1. What is CT Ratio?

The CT (Current Transformer) Ratio is the ratio of primary current to secondary current, but can also be determined from the voltage ratio when the burden impedance is known. It's a crucial parameter in power system measurements and protection.

2. How Does the Calculator Work?

The calculator uses the CT Ratio formula:

Where:

• \( V_{primary} \) — Primary side voltage (volts)
• \( V_{secondary} \) — Secondary side voltage (volts)

Explanation: The CT ratio can be calculated from the voltage ratio when the burden is purely resistive and known.

3. Importance of CT Ratio Calculation

Details: Accurate CT ratio determination is essential for proper metering, protection relaying, and fault current calculations in electrical power systems.

4. Using the Calculator

Tips: Enter both primary and secondary voltages in volts. Both values must be positive numbers greater than zero.

5. Frequently Asked Questions (FAQ)

Q1: Is the voltage ratio the same as the current ratio?
A: Yes, when the burden is purely resistive and known, the voltage ratio equals the current ratio.

Q2: What are typical CT ratios?
A: Common ratios include 100:5, 200:5, 400:5, etc., but many other ratios are used depending on the application.

Q3: When would you use this voltage method?
A: This method is often used during testing or when the primary current isn't directly measurable.

Q4: What affects the accuracy of this calculation?
A: Burden impedance, phase angle differences, and CT saturation can affect accuracy.

Q5: Can this be used for potential transformers (PTs)?
A: No, PTs have their own ratio specifications and different operating principles.