About CT Metering

 CT metering, also known as current transformer metering, is a method used to measure electric current flowing through a circuit. It involves the use of current transformers (CTs) to step down high currents to a measurable level that can be accurately measured by the metering equipment.

Here's how CT metering typically works:

1. Current Transformers (CTs): Current transformers are devices that are placed around the conductor carrying the electrical current. They are designed to step down the current flowing through the conductor to a proportional lower value. CTs consist of a primary winding (through which the high current flows) and a secondary winding (through which the stepped-down current flows).
2. CT Ratio: Each CT has a specific CT ratio, which determines the relationship between the primary current and the secondary current. For example, a CT with a ratio of 100:5 means that for every 100 amps of current flowing through the primary winding, 5 amps will flow through the secondary winding.
3. Metering Equipment: The secondary winding of the CT is connected to the metering equipment, such as an electric meter or a data acquisition system. The metering equipment is calibrated to accurately measure the secondary current and convert it into meaningful measurements, such as kilowatt-hours (kWh) for energy consumption or amperes (A) for current flow.
4. Accuracy and Calibration: CT metering systems need to be properly calibrated to ensure accurate measurements. The CT ratio and other parameters may be adjusted during the installation and calibration process to account for any errors and provide precise measurements.

CT metering is commonly used in various applications, including residential, commercial, and industrial settings. It allows for the measurement of high currents safely and accurately, providing essential data for energy management, billing, and monitoring purposes.

CTs should be tested to prove there accuracy.