CURRENT TRANSFORMER TESTING


What is CT?

CT means Current Transformer. A CT is a type of instrument Transformer that is used AC(alternating current). It produces a current in its secondary is proportional to the primary current(under normal conditions of operation) and differs from it by an angle that is approximately zero. CT are used for protection, measurement and control in high voltage electrical substations and the electrical grid.





CT Testing Formula: 


Calculation Formula: 


  1. Phase(A) =  CT(A) * CT (Ratio)
  2. CT(A) = Phase(A)/CT (Ratio)




    Example:


    Let this CT rating are 100/5.
    so, CT ratio = 20.
    Now Check Ampere in CT(S1) by Clam Meter.
    If, CT(S1)=5

    So, Phase (A) = CT(A) * CT (Ratio) = 5*20 =100.

    Now you check in Phase(A) by clam meter
    If, Phase(A)= 100
    so , CT is OK.