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CT PT Ratio Formula:
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The CT PT Ratio calculation determines the relationship between current transformer secondary current and potential transformer secondary voltage adjustment. This ratio is crucial for power system protection, metering, and relay coordination in electrical engineering applications.
The calculator uses the CT PT ratio formula:
Where:
Explanation: This calculation helps determine the proper scaling factor between current and voltage measurements in power system instrumentation.
Details: Accurate CT PT ratio calculation is essential for proper relay protection settings, accurate energy metering, and ensuring the correct operation of protective devices in electrical power systems.
Tips: Enter CT secondary current in amperes and PT secondary voltage adjustment in volts. Both values must be positive numbers greater than zero for accurate calculation.
Q1: What is the typical range for CT secondary current?
A: Standard CT secondary currents are typically 1A or 5A, but can vary based on specific application requirements.
Q2: What are common PT secondary voltage values?
A: Common PT secondary voltages are 120V, 115V, or 69.3V, depending on the system configuration and standards.
Q3: Why is the ratio unitless?
A: The ratio is unitless because it represents the relationship between two different electrical quantities (current and voltage) in their respective units.
Q4: When is this calculation most important?
A: This calculation is critical during protection system design, relay setting calculations, and when commissioning new electrical equipment.
Q5: Can this ratio be used for transformer sizing?
A: While related, this specific ratio is primarily used for instrumentation and protection purposes rather than transformer physical sizing calculations.