Overview
The LZZBJ9-10C8/210/2S and LZZBJ9-10C8/210/4S are indoor epoxy cast-resin current transformers designed for 10kV, 11kV, and 12kV medium-voltage switchgear systems. These fully enclosed, support-type devices use epoxy resin insulation to provide stable dielectric performance and robust mechanical support in indoor environments.
They meet IEC standards for measurement, energy metering, relay protection, and automation applications. The 2S version offers dual secondary windings—typically one for metering and one for protection—while the 4S variant supports up to four independent circuits for metering, indication, main protection, and backup protection. Both configurations share the same C8/210 structural platform, ensuring consistent installation across different project requirements.
Key Ratings Snapshot
| Parameter | Rating |
|---|---|
| Voltage class | 10kV, 11kV, 12kV |
| Rated insulation level | 12/42/75kV |
| Rated frequency | 50Hz (60Hz on request) |
| Rated secondary current | 5A or 1A |
| Secondary configurations | 2S (dual), 4S (multi) |
| Primary current range | 5A to 6000A |
| Insulation material | Epoxy cast-resin |
| Accuracy classes | Measurement: 0.2, 0.5; Protection: 5P, 10P |
| Application types | Metering, measurement, protection, backup protection |
| Installation type | Indoor, support-mounted |
| Construction | Fully enclosed, cast-resin insulated |
| Design standard | IEC 61869 |
Model Designation
- L: Current transformer
- Z: Indoor type / support structure
- Z: Epoxy resin casting insulation
- B: Protection level available
- J: Strengthened design
- 9: Design serial number
- 10: 10kV catalogue voltage class (suitable for 10kV, 11kV, 12kV systems with proper insulation coordination)
- C8: Structure / design platform code
- 210: Nominal structure width / installation dimension code
- 2S: Dual-secondary schematic configuration
- 4S: Multi-secondary schematic configuration
Construction
The LZZBJ9-10C8/210 series features a fully enclosed, indoor support-type construction with epoxy cast-resin insulation. The primary conductor, magnetic cores, and secondary windings are completely encapsulated in high-quality epoxy resin, providing excellent electrical insulation, moisture resistance, and mechanical strength for indoor medium-voltage environments. The design ensures clear separation between the high-voltage primary circuit and low-voltage secondary circuits, enhancing operational safety and signal reliability. Primary terminals are configured according to current rating ranges (5A–1000A, 1200A–3150A, and 4000A–6000A), allowing optimized connection layouts for various switchgear busbar arrangements. This robust construction supports long-term stability under continuous load and short-circuit conditions typical in 10kV-class distribution systems.
Technical Parameters
Service Conditions
- Installation location: indoor medium-voltage switchgear
- System voltage: 10kV, 11kV and 12kV class networks
- Rated frequency: 50Hz
- Rated secondary current: 5A or 1A
- Ambient temperature: -5°C to +40°C
- Installation environment: The installation environment should be free from severe vibration, conductive dust, corrosive gas, explosive medium, heavy pollution and abnormal condensation.
- High-current considerations: For high-current applications, temperature rise, busbar connection, ventilation and cabinet clearance shall be reviewed together.
Technical Parameters
The LZZBJ9-10C8/210/2S (4S) is an indoor epoxy cast-resin current transformer designed for 10kV, 11kV, and 12kV class systems. It operates within an ambient temperature range of -5°C to +40°C and complies with GB 20840.2-2014 and IEC 61869-2:2012 standards. The device supports a rated primary current range from 5A to 6000A depending on configuration.
| Rated primary current (A) |
Accuracy classed combination |
Rated Output (VA) |
Short-time thermal current (kA/1s) |
Rated dynamic current (kA) |
||
|---|---|---|---|---|---|---|
| 0.2 | 0.5 | 10p | ||||
| 5~300 | 0.2/0.5 | 20 | 150×I1n | 375×I1n | ||
| 400 | 0.2/10P20 | 20 | 45 | 112.5 | ||
| 500 | 0.5/10P20 | 20 | 45 | 112.5 | ||
| 600 | 0.2/0.5 | 40 | 40 | 80 | 160 | |
| 800 | 0.2/10P25 | 40 | 40 | 80 | 160 | |
| 1000 | 0.5/10P25 | 40 | 40 | 80 | 160 | |
| 1200,1250 | 0.2/0.5 | 40 | 100 | 180 | ||
| 1500,1600 | 0.2/10P30 | 40 | 100 | 180 | ||
| 2000 | 0.5/10P30 | 40 | 180 | 260 | ||
| 2500 | 0.2/10P30 | 40 | 180 | 260 | ||
| 3000,3150 | 0.5/10P30 | 40 | 180 | 260 | ||
| 4000~6000 | 0.5/10P30 | 40 | 180 | 260 | ||
Installation & Wiring
Installation Diagram
The LZZBJ9-10C8/210/2S (4S) current transformer is installed as a support-type unit within indoor switchgear, with primary terminals positioned at the top and secondary terminals located at the base. Mounting is typically achieved via rear or side flanges integrated into the cast-resin body, ensuring secure mechanical fixation and proper alignment with the primary busbar. The installation must accommodate the specific primary terminal layout corresponding to the rated current range (5A–1000A, 1200A–3150A, or 4000A–6000A), as shown in the provided diagrams.
Selection & FAQs
Selection Guide
- Choose 2S for two independent functions or 4S for metering, indication, main protection and backup protection circuits.
- Select the 5A–6000A primary ratio from load and fault studies, then use the correct 5–1000A, 1200–3150A or 4000–6000A terminal layout.
- Define every 1A/5A secondary by purpose, class, ALF and terminal marking; do not infer a four-core assignment from “4S” alone.
- Calculate each circuit burden and verify the exact 10VA–150VA output, thermal current and dynamic current for the selected ratio/configuration.
- Approve the 210-platform footprint, 330mm reference creepage, 58kg support, busbar forces, cabinet ventilation, clearances and shorting blocks.
Frequently Asked Questions
Q1: Can this 10kV CT be installed in 11kV switchgear?
Yes, subject to project confirmation. This epoxy cast-resin transformer supports 10kV, 11kV, and 12kV indoor systems. Specify your exact network voltage for factory verification.
Q2: Which accuracy class combination is available for this model?
The device offers 0.2, 0.5, and 10P accuracy class combinations. Select 0.2 for metering and 10P for protection circuits. Contact us with your specific VA output requirements.
Q3: What are the required installation environment conditions?
Installation must be indoors, free from severe vibration, corrosive gas, and conductive dust. Ambient temperature must remain between -5°C and +40°C. Confirm cabinet ventilation for high-current applications.
Q4: How is the short-circuit thermal capacity rated?
Short-time thermal and dynamic currents are rated according to your selected primary current configuration. Provide your maximum fault current data for accurate sizing. Factory verification is required.
Q5: Which international standards does this current transformer comply with?
It complies with GB 20840.2-2014 and IEC 61869-2:2012 standards. These certifications ensure reliable performance in medium-voltage switchgear. Request the specific type test report during procurement.
Q6: Can the rated primary current be customized up to 6000A?
Yes, the primary current range spans from 5A to 6000A depending on configuration. For high-current customizations, busbar connections and temperature rise must be reviewed. Contact our sales team for details.
Q7: What type of switchgear is this epoxy CT designed for?
It is an indoor medium-voltage current transformer for 10kV to 12kV switchgear applications. The epoxy cast-resin design ensures durability in standard indoor environments. Check with our engineers for specific cabinet clearances.