Toshiba GR200 Series - 2.28.1 Operation and characteristic; 2.28.2 Scheme logic

6F2S1914 (0.49)
GRL200 (Soft 033 & 037)
- 357 -
2.28.1 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



 



is larger than the setting [ICD-2f], the ICD
function is able to identify the presence of inrush currents. Figure 2.28-1 illustrates the
characteristic; the operation region is designated by the hatched area; the operation threshold
is set with the [ICD-OC].
I
1f
0
I
2f
ICD–OC
θ
ICD-2f (%) = tanθ×100
|I
2f
|/|I
1f
|ICD-2f(%)
|I
1f
|ICD–OC
&
ICD
Figure 2.28-1 ICD characteristic and operation region
As shown in Figure 2.28-1, 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.
2.28.2 Scheme logic
Figure 2.28-2 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 2.28-2 ICD logic