Toshiba GR 200 Series, Инструкция по эксплуатации

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6F2S1915 (0.46)
GRZ200 (Soft 031 & 032)
- 1089 -
10.2.16
Supervision of current in zero-sequence (I0 error)
The zero-phase-sequence current entering to the input circuit is monitored; it is possible to
provide a high sensitivity to detect the failure using the residual circuit current. Equation
(10.2-2) is represented for the supervision:
1.
|I
a
+ I
b
+ I
c
− I
e
|
3
≥ 0.1 × Max(|I
a
|, |I
b
|, |I
c
|) + k
0
(10.2-2)
where,
I
e
Residual current
Max(|I
a
|, |I
b
|, |I
c
|) The largest amplitude among Ia, Ib and Ic
k
0
: 5% of the rated current†
†Note: The rated current above the equation is defined with the setting of the VCT. For
more information regarding the VCT, see Chapter
Technical description:
Transformer module for AC analog input.
(i)
Error level
Generally, the default error level has been set at level 3 (
Minor error
), but the user can program
the level using setting [
CHK_IZ:LVl
].; then, set
On
for the settings [
CHK_IZ:Sw
]. The time to
detect can be set using [
CHK_IZ:Timer
], which is set for 15 seconds as default. If the error is
cleared, resetting will be performed after the elapse of setting time.
(ii)
Error message
When detecting an error, an error message can be shown on the LCD screen and an LED is lit.
Table 10.2-33 Error messages provided by the supervisor in CHK_IZ
Message and level Meaning of the information
I0 error Detection of flowing the zero-sequence current
Error level Minor error (Level 3)
Table 10.2-34 Detailed information in Hexadecimal in CHK_IZ
Display area Meaning of the detailed information
N/A (No information is displayed)