Toshiba GR 200 Series, Инструкция по эксплуатации

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6F2S1915 (0.46)
GRZ200 (Soft 031 & 032)
- 418 -
2.27.5
Detection of current change (OCD)
(i)
Current change detection relay
Suppose that the difference exists between the latest current vector (I
M
) and the last current
vector (I
N
). The OCD function will operate if the difference is larger than the setting. The I
N
is
measured for the last two-cycles; the difference is decided using Equation (2.27-1):
|𝐼
𝑀
− 𝐼
𝑁
| > 𝐼
𝑠
(2.27-1)
where a criteria for the decision is given by the pick-up threshold value (Is).
The pick-up threshold is defined using setting [
OCD
], which is from 0.05 A to 0.20 A at 1 A
rating†. At 5 A rating, 0.25 A to 1.00 A is applied.
I
M
I
N
I
S
Figure 2.27-4 Current change detection
(ii)
OCD logic
Figure 2.27-5 shows the OCD logic and its output signals.
8000001B66
OCD
A
B
C
8100001B67
8200001B68
To VTF
OCD-B
0 t
0.1s
0 t
0 t
8000001B6F
8100001B70
8200001B71
OCD-A
OCD-C
To Common of DISCAR, DEFCAR
Figure 2.27-5 Scheme logic for current change check
(2.84.4)