The LZZBJ9-10 is an indoor, post-type, fully enclosed current transformer (CT) designed for power systems with a rated frequency of 50Hz or 60Hz and a maximum equipment voltage of 12kV. It is the primary choice for indoor switchgear (such as the KYN28A-12) to provide signals for current measurement, energy metering, and relay protection.
Constructed using advanced vacuum-cast epoxy resin, the LZZBJ9-10 features a reinforced insulation structure that protects against moisture, pollution, and mechanical stress. Its rugged "post-type" design also allows it to serve as a supporting insulator for the main busbar, optimizing space within the switchgear cabinet.
Superior Measurement Accuracy: Available in high-precision classes (Class 0.2, 0.2S, or 0.5), making it suitable for revenue-grade billing and high-sensitivity monitoring.
Reliable Relay Protection: Offered with 10P10 or 10P20 protection classes, ensuring the CT maintains accuracy during massive overcurrent events to trigger protective relays instantly.
High Short-Circuit Strength: Engineered to withstand significant thermal and dynamic stress during grid faults, preventing catastrophic failure of the metering circuit.
Partial Discharge Excellence: Our vacuum-casting process ensures a void-free epoxy block, resulting in extremely low partial discharge (PD) levels. This significantly extends the service life beyond industry standards.
Maintenance-Free Durability: The fully enclosed design is resistant to atmospheric aging and chemical corrosion, requiring only simple external cleaning during routine inspections.
| Parameter | Detailed Specifications |
|---|---|
| Model | LZZBJ9-10 (A, B, C, or S variants) |
| Rated Voltage | 10kV / 11kV / 12kV |
| Rated Primary Current | 20A to 3150A |
| Rated Secondary Current | 5A / 1A |
| Accuracy Class | 0.2 / 0.2S / 0.5 / 10P10 / 10P20 |
| Rated Output (VA) | 10VA, 15VA, 20VA, 30VA |
| Insulation Level | 12 / 42 / 75 kV |
| Rated Frequency | 50Hz / 60Hz |
| Standard Compliance | IEC 61869-2 (formerly IEC 60044-1) |
Medium Voltage Switchgear: The standard current sensing component for KYN28, XGN, and other 10kV–12kV metal-clad cabinets.
Industrial Substations: Reliable current monitoring for heavy manufacturing plants, mining operations, and data centers.
Revenue Metering: Providing high-accuracy current reference for commercial billing meters in utility-to-industrial junctions.
Power Quality Analysis: Sensing harmonics and current fluctuations for advanced power monitoring systems.
Copper Core Excellence: We use 99.9% oxygen-free copper for all windings, ensuring minimal resistance and maximum thermal efficiency.
Custom Ratios & Multi-Ratios: We provide bespoke primary/secondary ratios (e.g., 200/5, 400/5, 1000/5) and multi-ratio CTs to meet specific project load requirements.
Rigorous FAT Testing: Every unit undergoes a Factory Acceptance Test (FAT), including polarity checks, error testing, and power-frequency voltage withstand testing.
Tropicalized Design: Our epoxy formula is stabilized for use in high-humidity and high-temperature environments, ensuring dielectric strength remains stable over decades.
Q: Can I use this CT for both metering and protection simultaneously?
A: Yes. The LZZBJ9-10 can be configured with multiple secondary cores (e.g., one for measurement and one for protection) within the same epoxy body.
Q: What is the difference between Class 0.2 and 0.2S?
A: Class 0.2S is a "Special" accuracy class that maintains its precision even at very low loads (as low as 1% of rated current), whereas standard Class 0.2 is rated for loads between 20% and 120%.
Q: How do I select the right Burden (VA)?
A: Calculate the total resistance of your secondary circuit, including cables and the internal impedance of the meters/relays. Selecting a CT with a slightly higher VA rating than your total load ensures the CT remains within its accuracy class.