Question

Explain Power measurement by two wattmeter method.

Answer 1

Two Wattmeter Method can be employed to measure the power in a 3 phase, three wire star or delta connected the balanced or unbalanced load. In Two wattmeter method the current coils of the wattmeter are connected with any two lines, say R and Y and the potential coil of each wattmeter is joined on the same line, the third line i.e. B as shown below in figure (A).
The total instantaneous power absorbed by the three loads Z1, Z2 and Z3, are equal to the sum of the powers measured by the Two wattmeters, W1 and W2.

Contents:

Measurement of Power by Two Wattmeter Method in Star ConnectionMeasurement of Power by Two Wattmeter Method in Delta Connection

Measurement of Power by Two Wattmeter Method in Star Connection

Considering the above figure (A) in which Two Wattmeter W1 and W2 are connected, the instantaneous current through the current coil of Wattmeter, W1 is given by the equation shown below.



Instantaneous potential difference across the potential coil of Wattmeter, W1 is given as



Instantaneous power measured by the Wattmeter, W1is

Answer 2

Answer:

Explain any one method of power measurement on the line