Metering Current Transformer (CT)

1. Safety Enhancement

Electrical Isolation: CTs physically separate high-voltage/current primary circuits from low-voltage metering equipment, protecting personnel and devices from hazardous voltages.

Prevents Overload: By reducing primary current (e.g., 300A→5A), CTs prevent damage to sensitive meters.

2. Accurate Energy Measurement

Proportional Scaling: CTs maintain precise current ratios (e.g., 300:5) to ensure billing-grade accuracy (e.g., Class 0.5S per IEC 61869-2).

Harmonics Handling: Advanced CTs accurately measure distorted currents (e.g., from inverters/EV chargers).

3. System Flexibility

Wide Current Range: Enable standard meters (5A rated) to measure currents from tens to thousands of amps.

Retrofit Compatibility: Allow meter upgrades without modifying primary conductors.

4. Compliance & Standards

International Certifications: CTs must meet IEC 61869, ANSI C57.13, or MID (for EU billing).

Legal Metrology: Certified CTs are mandatory for utility billing to avoid revenue disputes.

5. Your Use Case (300A Inverter/Battery Bank)

Problem Solved: A 300:5 CT eliminates meter burnout by handling peak charging currents (250–300A).

Installation Note: Always short-circuit CT secondaries when disconnected to avoid high-voltage hazards.

Wuxi Zhongyi Smart Technology Co., Ltd. focuses on the development and manufacturing of smart water meters, energy meters, gas meters, covering more than 90 countries around the world. If you are interested in smart energy meters, please contact Zhongyi Smart!