How do you calculate CT ratio in energy meter?

When analog ammeters are installed, we can easily determine the CT ratio by observing the meter full scale value and then divide that value by 5. Figure 3. Ammeter with a full scale of 150 amps.

How do you calculate CT error ratio?

IP = NS / NP x (IE + IS). IP = 40 x (. 013 + 3.75) = 150.52 A7. To calculate the percentage ratio error,divide the exciting current by the secondary current times 100.

What is CT error ratio?

Explanation: Ratio error of a C.T. is defined as the ratio of the magnitude of the difference between the nominal and actual ratio with respect to the actual ratio. n is the turns ratio.

What is CT burden calculation?

Burden of Cable can be calculated as “Current Square x Resistance of cable per length x 2 times the length of cable” i.e. Cable VA = (2L x R x I^2). Example: If a 250/5A CT is connected to a load of 0.02 ohm resistance through a cable 2-meters long, then the VA burden of Cable will be. Cable VA= 5^2 x 0.02 x 2 x 2=2VA …

How do you read a CT meter?

For example on a 400 Amp supply a CT meter is fitted which is usually rated at 5 Amps. The CT or Current Transformer provides the measuring current to the meter. in above example 400/5 gives a ratio of X 80. On a power bill the meter reading will be given and that will be multiplied by the CT ratio.

How to figure out the correct CT ratio to use for an energy meter?

If the CTs are not clearly visible, then check if there’s a document with the meter’s wiring diagram depicting the CTs and their ratios; 5. If the CT ratios in the meter are set correctly, another possibility may be that the power factor could be as low as 0.1 – although I would tend to doubt it.

How to calculate the CT ratio from voltage ratio?

How to Calculate the CT ratio from voltage ratio: The CT ratio is the inverse of the voltage ratio. If your transformer has a voltage ratio is 1:25 means, the CT ratio would be 25:1. It means if the CT has a primary current of 25 Amps, you get 1 Amp as output. The current will be reduced considerably.

How to calculate a three-phase energy meter reading?

Multiply the reading of the dials by the meter multiplier on a little metal tag on the meter. Three phase watthour meters measure all 3 phases of the circuit. No calculation beyond a multiplier is necessary. What are some good ways to improve English grammar and writing abilities for a non-native speaker?

What is the meter multiplier for CT and PT?

If the CT ratio is 200:5, then the meter multiplier is 40, which is simply 200/5. If a service has both CT’s and PT’s then the two values are multiplied together to give the billing multiplier.