In the formula for power in a three-phase system, what does 'EL' represent?

In a three-phase system, 'EL' represents the line voltage, which is the voltage measured between any two of the three phase conductors. This is an important concept in alternating current (AC) power systems because the line voltage is used when calculating total system power and for the operation of three-phase motors.

Each of the three phases can have its own voltage level known as phase voltage, which is measured across one phase and neutral in a star (or wye) configuration; however, the line voltage is always greater than the phase voltage in a three-phase system. For example, in a star connection, the relationship between line and phase voltages is given by the formula: Line voltage = √3 × Phase voltage. Understanding this relationship is crucial for electric utility operations and for engineers working on power systems to ensure proper design and troubleshooting of electrical installations.

The remaining options, such as phase voltage, current, and resistance, represent other quantities but do not specifically denote 'EL' in this context. Therefore, recognizing line voltage as 'EL' is foundational for grasping the overall operation of three-phase electrical systems.