I want to measure Leakage current in a circuit using current transformer. Im not getting how to do this in ltspice. I have attached a schematic below.
Current through R4 is 5mA.
It should satisfy the equation.
I(L1) = I(L3) + I(R4)

 

I(L1) = I(L3) + I(R4)

I(L1) = I(L3) - I(R4)
I changed the divide to minus. It looks like L1 has the current of R4+R2 while L3 has the current of R2.

It is much better if you include the LTspice file.

ps
Are you working on "Ground Fault Protection"? In that case the transformer(s) are wrong.

 

I(L1) = I(L3) - I(R4)
I changed the divide to minus. It looks like L1 has the current of R4+R2 while L3 has the current of R2.

It is much better if you include the LTspice file.

ps
Are you working on "Ground Fault Protection"? In that case the transformer(s) are wrong.

Sure. Please see the attachment.

 

I(L1) = I(L3) - I(R4)
I changed the divide to minus. It looks like L1 has the current of R4+R2 while L3 has the current of R2.

It is much better if you include the LTspice file.

ps
Are you working on "Ground Fault Protection"? In that case the transformer(s) are wrong.

I(L1) = I(L3) - I(R4). Yes, I think this equation is correct.
Yes I'm working on ground fault protection. And I need a current transformer whose primary is both hot and neutral wire. I want to draw ct in ltspice but I'm not getting to make one. I need help in that.

 

Added a ground on one of the R3 just so I can see it easier. (not needed)
Changed the CT to act correctly. Reversed phasing of L3! Put L1 and L3 on the same core.
When current flows in R1 it passes forward and backward through the CT and cancels out. So the CT does not see it.
When current flows in R2 it appears in L2 and thus R3 (via the turn ratio)
I would make R3, 100 ohms to get more voltage.
I changed the turns ration mostly because I have many 100:1 CT transformers.

 

Added a ground on one of the R3 just so I can see it easier. (not needed)
Changed the CT to act correctly. Reversed phasing of L3! Put L1 and L3 on the same core.
When current flows in R1 it passes forward and backward through the CT and cancels out. So the CT does not see it.
When current flows in R2 it appears in L2 and thus R3 (via the turn ratio)
I would make R3, 100 ohms to get more voltage.
I changed the turns ration mostly because I have many 100:1 CT transformers.
View attachment 316005

I tried doing so and it worked. Just got my output.