wattmeter problem?

[cabby]

power consumption of a load, estimated at 1500kVA, is to be measured using a 3-phase wattmeter. Load is supplied by 3-phase, 3-wire line, 12kV, line-to-line. Find a suitable wattmeter for the measurement.

This is from "Handbook of Electric Power Calculations" pg 2.5.

Does anyone know how to approach this? the book shows a 120v, 5-A, 3-wire wattmeter as being a good choice.

The book then calculates the line current of 72A and states that a 100:5 ration is chosen for the current transformer. Then the book states that a 100:1 potential transformer is to be used.

I am totally confused. Does anyone have any reference books that cover wattmeter problems?

thanks,

cabby

 

[al***vj]

power consumption of a load, estimated at 1500kVA, is to be measured using a 3-phase wattmeter. Load is supplied by 3-phase, 3-wire line, 12kV, line-to-line. Find a suitable wattmeter for the measurement.

This is from "Handbook of Electric Power Calculations" pg 2.5.

Does anyone know how to approach this? the book shows a 120v, 5-A, 3-wire wattmeter as being a good choice.

The book then calculates the line current of 72A and states that a 100:5 ration is chosen for the current transformer. Then the book states that a 100:1 potential transformer is to be used.

I am totally confused. Does anyone have any reference books that cover wattmeter problems?

thanks,

cabby

Practice, practice, practice. That's the key.