In a three-phase system, what does V_L represent?

In a three-phase system, what does V_L represent?

• A. The voltage between a line and neutral
• B. The voltage between any two lines
• C. The phase voltage
• D. The line-to-ground voltage

Answer: (B)

V_L is the line-to-line voltage—the voltage measured between any two lines in a three-phase system. This is the voltage that feeds equipment connected across two phases and is the quantity typically labeled as line voltage. In a balanced system, the line-to-line voltage equals sqrt(3) times the line-to-neutral (phase) voltage, so the phase voltage is V_LN = V_LL / sqrt(3). The line-to-neutral voltage is the voltage from a single line to the neutral conductor, and line-to-ground is the same as line-to-neutral only when the neutral is bonded to ground. So the essential idea is that V_L represents the voltage between two lines.

V_L is the line-to-line voltage—the voltage measured between any two lines in a three-phase system. This is the voltage that feeds equipment connected across two phases and is the quantity typically labeled as line voltage. In a balanced system, the line-to-line voltage equals sqrt(3) times the line-to-neutral (phase) voltage, so the phase voltage is V_LN = V_LL / sqrt(3). The line-to-neutral voltage is the voltage from a single line to the neutral conductor, and line-to-ground is the same as line-to-neutral only when the neutral is bonded to ground. So the essential idea is that V_L represents the voltage between two lines.