Resistivity Using Resistance (Two-Phase Three-Wire OS) Calculator

Formula Used:

\[ \rho = \frac{R \times A \times \sqrt{2}}{L} \]

Resistance Overhead AC (R):

Ohm

Area of Overhead AC Wire (A):

m²

Length of Overhead AC Wire (L):

Resistivity (ρ):

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1. What is Resistivity?

Resistivity is the measure of how strongly a material opposes the flow of current through them. It is a fundamental property that characterizes the electrical conductivity of materials.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ \rho = \frac{R \times A \times \sqrt{2}}{L} \]

Where:

\( \rho \) — Resistivity (Ω·m)
\( R \) — Resistance Overhead AC (Ω)
\( A \) — Area of Overhead AC Wire (m²)
\( L \) — Length of Overhead AC Wire (m)

Explanation: This formula calculates the resistivity of a material based on its resistance, cross-sectional area, and length, with a factor of √2 for two-phase three-wire overhead systems.

3. Importance of Resistivity Calculation

Details: Accurate resistivity calculation is crucial for designing electrical transmission systems, selecting appropriate materials, and ensuring efficient power delivery with minimal losses.

4. Using the Calculator

Tips: Enter resistance in ohms, area in square meters, and length in meters. All values must be positive numbers greater than zero.

5. Frequently Asked Questions (FAQ)

Q1: Why is there a √2 factor in the formula?
A: The √2 factor accounts for the phase relationship in two-phase three-wire overhead systems, where the voltage and current have a 90-degree phase difference.

Q2: What are typical resistivity values for common conductors?
A: Copper has resistivity of about 1.68×10⁻⁸ Ω·m, aluminum about 2.82×10⁻⁸ Ω·m, and silver about 1.59×10⁻⁸ Ω·m at 20°C.

Q3: How does temperature affect resistivity?
A: Resistivity generally increases with temperature for most conductors due to increased atomic vibrations that impede electron flow.

Q4: What are the limitations of this calculation?
A: This calculation assumes uniform material properties, constant temperature, and ideal conductor conditions without considering skin effect or proximity effects.

Q5: How is this different from single-phase calculations?
A: Two-phase systems require the √2 factor to account for the phase difference, while single-phase systems typically use simpler formulas without this factor.