Answer / roy

primary injuction means we will inject the current in the
primary of the current transformer. and according to the CT
ratio and relay setting the relay will operate.
secondary injuction means we will disconnect the wires from
the secondary side of the CT and inject the current to the
relay directly. the relay will operate according to its
threshold.

Answer / yusuff ibrahim sipchem

Primary imnjection test- to test the circults including the primary circuit, i.e the CT by injecting the current to the busbar at low voltage, thew current will be according the busbar system rated current
Secondary injection test-to test the secondary circuit ony, whcih includes the relay and secondary wiring only. CTs can't be tested with this. in this the current will be normally 0-10Amps

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