1. What is Resistance Overhead AC?

Resistance Overhead AC is defined as the property of the wire or line that opposes the flow of current through it in a three-phase three-wire overhead system. It is a fundamental parameter in electrical engineering that affects power transmission efficiency.

2. How Does the Calculator Work?

The calculator uses the resistance formula:

Where:

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

Explanation: The resistance is directly proportional to the resistivity and length of the wire, and inversely proportional to the cross-sectional area of the wire.

3. Importance of Resistance Calculation

Details: Accurate resistance calculation is crucial for determining power losses, voltage drop, and overall efficiency in electrical transmission systems. It helps in proper system design and material selection.

4. Using the Calculator

Tips: Enter resistivity in Ω·m, length in meters, and area in square meters. All values must be positive numbers greater than zero.

5. Frequently Asked Questions (FAQ)

Q1: What factors affect wire resistance?
A: Resistance is affected by the material's resistivity, wire length, cross-sectional area, and temperature.

Q2: Why is resistance important in power transmission?
A: Higher resistance leads to greater power losses (I²R losses) and voltage drops in the system.

Q3: How does temperature affect resistance?
A: For most conductors, resistance increases with temperature due to increased atomic vibrations.

Q4: What are typical resistivity values for common conductors?
A: Copper: 1.68×10⁻⁸ Ω·m, Aluminum: 2.82×10⁻⁸ Ω·m, Silver: 1.59×10⁻⁸ Ω·m

Q5: How can resistance be reduced in transmission lines?
A: By using materials with lower resistivity, increasing conductor cross-sectional area, or using parallel conductors.