Expression for apparent power of a balanced 3 phase delta connected system
Answers
Answer:
Since the phase impedances of a balanced star- or delta-connected load contain equal currents, the phase power is one-third of the total power. As a definition, the voltage across the load impedance and the current in the impedance can be used to compute the power per phase.
Let's assume that the angle between the phase voltage and the phase current is θ, which is equal to the angle of the impedance. Considering the load configurations given in the phase power and the total power can be estimated easily.
Per-phase powers in a delta-connected load and a star-connected load.
the total active power is equal to three times the power of one phase.
Power Measurement
In the three-phase power systems, one, two, or three wattmeters can be used to measure the total power. A wattmeter may be considered to be a voltmeter and an ammeter combined in the same box, which has a deflection proportional to VrmsIrms cos θ, where θ is the angle between the voltage and current. Hence, a wattmeter has two voltage and two current terminals, which have + or − polarity signs. Three power measurement methods utilizing the wattmeters are described next, and are applied to the balanced three-phase.