Overview
The LZZBJ9-10LS/150 and LZZBJ9-10LS/150L are indoor epoxy cast-resin slot-type current transformers designed for 10 kV, 11 kV, and 12 kV class medium-voltage switchgear systems. They feature a vertical busbar slot structure where the primary conductor passes through or is fixed within the upper slot area, providing insulation, mechanical support, and secondary signal output in a fully enclosed resin body.
These CTs support secondary currents of 5 A or 1 A with accuracy classes including 0.2S, 0.2, 0.5 for metering and 5P or 10P for protection applications. They are suitable for current measurement, energy metering, relay protection, and switchgear monitoring, complying with standard insulation coordination of 12/42/75 kV and operating at 50 Hz or 60 Hz.
Key Ratings Snapshot
| Parameter | Rating |
|---|---|
| System voltage | 10 kV, 11 kV, 12 kV |
| Insulation level | 12/42/75 kV |
| Rated frequency | 50 Hz / 60 Hz |
| Secondary current | 5 A or 1 A |
| Primary current range | 10 A – 2000 A |
| Metering accuracy | 0.2S, 0.2, 0.5 |
| Protection accuracy | 5P, 10P (e.g., 5P10, 10P20) |
| Installation type | Vertical slot / busbar-through |
| Indoor/outdoor | Indoor |
| Insulation material | Epoxy cast-resin |
| Construction | Fully enclosed, dry-type |
| Application | Switchgear current monitoring, metering, protection |
Construction
The LZZBJ9-10LS/150 series features a robust indoor construction using epoxy cast-resin insulation, forming a fully enclosed, dry-type body that provides high dielectric strength, mechanical stability, and resistance to indoor environmental conditions. The core and secondary windings are completely encapsulated within the resin matrix, ensuring long-term reliability and protection against moisture and contamination. The vertical slot structure is engineered to accommodate the primary busbar either passing through or secured within the upper slot area, integrating electrical insulation and mechanical support into a single compact unit. This design eliminates the need for external insulation barriers in switchgear assemblies and aligns with standard medium-voltage panel layouts requiring busbar-focused current transformer installation.
Technical Parameters
Service Conditions
- Installation location: indoor medium-voltage switchgear
- System voltage: 10 kV, 11 kV and 12 kV class networks
- Rated frequency: 50 Hz / 60 Hz
- Rated secondary current: 5 A or 1 A
- Ambient temperature: -5°C to +40°C for LS/150L sample data; -25°C to +40°C for LS/150 sample data
- Busbar alignment: For slot-type installation, busbar alignment and clearance should be checked before energizing the switchgear.
Technical Parameters
The LZZBJ9-10LS/150(L) is an epoxy cast-resin slot-type current transformer designed for 10–12 kV class systems. It operates within an ambient temperature range of -25°C to +40°C (depending on variant), complies with GB 20840.1-2010, GB 20840.2-2014, and IEC 61869-2:2012 standards, and supports primary current ranges from 10 A up to 2000 A.
| Rated primary current (A) |
Accuracy classed combination |
Rated Output (VA) |
Short-time thermal current |
Rated dynamic current |
||
|---|---|---|---|---|---|---|
| 0.2S | 0.5 | 10(5)P10(15) | ||||
| 10–75 | 0.2S/0.5/10(5)P10(15) | 10 | 15 | 15 | 65×I1n | 2.5×Ith |
| 100–400 | 80×I1n | |||||
| 500–1000 | 80×I1n | |||||
| 1250 | 20 | 20 | 15 | 100 | 250 | |
| 1500 | ||||||
Installation & Wiring
Installation Diagram
The LZZBJ9-10LS/150(L) is installed with a vertical busbar passing through the central slot. The secondary terminal block is located at the lower section of the housing, and the unit is secured to the switchgear base via mounting holes as specified in the approved outline drawing. Proper alignment of the primary conductor within the slot and adherence to dimensional clearances are critical for safe and reliable operation.
Selection & FAQs
Selection Guide
- Choose standard LS/150 or long-body LS/150L from cabinet depth, vertical-slot position, primary contact layout and required current range.
- Select a ratio within 10A–2000A for LS/150 or 10A–1500A for LS/150L based on load, metering range and protection study.
- Specify 1A or 5A and assign each core to 0.2S/0.2/0.5 metering or 5P10/10P10/10P20 protection duty.
- Calculate each circuit burden and verify model-specific VA, thermal current and dynamic current—especially for 1250A–2000A busbar arrangements.
- Approve slot clearance, busbar plate and bolt pattern, P1/P2 orientation, mounting footprint, secondary access, grounding and ambient range.
Frequently Asked Questions
Q1: Can this slot-type CT be installed on 11kV networks?
Yes, subject to project confirmation. The LZZBJ9-10LS is designed for 10kV, 11kV, and 12kV indoor medium-voltage switchgear. Please specify your exact system voltage during inquiry for factory verification.
Q2: Why check busbar alignment before energizing this slot-type CT?
Proper mechanical fit prevents epoxy resin damage during high-current faults. Since this is a slot-type design, busbar alignment and clearance must be strictly verified prior to energization. Contact our engineering team for installation guidelines.
Q3: Which accuracy class combination is available for this model?
It features a 0.2S/0.5/10P multi-ratio accuracy class combination. This supports both precise metering and reliable protection functions within 10-12kV systems. Confirm your specific rated output VA requirements with our sales team.
Q4: How does ambient temperature affect the rated primary current range?
The standard operating range is 10A to 2000A within -25°C to +40°C. For the LS/150L variant, the minimum ambient temperature is restricted to -5°C. Specify your installation environment to ensure correct thermal rating selection.
Q5: Are type test reports available for IEC 61869-2 compliance?
Yes, it complies with IEC 61869-2:2012 alongside GB 20840 standards. These certifications ensure reliable performance for 50Hz and 60Hz rated frequencies. Request the specific type test reports during your procurement process.
Q6: Can the rated secondary current be customized for our panels?
Yes, it supports either 5A or 1A rated secondary currents. Customization is subject to factory confirmation based on your switchgear design. Please provide your panel drawings for technical evaluation.
Q7: Where is this 10kV current transformer typically applied?
It is an indoor slot-type current transformer for 10-12kV medium-voltage switchgear. It is primarily used for current measurement and relay protection in power distribution networks. Contact us for manufacturer-specific application guides.