what is the differece between measuring CT & Protection CT??
what is the Saturation Point of measuring CT & Protection CT??
Each CT has a B-H curve which is proportional to the core materials. the y axis is voltage and x axis is magnetising current. This curve has linear part, knee part and fixed part. Saturation means, increasing of current results no voltage increasement. in the linear part, increase of current means increase of voltage, coming to knee part, increase of voltage started to reduce and at a point of the curve, it stops.
10 P 20 means that this CT has a %error (see the 60044-1) at the 20*Primary current.
A measuring CT would be used for a watt meter at a service. It would determine the amount of current flowing through the wire. A protecting CT would be used with ground fault protection relays. The three phase wires pass through the donut(CT) and then it detects an imbalance among the phases. For example if there's a fault the CT would sense it and then activate the relay which will then trip the circuit breaker.