Home
Back
Line to Ground Voltage Formula:
| From: | To: |
Line to ground voltage (V_lg) is the voltage measured between any one phase conductor and ground in a three-phase electrical system. It's a fundamental measurement in power systems analysis and safety calculations.
The calculator uses the line to ground voltage formula:
Where:
Explanation: In a balanced three-phase system, the line to ground voltage is equal to the line to line voltage divided by the square root of 3.
Details: Accurate calculation of line to ground voltage is essential for electrical system design, insulation coordination, protective device setting, and safety analysis in power systems.
Tips: Enter the line to line voltage in volts. The value must be positive and greater than zero for accurate calculation.
Q1: When is this calculation applicable?
A: This calculation applies to balanced three-phase systems with sinusoidal waveforms, which is the standard case for most power systems.
Q2: What's the difference between line to line and line to ground voltage?
A: Line to line voltage is measured between two phase conductors, while line to ground voltage is measured between a phase conductor and the ground reference.
Q3: Does this relationship hold for all three-phase systems?
A: This specific relationship (V_lg = V_ll/√3) holds true for balanced three-phase systems. For unbalanced systems, the calculation becomes more complex.
Q4: Why is the square root of 3 used in this calculation?
A: The √3 factor comes from the trigonometric relationship between the phase voltages in a balanced three-phase system, where voltages are 120 degrees apart.
Q5: What are typical values for line to ground voltages?
A: Common values include 120V (for 208V systems), 277V (for 480V systems), and 7.2kV (for 12.47kV systems), among many others.