Length Using Line Losses (DC Two-Wire US) Calculator

Formula Used:

\[ Length of Wire DC = \frac{Area of underground dc wire \times Line Losses}{2 \times Resistivity \times (Current underground DC)^2} \]

\[ l = \frac{A \times P_{line}}{2 \times \rho \times (C_1)^2} \]

Area of Underground DC Wire:

m²

Line Losses:

Watt

Resistivity:

Ω·m

Current Underground DC:

Ampere

Length of Wire DC:

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1. What is the Length Using Line Losses Formula?

The Length Using Line Losses formula calculates the length of a DC two-wire underground cable based on its cross-sectional area, line losses, resistivity of the material, and current flowing through it. This calculation is essential for designing efficient electrical distribution systems.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ l = \frac{A \times P_{line}}{2 \times \rho \times (C_1)^2} \]

Where:

\( l \) — Length of Wire DC (meters)
\( A \) — Area of underground dc wire (m²)
\( P_{line} \) — Line Losses (Watt)
\( \rho \) — Resistivity (Ω·m)
\( C_1 \) — Current underground DC (Ampere)

Explanation: The formula calculates the maximum length of wire that can be used while maintaining acceptable power losses, considering the wire's material properties and the current it carries.

3. Importance of Length Calculation

Details: Accurate length calculation is crucial for designing electrical systems with minimal power loss, ensuring efficient energy transmission, and preventing overheating issues in underground DC systems.

4. Using the Calculator

Tips: Enter all values in the appropriate units. Ensure all inputs are positive values. The calculator will compute the maximum allowable length for the given parameters.

5. Frequently Asked Questions (FAQ)

Q1: Why is the formula specific to DC two-wire systems?
A: This formula is designed specifically for direct current (DC) systems with two wires, where the calculation differs from AC systems due to the absence of reactive power and skin effect.

Q2: What is typical resistivity for copper wire?
A: Copper has a resistivity of approximately 1.68 × 10⁻⁸ Ω·m at 20°C. This value may vary slightly with temperature and purity.

Q3: How do line losses affect the calculation?
A: Higher acceptable line losses allow for longer wire lengths, while lower loss requirements restrict the maximum length for a given wire size and current.

Q4: Can this calculator be used for AC systems?
A: No, this formula is specifically for DC systems. AC systems require additional considerations for reactance, power factor, and skin effect.

Q5: What factors affect resistivity?
A: Resistivity depends on the material type, temperature, and sometimes pressure. It increases with temperature for most conductors.