Overview
The LA-10Q and LAZB-10Q series are epoxy-resin cast current transformers designed for indoor, through-wall installation in 10 kV distribution systems operating at 50 Hz or 60 Hz. These transformers provide galvanic isolation between primary and secondary circuits while delivering a standardized 5 A secondary current proportional to the measured primary current. Their primary conductor can be configured as a single turn, multiple turns, or as a busbar to accommodate diverse switchgear layouts.
Built with high-grade silicon steel cores and fully encapsulated in moisture-resistant epoxy resin, these units ensure reliable performance in environments with high humidity and light pollution, making them ideal for industrial and utility applications requiring accurate metering and robust protection.
Key Ratings Snapshot
| Item | Specification |
|---|---|
| System voltage class | 10 kV, indoor distribution equipment |
| Rated frequency | 50 Hz standard, 60 Hz on request |
| Primary current range | 5 A : 400 A (custom ranges available) |
| Rated secondary current | 5 A |
| Accuracy classes | 0.2/10P10, 0.5/10P10, 10P15 (others on request) |
| Rated burden per core | 10 VA (metering), 15 VA (protection) |
| Insulation level | 12/42/75 kV |
| Partial discharge | < 20 pC (at 1.2 Ur) |
| Thermal current Ith | Up to 30 kA/1 s |
| Dynamic current Idyn | Up to 54 kA |
Model Designation
- L: Current transformer (CT)
- A: Penetrating wall type
- (Z): Cast-resin insulated (optional)
- (B): With protective class (optional)
- -10: Rated voltage: 10 kV
- Q: Intensive insulation type / all-condition insulation type
Construction
The LA-10Q and LAZB-10Q feature a through-wall, support-type structure with fully enclosed epoxy resin casting that integrates the primary conductor, secondary winding, and toroidal magnetic core into a single robust unit. This design delivers superior electrical insulation, excellent moisture resistance, and high mechanical strength. The high-creepage surface and sealed construction make the transformers suitable for operation in humid and lightly polluted indoor environments.
Primary terminals (P1, P2) extend through the wall bushing for busbar or bolted connections, while secondary terminals (S1, S2) are conveniently located at the base for wiring. Polarity is clearly marked to ensure correct installation, and the high-quality silicon steel core minimizes magnetizing losses and enhances measurement accuracy.
Technical Parameters
Service Conditions
- Altitude: <= 1000 m above sea level; higher altitudes require consultation.
- Ambient temperature: -5 deg C to +40 deg C.
- Relative humidity: <= 85 % at 20 deg C.
- Environment: Free from corrosive gases, heavy pollution or chemical contamination.
- Pollution level: Suitable for high humidity and light pollution environments.
- Vibration resistance: Properly mounted units withstand normal shock and vibration experienced in switchgear operation.
Technical Data
| Rated primary current (A) |
Accuracy class combination |
Rated output (VA) |
Thermal current Ith (kA/1 s) |
Dynamic current Idyn (kA) |
|---|---|---|---|---|
| 5:100 | 0.2 / 10P10 or 0.5 / 10P10 | 10 / 15 | 0.5 | 0.8 |
| 10 / 5 | 0.2 / 10P10 | 10 / 15 | 0.9 | 1.6 |
| 20 / 5 | 0.5 / 10P10 | 10 / 15 | 1.8 | 3.2 |
| 50 / 5 | 10P15 | 15 | 4.5 | 8.0 |
| 100 / 5 | 10P15 | 15 | 9.0 | 16.0 |
| 200 / 5 | 10P15 | 15 | 18.0 | 26.0 |
| 400 / 5 | 10P15 | 15 | 30.0 | 54.0 |
Installation & Wiring
Installation Diagram
The LA-10Q and LAZB-10Q current transformers are designed for secure through-wall mounting in indoor switchgear panels. Installation requires alignment with the designated opening in the switchgear wall, followed by bolting using the provided fixing holes. Primary conductors connect via busbar or bolted terminals depending on the selected variant, while secondary wiring is routed from the base terminals to connected instruments or relays.
Outline Dimensions
| Dimension | Value (mm) |
|---|---|
| Total height | 220 |
| Flange width | 180 |
| Wall thickness | 30 |
| Bushing inner diameter (phi) | 35 |
| Mounting hole spacing | 150 x 150 |
| Secondary terminal block size | 40 x 25 |
Selection & FAQs
Selection Guide
- Confirm whether LA-10Q or LAZB-10Q is required. The title omits Q from LAZB while the body includes it; verify the exact enhanced-insulation variant and primary connection on the approved drawing.
- Choose a documented ratio and function. Low-current rows list 0.2/10P10 or 0.5/10P10 measurement/protection combinations, while 50/5A–400/5A rows list 10P15 protection only.
- Do not rely on the corrupted “5:100” entry. Confirm whether it represents a current range or a formatting error, and use an explicit primary/5A ratio on the order and nameplate.
- Check burden and fault duty per version. Use 10VA for applicable measuring cores and 15VA for protection, then verify the listed 1-second thermal and dynamic current against the system study.
- Approve insulation and wall interface details. Confirm 12/42/75kV, partial-discharge limit, humidity/pollution class, 220mm height, 180mm flange, 30mm wall reference, Ø35 aperture, 150 × 150mm holes and terminals.
Frequently Asked Questions
Q1: What environmental limits apply to installing this 10kV current transformer?
Installation is restricted to altitudes up to 1000m and temperatures between -5°C and +40°C. For higher altitudes, consult our engineering team for derating factors.
Q2: Which accuracy class combination is available for metering and protection?
Available combinations include 0.2/10P10, 0.5/10P10, and 10P15. Select 0.2 or 0.5 for metering and 10P for protection. Contact us to specify your exact ratio requirements.
Q3: How does the thermal current rating scale with primary current?
Thermal current capacity scales directly with the primary rating, ranging from 0.5 kA to 9.0 kA. Verify your specific short-circuit duration requirements with our technical support.
Q4: Can the rated output and accuracy classes be customized?
Custom rated outputs of 10 or 15 VA and specific accuracy combinations are available. Please provide your single-line diagram for factory confirmation and exact lead times.
Q5: Do you provide routine test reports before shipment?
Yes, standard routine tests include insulation resistance, power frequency withstand voltage, and accuracy verification. Detailed test certificates are issued upon request. Contact sales for specific documentation needs.
Q6: Where are these wall-mounted epoxy resin current transformers typically applied?
They are designed for indoor 10kV switchgear and power distribution systems in light pollution environments. Ensure the installation area remains free from corrosive gases and chemical contamination.
Q7: Are these LA-10Q transformers suitable for high humidity environments?
Yes, they support high humidity conditions with relative humidity up to 85% at 20°C. Confirm specific environmental parameters and pollution levels with our application engineers before ordering.