What is the calculation of current transfer ( C.T ) connect for energy meter?

Question

What is the calculation of current transfer ( C.T ) connect for energy meter?

Answer 1

You must first know the power.for single phase P=VxI ,for three phase P=sqr 3 x V x I x Cos.P is power,V is voltage, I is current. Power  unit is Watt ,Voltage unit is volt ,Current unit is ampers.You have to calculate the current from these formullas.In three phase formulla the Cos is  between 0,92 - 0,98.The current value that you found is the primary current for the transformer.As a standart the secondary value is 5 amps.The current transformers are named as ..?.../ 5 A.For metering you have to use class:0,5 current tr.Current transformers are used both at low and high voltage metering and protection.They are both different.You did not mesioned about the voltage range therefore I don't have any comment about it.