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10.2.18 Supervision of voltage in negative-sequence (V2 error)
Negative-sequence voltage is calculated regularly using three-phase voltages. If Equation
(10.2-3) is satisfied over 10 seconds, the supervision function determines that a failure occurs
on input circuits.
The voltage in negative sequence can be used to detect a failure on the voltage input
circuit with high sensitivity. It facilitates the detection of the incorrect phase sequence if cables
are not connected correctly.
1.
where,
a = Phase shift operator (120)
Error level
(i)
Error level has been set at level 3 (Minor error; default), but the user can change it with setting
[CHK_V2:LVl]. Remember that the user needs to set On for setting [CHK_V2:Sw]. The time to
detect can be changed with [CHK_V2:Timer]; the default time is 15 seconds. After the error is
solved, resetting the error will be performed after the elapse of the setting time.
Error message
(ii)
When detecting an error, the error message will be shown on the LCD screen. LED will be lit
up.
Table 10.2-35 Error messages provided by the supervisor in CHK_V2
Message and level
V2 error
Error level
Table 10.2-36 Detailed information in Hexadecimal in CHK_V2
Display
area
Top
00000001: V2 error is existing
row
Middle
(No information is displayed)
row
Bottom
(No information is displayed)
row
2
| V
+ ��
V
+ aV
a
b
3
Detection of the negative-sequence voltage
Minor error (Level 3)
Meaning of the detailed information
Left column
- 819 -
|
c
≥ 6.35(V)
Meaning of the information
(No information is displayed)
(No information is displayed)
(No information is displayed)
6F2T0207 (0.01)
(10.2-3)
Right column
GRE200 (5,6)
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