Overview
The LZZBJ9-24/195W/4S is a medium-voltage, dry-type current transformer rated for 24 kV systems. It features high-quality epoxy-resin insulation and a compact 195 mm equipment width, making it ideal for indoor switchgear installations where space efficiency and electrical reliability are critical.
Designed for both metering and protection applications, this CT supports accuracy classes of 0.5, 0.2, and 0.2S, with optional special protection classes such as PR, PX, PXR, TPX, TPY, TPZ, or IEEE C-class performance. It complies with IEC 61869 and ANSI/IEEE C57.13 standards, ensuring suitability for international utility, industrial, and grid-side projects requiring precise current measurement and dependable relay coordination.
Key Ratings Snapshot
| Parameter | Rating |
|---|---|
| Voltage Class | 24 kV |
| Insulation Medium | Epoxy resin (dry-type) |
| Primary Current Range | 5–600 A (standard); custom ratios available |
| Secondary Current | 5 A (standard) |
| Metering Accuracy Classes | 0.5 / 0.2 / 0.2S |
| Protection Classes | PR, PX, PXR, TPX, TPY, TPZ, IEEE C100–C800 (by design) |
| Installation Environment | Indoor |
| Winding Material | Full copper |
| Standards Compliance | IEC 61869, IEEE C57.13 |
| Application | Metering, measurement, relay protection |
| Cabinet Compatibility | 800 mm and wider MV switchgear |
| Altitude Rating | Up to 5000 m (with standard corrections) |
Construction
The LZZBJ9-24/195W/4S features a robust cast-resin construction, encapsulating precision magnetic cores and full copper secondary windings in high-quality epoxy resin. This dry-type, oil-free design ensures excellent mechanical strength, low partial discharge, and long-term stability under thermal and electrical stress. The compact 195 mm body width is engineered specifically for integration into 800 mm and wider medium-voltage switchgear cabinets, providing sufficient clearance for primary busbar connections, phase-to-phase spacing, and secondary terminal access. All internal components are vacuum-cast to eliminate voids and enhance dielectric performance, supporting reliable operation in demanding indoor power distribution environments up to 24 kV.
Technical Parameters
Service Conditions
- Standards: GB 20840.2-2014, IEC 61869-2:2012 and special requirements
- Rated Insulation Level: 24/65/125 kV
- Rated Frequency: 50/60 Hz
- Rated Secondary Current: 5 A or 1 A
- Ambient Temperature: -5°C to +40°C
Technical Parameters
The LZZBJ9-24/195W/4S is a dry-type epoxy resin cast current transformer designed for 24 kV systems, suitable for indoor switchgear applications. It features full copper windings, supports primary currents from 5–600 A with secondary options of 5 A or 1 A, and complies with accuracy classes up to 0.2S for metering and PR/PX/TPX etc. for protection.
| Rated Primary Current (A) |
Accuracy Classes Combination |
Rated Output (VA) | Rated Short-Time Thermal Current (kA/1s) |
Rated Dynamic Current (kA) |
|||
|---|---|---|---|---|---|---|---|
| 0.2S | 0.2 / 0.5S | 0.5 | 5P | ||||
| 20–40 | 0.2S/0.5 0.2/0.5 0.2/5P10 0.5/5P10 0.2/5P10 0.5/5P10 |
10 | 15 | 15 | 15 | 250 I1n | 625 I1n |
| 50–100 | 300 I1n | 750 I1n | |||||
| 150–250 | 40 | 100 | |||||
| 300–2500 | 15 | 20 | 63 | 160 | |||
| 10–200 | 0.2S/5P20 0.2/5P20 0.5S/5P20 0.5/5P20 0.2S/0.5/5P10 |
10 | 15 | 15 | 15 | 150 I1n | 375 I1n |
| 300–500 | 40 | 100 | |||||
| 600–1000 | 15 | 20 | 20 | 80 | 200 | ||
| 1200–2500 | 0.2S/5P20 0.2/5P20 0.5S/5P20 0.5/5P20 |
20 | 20 | 20 | 30 | 100 | 250 |
Note:
If user’s data go beyond the above-mentioned scopes, they may be subject to an agreement between manufacturer and purchaser.
Installation & Wiring
Selection & FAQs
Selection Guide
- Verify that the switchgear cabinet width is at least 800 mm to accommodate the CT’s 195 mm width and ensure proper busbar layout.
- Select the primary current ratio based on feeder load, protection relay settings, and metering requirements.
- Choose accuracy class 0.2S or 0.2 for high-precision metering applications; use 0.5 for general measurement purposes.
- Specify protection classes such as PR, PX, PXR, TPX, TPY, TPZ, or IEEE C-class only when required by a detailed relay protection study.
- For installations above 1000 m altitude, apply insulation and performance corrections per IEC 61869 and IEEE C57 standards, up to approximately 5000 m.
- Confirm mechanical clearances including phase spacing, busbar hole pattern, terminal cover access, and secondary wiring path before finalizing the design.
Frequently Asked Questions
Q1: Which primary current ratings are available for this 24kV epoxy resin current transformer?
The LZZBJ9-24/195W/4S supports primary currents ranging from 5 A to 600 A. It features full copper windings for optimal thermal performance. Contact our engineering team to specify your exact primary rating.
Q2: What accuracy classes are offered for metering and protection applications?
Metering applications support up to 0.2S class, while protection cores include PR, PX, and TPX classes. This ensures precise measurement and reliable fault detection. Specify your required accuracy class during ordering.
Q3: Can this dry-type current transformer operate in cold indoor environments?
Yes, it is designed for indoor switchgear applications with an ambient temperature range of -5°C to +40°C. The dry-type epoxy resin cast construction ensures reliable indoor performance. Verify your specific site conditions with our technical team.
Q4: How does this model handle short-circuit thermal and dynamic currents?
The transformer is rated for specific short-time thermal and dynamic currents based on your selected primary current. Full copper windings enhance short-circuit withstand capability. Provide your system fault levels for exact parameter confirmation.
Q5: What international standards does this indoor epoxy resin current transformer comply with?
The LZZBJ9-24/195W/4S complies with GB 20840.2-2014 and IEC 61869-2:2012 standards, alongside specific project requirements. Compliance documentation and test certificates are subject to confirmation. Contact our sales team for specific certification details.
Q6: Are custom secondary current options available for our specific switchgear panels?
Yes, the rated secondary current can be configured to either 5 A or 1 A to match your panel requirements. Lead times and specific configurations are subject to factory confirmation. Please submit your inquiry for a tailored quote.
Q7: Where is this 24kV epoxy resin current transformer typically applied?
It is primarily applied in 24 kV indoor switchgear systems operating at 50/60 Hz. The unit features a rated insulation level of 24/65/125 kV for reliable performance. Reach out for detailed manufacturer specifications and application guides.