CT(current transformer) rated electric meter

[rickitek]

after calibration my electric meter is still innacurate. the contractor says the current transformer(CT)is incorrect. mine was used for control and not for metering, the reasons its innacurate. is this possible? how many types of CT are in the market? what type is use for electric metering?

 

[LSpark]

Generally metering CTs are more accurate than protection CTs (especialy at the lower values of current) but saturate at much lower currents. I'm responsible for a good few tariff metering circuits (UK based) that range from around 5MVA to 700MVA and most of those use class 0.2s CTs, some of the smaller circuits have class 0.5s. I've seen VTs that have protection and metering ratings but not CTs.

 

[waross]

Well, maybe, yes, many, it depends, possibly not: If you want a reasonable answer then include some pertinent data.
Sizes?, secondary current?, calibration?, burden (rated and actual)?, at what PU of rated load do you see inaccuracy?, What are you using the measurement for?
A measurement class CT should be accurate to around 200% of rated current. A protection class CT may be inaccurate at low current but will not saturate until a much higher current than a metering class CT.
If you are attempting to determine the kW of a load with a significant inductive or capacitive component with voltage and current alone, then Google "Power factor".

Bill
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"Why not the best?"
Jimmy Carter