Instantaneous power for L3 (Three-phase electric application)
In electrical engineering, three-phase electric power systems have at least three conductors carrying alternating current voltages that are offset in time by one-third of the period. A three-phase system may be arranged in delta (∆) or star (Y) (also denoted as wye in some areas). A wye system allows the use of two different voltages from all three phases, such as a 230/400 V system which provides 230 V between the neutral (centre hub) and any one of the phases, and 400 V across any two phases. A delta system arrangement only provides one voltage magnitude, however it has a greater redundancy as it may continue to operate normally with one of the three supply windings offline, albeit at 57.7% of total capacity. Harmonic current in the neutral may become very large if non-linear loads are connected.
The instantaneous power in a phase, using angle subtraction formula,in L3 is as shown.Related formulas
|PL3||instantaneous power in phase (W)|
|VP||peak voltage (V)|
|IP||peak current (A)|
|ϕ||phi (dimentionless) (dimensionless)|
|θ||phase angle (rad)|