Comewill, a trusted manufacturer and supplier of electrical measurement and protection devices in China, provides 0.72-40.5kV Indoor Current Transformer (CTs) for industrial, commercial, and utility applications.
0.72-40.5kV Indoor Current Transformer operates based on electromagnetic induction, converting high primary currents into lower, measurable secondary currents to enable accurate metering and protection.
1. Electromagnetic Induction: Alternating current through the primary conductor generates a magnetic field in the iron core, inducing a proportional current in the secondary winding (e.g., 1000:1 ratio).
2. Signal Isolation: Secondary current (typically 5A or 1A) is isolated from the high-voltage primary circuit, ensuring safety for personnel and equipment.
3. Accuracy Control: High magnetic conductivity materials, such as silicon steel sheets or nanocrystalline alloys, minimize hysteresis losses, achieving precision up to 0.2 level (error ±0.2%), in line with IEC 60044-1 standards.
1. Electromagnetic CT
Features: Iron core with winding, cost-effective, highly stable.
Applications: Distribution systems below 10kV, e.g., industrial or commercial electricity metering.
Parameters Example: Rated current ratio 200/5A, load impedance 2.5 Ω (GB/T 20840.2-2014).
2. Electronic CT
Features: Uses Hall elements or fiber optic sensors, wide frequency band (0.1Hz–1MHz), strong EMI resistance.
Applications: New energy power generation, high-speed rail traction systems.
3. Rogowski Coil
Features: Coreless design, high linearity, suitable for transient current measurement.
Parameters Example: Output signal 0.333V/kA, linear error <±0.1% (IEEE C57.13-2016).
Electricity Metering
High-precision industrial or commercial meters, typically requiring 0.5S accuracy (±0.5%), following DL/T 725-2013.
Relay Protection
Overcurrent or differential protection; CTs must meet specific error limits (e.g., 5P20, error ≤5% at 20× rated current).
Industrial Monitoring
High-frequency or high-speed applications (e.g., steel plants, induction furnaces) require electronic CTs with frequency response >10kHz.
Rated Current: Choose 1.2–1.5× the load current for optimal protection.
Accuracy Level: Use 0.2 for measurement CTs; 5P/10P for protection CTs.
Avoid Open Circuit on Secondary: Can generate dangerous kV voltage.
Insulation Check: Regularly check whether the insulation resistance of the 0.72-40.5kV Indoor Current Transformer is ≥1MΩ.
Scenario Matching: Select CT type (electromagnetic, electronic, Rogowski) based on application needs, accuracy, cost, and reliability.
