ISA T 2000 - CT Tests: Polarity by Impulses

DOC. MIE11110 Rev. 5
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If, when the test START button (56) is pressed, the HV key is
already ON, the following message is displayed:
In this instance, press the STOP button (55), turn OFF the HV key
(28), then press test START button (56).
If, when the test START button (56) is pressed, the adjustment
knob (6) is not at zero, the following message is displayed:
Press the OFF button (55), move the knob and start again.
When you are satisfied with the result, press SAVE: test result is
saved. Return to zero the adjustment knob (6).
During this test, the isolation resistance should typically be more
than 1 MOhm. An higher resistance could mean that there is a
connection error; a lower resistance typically is caused by the
presence of moisture: it is advisable to clean and dry the
transformer, and to repeat the test.
1 .1.8. CT tests : polarity by impulses
When this test is selected, the following menu is displayed.
Purpose of the test is to verify the CT polarity by applying current
impulses to the primary side, and by checking their polarity at the
secondary side. The current impulse applied at the primary side is
a positive edge, followed by a slow RC discharge. The
corresponding impulse at the secondary side will be mainly