Relationship between phase and line currents
The relationship between phase and line currents depends on the type of circuit being considered.
In a balanced three-phase circuit, the line currents and phase currents are related as follows:
- For a star (or wye) connected system, the line current (IL) is equal to the square root of 3 times the phase current (IPh). Mathematically, IL = √3 * IPh.
- For a delta connected system, the line current (IL) is equal to the phase current (IPh). Mathematically, IL = IPh.
In an unbalanced three-phase circuit, the relationship between phase and line currents can be more complex. The phase currents may have different magnitudes and/or phase angles, resulting in different line currents.
It is important to note that these relationships hold true for sinusoidal steady-state conditions. In transient or non-sinusoidal conditions, the relationships may differ.