Instantaneous current for L3 (Three-phase electric application)

Description

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 peak current is Ip for all phases, the instantaneous current (L3) can be calculated as shown.

Related formulas

Variables

IL3instantaneous current in phase (A)
IPpeak current (A)
θtheta (rad)
πpi
ϕphi (dimentionless) (dimensionless)