Toshiba GR 200 Series, Instruction Manual

Page: 318 / 1563

6F2S1915 (0.46)
GRZ200 (Soft 031 & 032)
- 297 -
2.19.1
Operation and characteristic
The ICD function examines the ratio of a second harmonic current (I2f) to the fundamental
current (I1f) in each phase. If the ratio
|I
2f
| |I
1f
| ⁄
is larger than the setting [
ICD-2f
], the ICD
function is able to identify the presence of inrush currents. Figure 2.19-1 illustrates the
characteristic; the operation region is designated by the hatched area; the operation threshold
is set with the [
ICD-OC
].
I1f
0
I2f
ICD–OC
θ
ICD-2f (%) = tanθ×100
|I2f|/|I1f|  ICD-2f(%)
|I1f|  ICD–OC
& ICD
Figure 2.19-1 ICD characteristic and operation region
As shown in Figure 2.19-1, the user should set both the [
ICD-2f
] and [
ICD-OC
] when the
second harmonic inrush current should be detected. The user should set
On
for the scheme
switch [
ICD-EN
] to enable the ICD operation.
2.19.2
Scheme logic
Figure 2.19-2 illustrates the ICD logic. When second harmonic inrush current is detected, the
ICD signal will be received by other protection functional elements.
8300001C23
8200001C22
8000001C20
8100001C21
ICD
A
B
C
ICD-B
ICD-C
ICD-A
≥1
ICD-OR
To OC, SOTF-OC, STUB-OC
To EF, OCN, BCD
Figure 2.19-2 ICD logic