Overview
The LZZBJ9-12D1 / LZZBJ9-12D2 is an indoor epoxy cast-resin current transformer designed for 11kV and 12kV class medium-voltage switchgear. It features a compact D-type enclosed body with top primary terminals and a lower secondary terminal block, providing robust insulation and mechanical stability for indoor applications.
This CT supports metering accuracy classes such as 0.2S and 0.5S, along with protection class 5P20, making it suitable for current measurement, energy metering, feeder monitoring, and relay protection in AC power systems. It complies with IEC and GB standards and operates at 50Hz (60Hz available upon request), with secondary outputs of 1A or 5A.
Key Ratings Snapshot
| Parameter | Rating |
|---|---|
| Voltage class | 11kV / 12kV |
| Rated insulation level | 12/42/75kV |
| Rated frequency | 50Hz (60Hz optional) |
| Rated primary current | 50A – 2000A |
| Rated secondary current | 1A or 5A |
| Metering accuracy | 0.2S, 0.5S |
| Protection class | 5P20 |
| Secondary winding groups | 1S, 2S, 3S, 4S (configurable) |
| Typical combinations | 0.2(S)/5P20, 0.5(S)/5P20, 0.2(S)/0.5(S)/5P20/5P20 |
| Application | Indoor switchgear, metering cabinets, feeder panels |
| Insulation material | Epoxy cast-resin |
| Structure type | Enclosed indoor D-type |
Model Designation
- L: Current transformer
- Z: Indoor type / cast-resin insulated structure reference
- ZB: Epoxy cast-resin current transformer series
- J: Reinforced or structural design reference
- 9: Design sequence / product platform
- 12: 12kV voltage class
- D1 / D2: D-type mechanical or secondary-winding configuration variants for 12kV indoor applications
Construction
The LZZBJ9-12D1 / D2 features an indoor enclosed epoxy cast-resin structure, ensuring high dielectric strength, moisture resistance, and mechanical durability. The primary conductor path passes through the center of the core, with top-mounted primary terminals for secure connection. Secondary windings are housed within the cast-resin body and terminated at a lower terminal block, allowing clear separation of metering and protection circuits. The compact rectangular design accommodates multi-secondary configurations while maintaining a small footprint suitable for modern switchgear layouts. All internal components are fully encapsulated in epoxy resin, providing reliable performance under normal indoor operating conditions.
Technical Parameters
Service Conditions
- Installation location: indoor medium-voltage switchgear
- Rated voltage: 11kV and 12kV class systems
- Rated frequency: 50Hz; 60Hz by agreement
- Ambient temperature: -5°C to +40°C
- Indoor environment: should be free from conductive dust, corrosive gas, explosive medium, heavy pollution and abnormal condensation.
- Special site conditions: For high humidity, coastal, high altitude or heavy-pollution sites, insulation coordination and creepage distance should be confirmed before ordering.
Technical Parameters
The LZZBJ9-12D1/D2 is an indoor epoxy cast-resin current transformer designed for 11kV and 12kV class systems. It operates within an ambient temperature range of -5°C to +40°C and complies with IEC 61869-2 and GB20840.2-2014 standards. The device supports primary currents from 50A to 2000A, with secondary outputs of 1A or 5A, and offers multiple accuracy class combinations for metering and protection applications.
| Rated Primary Current (A) |
One-Second Thermal Current Ith/1s (kA Virtual Value) |
Dynamic Current Idyn (kA Peak) |
Accuracy Classes Combination |
Rated Secondary
Output (VA) |
|||
|---|---|---|---|---|---|---|---|
| 1S/2S/3S/4S | 0.2(S) | 0.5S | 0.5 | 5P20 | |||
| 50 | 21 | 52.5 | 0.2(S)/5P20 0.5(S)/5P20 0.2(S)/0.5(S)/5P20/5P20 |
10 | 15 | 20 | |
| 75 | 22 | 55 | |||||
| 100,150 | 40 | 78 | |||||
| 200 | 37.8 | 94.5 | |||||
| 250 | 40 | 100 | |||||
| 300 | 50.4 | 126 | |||||
| 400~630 | 63 | 130 | |||||
| 1500,1600 | 63 | 130 | |||||
| 2000 | 80 | 200 | |||||
Installation & Wiring
Installation Diagram
The LZZBJ9-12D1/D2 current transformer is designed for secure mounting within indoor switchgear. Installation requires precise alignment with the mounting base, adequate clearance for primary busbars, and sufficient access to secondary terminals for wiring and maintenance. Ensure phase-to-ground distances and cabinet layout comply with project specifications before final assembly.
Selection & FAQs
Selection Guide
- Select D1 or D2 from the approved outline, mounting base, primary-terminal interface and required secondary-core grouping.
- Choose one of the listed 50A–2000A ratios from load, metering range and fault study; note the catalogue sequence has gaps.
- Specify 1A or 5A and order 1S–4S cores with explicit 0.2(S), 0.5(S) or 5P20 functions and terminal assignments.
- Verify per-core reference outputs of 10VA, 15VA or 20VA against instrument/relay and lead burden.
- Check ratio-specific 21kA–80kA thermal and 52.5kA–200kA dynamic duty, 12/42/75kV insulation, clearances and grounding.
Frequently Asked Questions
Q1: What applications suit this indoor epoxy cast-resin current transformer?
It is designed for 11kV and 12kV indoor medium-voltage switchgear systems. Ensure the installation environment is free from conductive dust and corrosive gases. Contact us for heavy-pollution site assessments.
Q2: Can this 12kV CT be installed in high humidity or coastal areas?
Standard models require normal indoor conditions without abnormal condensation. For high humidity or coastal sites, insulation coordination and creepage distance must be confirmed before ordering.
Q3: How do I select the correct thermal and dynamic current ratings?
Rated primary currents range from 50A to 2000A with corresponding short-circuit withstand capabilities. Provide your specific one-second thermal and dynamic current requirements for accurate model selection.
Q4: Which accuracy class combinations are available for metering and protection?
Multiple accuracy class combinations are supported for both metering and protection cores. Specify your required secondary output of 1A or 5A and exact class needs during inquiry.
Q5: What international standards does this indoor current transformer comply with?
The LZZBJ9-12D1/D2 complies with IEC 61869-2 and GB20840.2-2014 standards. Request specific type test reports or compliance certificates for your regional project requirements.
Q6: Is 60Hz frequency available for this 11kV current transformer?
The standard rated frequency is 50Hz, but 60Hz configurations are available by agreement. Specify your system frequency and project details when requesting a quotation.
Q7: What defines the LZZBJ9-12D1/D2 product category and manufacturer specifications?
It is categorized as an indoor epoxy cast-resin current transformer for 11kV and 12kV systems. Contact the manufacturer for detailed technical specifications and category catalogs.