ISF & Accuracy Class Of Current Transformer

You could have asked this question of the equipment supplier when you were discussing solutions to your failed one. Why didn't you do that then?

Prayer?

If what your customer wants is not available, then he has to pay somebody to design it....If he's not willing to do that then they must work with what is available....Your job is to tell them what is available...or design something yourself...

I would say it is possible but you need to talk with CT manufacturers and suppliers for a possible solution and how much of a premium it will cost.

Does the CT ratio have to be low? Perhaps there is another way around the problem.

Interesting question. True, High accuracy and low ISF are seemingly contradicting requirements for a metering class CT. I have seen such CTs in existence but not aware of the design intricacies.

Hope some experts on CT design would care to clarify.

<...Hope some experts on CT design would care to clarify...> Quite. There are plenty of them at the CT equipment manufacturers' facilities, and they are more likely to respond to telephone calls rather than CR4 postings.

Phenomenon: the amount of use of telephones seems inversely proportional to the number of them in existence.

ISF is the ratio of saturation flux density & operating flux density. In low ratio CT say 50/1A , due to low operating flux density the ratio will be high means ISF will be high. Thats' why I have raised my query whether low ISF & HIGH accuracy are possible in low ratio CT or not !

I just wanted to know from a renowned forum like this as design feasibility was my doubt.

I shall go to vendor or for telephonic discussion after this.