Three phase power measurement using one wattmeter method

AIM:

To measure the 3-phase reactive power by one – wattmeter method for inductive load.

APPARATUS REQUIRED:

THEORY:

Three phase reactive power can be measured by two wattmeter method which is universally adopted Method. The difference between higher reading wattmeter and lower wattmeter reading yields VLILsinΦ. so, the total 3 reactive power is √3 V L I LsinΦ

Reactive power in a balance 3-Φ load can also be calculated by using single wattmeter. In this method, the current coil of the wattmeter is connected in any on line and the pressure coils across the other two lines. Let us assume that the Current coil is connected in R phase and pressure coil is connected across ‘Y’ and ‘B’ phases. 

The total 3-Φ reactive power is, Q = √3 VL IL Sin Φ

PROCEDURE:

• Connect the circuit as shown in fig. 
• Switch ‘ON’ the supply. 
• Note down the corresponding wattmeter reading and calculate 3-Φ reactive power. 
• Now increase the load of three phase Inductive load steps and note down the corresponding meter readings. 
• Remove the load and switch ‘off’ the supply 

CIRCUIT DIAGRAM:

TABULATION:

CALCULATIONS:

RESULT:

Thus the 3-phase reactive power is measured by one – wattmeter method for inductive load.