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D - 6
Specifying ZCT error adjustment
For the earth fault directional relay connected with ZCT like as CFP1-A01,2 and so on, this ZCT error adjustment function
is applied to improve its composite characteristic through correcting the error of ZCT transformation ratio
ZCT error can be adjusted that its nominal transformation ratio within the range of 200mA/1.5mA ~ 4.1mA ( ± 0 ~
+2.6mA).
For this function the real ZCT transformation ratio needs to be remembered in advance before putting the relay into
service.
Please input 200mA zero phase current into ZCT primary, then remember and adjust the real measured value
of ZCT secondary.
<< Example >>
transformation ratio is 200 : 2.1mA when the relay is connected with ZCT.
Step
Description
1
According to each corresponding instruction
manual to connect ZCT with I
earth fault directional element, then to
achieve the status that is able to input 200mA
zero phase current into ZCT primary.
Start setting mode.
The SETTING/CANCEL indicator LED comes
on and the item number blinks.
2
Mode selection (Setting
Operation
Option)
See the section D - 1 for how to select
mode.
3
Select the item number "905" (ZCT error
adjustment).
At this time, the previous remembered
adjustment value is displayed as ZCT
secondary current value in the item data box.
Example:
200/1.5mA (set at time of shipment)
4
Make sure that the item number "905" is
shown in the box, and press the
SELECT/SET switch. The item data box
will start blinking, instead of the item No. box,
and to start measure the secondary current
value of ZCT connected with relay.
According to differential indication status the
following adjustment value will be
remembered.
(1)When "1.5 ~ 4.1" was displayed
It means that it is in available range of error
correction, and the displayed value can be
remembered.
(2)When item data at "4.1" blinking
Please make sure again about the ZCT
connection and input current.
To change the ZCT secondary current from 1.5mA (set at time of shipment) to 2.1mA that its real
input circuit of
o
Forced
SELECT/SET
Operation
Switch
Press
SETTING/
Once
CANCEL
(Omitted)
(Omitted)
UP
-
Once
33
Indication
Item No.
Item data
5
1
1
S E T T IN G /
U P
C A N C E L
D O W N
S E L E C T /
S E T
IN D ./
IN D I.E N D
S E T .E N D /
T R IP
R E S E T
Item No.
Item data
8
0
0
0
1
Item No.
Item data
9
0
5
1
.
Item No.
Item data
9
0
5
2
.
2.
0
0
0
5
1
JEP0-IL9416
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