Bus Bar Angle Through CT

[cabletray]

Will a window CT operate at rated accuracy when the current-carrying bus bar passes thru the window at a 45 degree angle?

 

[cabletray]

Answering my own question, I would say no because if the bus bar current is broken down into vectors, one current component is perpendicular to the plane of the CT and has no effect.

 

[cabletray]

I should have written "parallel" to the plane of the CT and has no effect.

 

[scottf]

it really depends on the current level and the chance for local saturation. In most cases, having the primary conductor not centered in the window has little effect.

I'm not sure I understand/agree with your statement on breaking the primary current into "vectors". Do you mean mechanical vectors or something along that line or are you referring to the magnetic field lines? Either way, the line of thinking that the magnetic field lines must be perpendicular or parallel to the plane of the CT (and I'm not sure how you define plane) is flawed.

 

[rcw retired EE]

A window CT will register all of the current going through the window unless high current saturates the CT. With a cable or bus perfectly centered in the round window, all parts of the CT core are equidistant from the current conductor. With an angled conductor, parts of the core are closer and could become saturated more quickly than other portions during high currents. So, yes there is an effect but it is probably within the accuracy range of the CT.

The CT with angled bus will probably read very close to the ideal current.

 

[PowerfulStuff]

Hmm, an interesting one. I'd propose the opposite, but not out of certainty. In my simple thinking it has to work OK as the enclosed current does not change. As far as saturation is concerned, isn't saturation mainly related to the secondary circuit as the primary circuit has a significant airgap to the core?