Protection Engineering Basics and Schemes Protection Engineering | Page 27

 Now take your primary current injector set which can
be operate on 250 ac Voltage , and connect it to any
two primary conductor , we connected it on Red and
yellow phase.
 Now start injecting current, if we injected 10A and
reading on your digital multi-meter is in millimeter,
then this means your polarity is correct. But if reading
on your multi-meter is 20A or more then this means
your polarity is wrong.
1.1.9 Ratio Test:
It is necessary to check ratio before commissioning of any
new CT in circuit. On client
request we can also test
ratio at time of maintenance.
Circuit diagram is given.
pg. 27