective constants are
set for [OV1-k], [OV1-a], and [OV1-C].
Figure 2.21-2 IDMT characteristic of OV element
0.100
1.000
10.000
100.000
1000.000
1 1.5 2 2.5 3
Operating Time (secs)
Applied Voltage (x Vs)
Overvoltage Inverse Time Curves
TMS = 1
TMS = 2
TMS = 5
TMS = 10
To Next Page
Loading...
