Overview
The LZZB(J)6-12Q / LZZJB6-12Q is an indoor single-phase epoxy cast-resin current transformer rated for 12kV class systems. It features a solid epoxy resin insulation structure that provides high dielectric strength, mechanical robustness, and moisture resistance suitable for indoor medium-voltage switchgear environments.
Designed for current measurement, energy metering, relay protection, and feeder monitoring, the transformer supports secondary outputs of 5A or 1A with metering accuracy classes of 0.2, 0.2S, 0.5, and 0.5S, as well as protection classes including 5P10, 5P15, 10P10, and 10P15. It is applicable in 10kV, 11kV, and 12kV indoor switchgear installations following proper insulation coordination.
Key Ratings Snapshot
| Parameter | Rating |
|---|---|
| Voltage class | 12kV |
| Insulation level | 12/42/75kV |
| Rated frequency | 50Hz or 60Hz |
| Primary current range | 20A – 1500A |
| Secondary current | 5A or 1A |
| Metering accuracy | 0.2, 0.2S, 0.5, 0.5S |
| Protection class | 5P10, 5P15, 10P10, 10P15 |
| Application | Indoor switchgear, metering panels, feeder cabinets |
Model Designation
- L: Current transformer
- Z: Cast-resin insulation / epoxy casting structure
- ZB / ZZB: Indoor cast-resin current transformer structure series
- J: Enhanced or structural variant reference, depending on manufacturer drawing
- 6: Design sequence code
- 12Q: 12kV class reinforced / compact indoor structure reference
Construction
The transformer features an indoor epoxy cast-resin construction with integrated primary terminals, a secondary terminal block, and a compact base plate for secure mounting in switchgear. The solid resin body ensures excellent insulation performance, mechanical stability, and resistance to environmental factors such as humidity and dust. This design is optimized for fixed installation in medium-voltage indoor applications where space constraints and reliable electrical performance are critical.
Technical Parameters
Service Conditions
- Installation location: indoor medium-voltage switchgear
- Rated voltage: 10kV, 11kV and 12kV class systems by project confirmation
- Rated frequency: 50Hz or 60Hz
- Ambient temperature: -5°C to +40°C for 12Q catalogue reference; -5°C to +55°C for related 10X reference
- Indoor environment: should be free from conductive dust, corrosive gas, explosive medium and abnormal condensation.
- Special environmental conditions: For high humidity, coastal, high altitude or heavy pollution projects, creepage distance and insulation coordination should be confirmed before ordering.
Technical Parameters
The LZZBJ6-12Q / LZZJB6-12Q is an indoor epoxy cast-resin current transformer designed for 12kV class systems (suitable for 10kV, 11kV, and 12kV applications), with an operating ambient temperature range of -5°C to +40°C (or up to +55°C for related 10X variants). It complies with IEC 61869-2 and GB20840.2-2014 standards and supports primary current ratings from 20A to 1500A depending on the model variant.
| Rated Primary Current (A) |
Accuracy Classes Combination |
Rated Output (VA) | Rated Short-Time Thermal Current (kA/1S) |
Rated Dynamic Current (kA) |
||
|---|---|---|---|---|---|---|
| 0.2 | 0.5 | 10P | ||||
| 5~200 | 0.2/0.2 0.2/0.5 0.2/10P 0.5/10P |
10 | 10 | 15 | 80 I1n | 200 I1n |
| 300 | 20 | 50 | ||||
| 400 | 28 | 70 | ||||
| 600 | 40 | 100 | ||||
| 800 | 50 | 125 | ||||
| 1000 | 64 | 160 | ||||
Installation & Wiring
Installation Diagram
This indoor epoxy cast-resin current transformer is designed for secure mounting within switchgear cabinets. Installation must follow the approved outline drawing to ensure correct alignment of mounting holes, primary busbar routing, secondary terminal orientation, and adequate clearance for phase-to-ground, wiring access, and maintenance.
Selection & FAQs
Selection Guide
- Resolve the exact designation—LZZB6-12Q, LZZJB6-12Q or the title’s LZZBJ6 spelling—from the factory nameplate and drawing.
- Select LZZB6 for documented 20A–300A duties or LZZJB6 for the extended 20A–1500A range and reinforced structure.
- Choose 1A or 5A and pair 0.2/0.2S/0.5/0.5S metering with the required 5P10, 5P15, 10P10 or 10P15 protection.
- Calculate each core burden and verify the 10VA–20VA output and ALF for the exact variant and ratio.
- Confirm ratio-specific fault withstand, 12/42/75kV insulation, mounting, primary busbars, secondary access and −5°C to +40°C duty.
Frequently Asked Questions
Q1: Can this 12kV current transformer be applied in 10kV switchgear?
Yes, it is designed for 10kV, 11kV, and 12kV class systems. Ensure the indoor environment is free from corrosive gases. Confirm specific project requirements with the factory before ordering.
Q2: Which accuracy class combination is suitable for protection relays?
Select the appropriate accuracy class combination based on your metering or protection needs. The rated output must match your connected burden per IEC 61869-2 standards. Contact us to confirm the exact combination for your project.
Q3: What are the rated short-time thermal current limits?
Thermal and dynamic current ratings vary by the 20A to 1500A primary model. Verify the specific kA/1s and peak kA values in the technical datasheet. Factory confirmation is required for exact short-circuit coordination.
Q4: How should the indoor installation environment be prepared?
The location must be free from conductive dust, explosive mediums, and abnormal condensation. Ambient temperature should remain between -5°C and +40°C for the 12Q variant. Consult the factory for special environmental adaptations.
Q5: Are these epoxy cast-resin transformers compliant with IEC standards?
Yes, the LZZBJ6-12Q series fully complies with IEC 61869-2 and GB20840.2-2014 standards. It supports 50Hz and 60Hz rated frequencies for global projects. Request the specific type test certificates during the procurement process.
Q6: When should special creepage distances be confirmed before ordering?
Special creepage distances are required for high humidity, coastal, or heavy pollution projects. Insulation coordination must be verified prior to manufacturing the epoxy cast-resin unit. Contact the factory for environmental adaptation details.
Q7: Why choose epoxy cast-resin for indoor medium-voltage switchgear?
Epoxy cast-resin provides excellent insulation and mechanical strength for indoor medium-voltage switchgear. It operates reliably in 10kV to 12kV systems up to +40°C. Consult the manufacturer for specific panel integration details.