Overview
The LFDZ2-10 is an indoor wall-through type current transformer with epoxy resin cast insulation, designed for 10kV, 11kV, and 12kV class medium-voltage AC systems at a rated frequency of 50Hz. It features a fully enclosed cast-resin structure that ensures stable insulation performance and mechanical robustness in indoor environments.
This transformer supports accuracy classes suitable for both metering (e.g., 0.5) and protection (e.g., D-class) applications, making it ideal for use in medium-voltage switchgear, distribution cabinets, and indoor power distribution systems. It complies with standard requirements for current measurement, energy metering, and relay or differential protection circuits in industrial and utility installations.
Key Ratings Snapshot
| Parameter | Rating |
|---|---|
| Rated voltage class | 10kV / 11kV / 12kV |
| Rated insulation level | 11.5/42/75kV |
| Rated frequency | 50Hz |
| Rated secondary current | 5A |
| Primary current range | 75A to 400A |
| Accuracy combinations | 0.5/0.5, 0.5/D, D/D |
| Installation orientation | Vertical or horizontal |
| Insulation material | Epoxy resin cast |
| Application types | Measurement, metering, relay protection, differential protection |
| System type | Indoor medium-voltage AC |
| Construction type | Wall-through, fully enclosed |
| Mounting method | Integrated clamped mounting plate |
Model Designation
- L: Current transformer
- F: Wall-through / constructed multi-turn through type
- Z: Epoxy resin casting insulation
- D: Differential protection
- 2: Design sequence code
- 10: Rated voltage class: 10kV
Construction
The LFDZ2-10 features a fully enclosed epoxy resin cast structure, providing high mechanical strength and reliable insulation for indoor use. The primary winding is configured as a multi-turn through-wall type, allowing the primary conductor to pass directly through the mounting plate. The secondary winding and laminated core are completely encapsulated within the cast-resin body, ensuring protection against moisture, dust, and electrical stress. An integrated mounting plate is clamped onto the insulation body and includes pre-drilled holes for secure vertical or horizontal installation, adapting to various switchgear layouts. This construction supports long-term operational stability in medium-voltage indoor distribution environments.
Technical Parameters
Service Conditions
- Installation location: indoor medium-voltage switchgear
- System voltage: 10kV, 11kV and 12kV class systems
- Rated frequency: 50Hz
- Ambient temperature: normally -5°C to +40°C unless otherwise specified
- Installation environment: should be free from severe vibration, corrosive gas, explosive medium, conductive dust, heavy pollution, and abnormal condensation.
- Special environments: For high altitude, coastal, humid, or heavy-pollution environments, the insulation and installation requirements should be confirmed before ordering.
Technical Parameters
The LFDZ2-10 is an indoor wall-through current transformer designed for 10kV, 11kV, and 12kV class systems. It features fully enclosed epoxy resin casting, operates within a standard ambient temperature range of -5°C to +40°C, and complies with IEC standards and GB1208-87. The device supports rated primary currents from 75A to 400A and secondary current of 5A, with multiple accuracy combinations for measurement and protection applications.
| Rated primary current (A) |
Rated secondary burden (Ω) |
1s thermal current Ith (×I1n) |
Dynamic stable current Idyn (×I1n) |
|
|---|---|---|---|---|
| class 0.5 | class D | |||
| 75~200 | 0.8 | 1.2 | 120 | 210 |
| 300~400 | 0.8 | 1.2 | 80 | 160 |
Installation & Wiring
Installation Diagram
The LFDZ2-10 current transformer is designed for wall-through mounting and can be installed vertically or horizontally based on the switchgear layout. It features a mounting plate with four Φ14 holes arranged in a 160mm × 160mm pattern. The wall opening should accommodate a reference window of approximately 95mm, and overall mounting height may vary between 215mm and 275mm depending on orientation and drawing specifications.
Selection & FAQs
Selection Guide
- Select the primary ratio for the feeder operating range. Published options are 75A, 100A, 150A, 200A, 300A and 400A with a fixed 5A secondary; check continuous load, expected growth and instrument range.
- Choose the two-core duty deliberately. Use 0.5/0.5 for two measurement circuits, 0.5/D for measurement plus legacy differential protection, or D/D only where two protection duties are specifically required.
- Reconfirm any D-class protection requirement. D is a legacy designation and should not be assumed equivalent to a modern 5P, 10P, PX or transient class; obtain the excitation, resistance, ratio-error and knee-point data required by the relay study.
- Specify rated output and fault withstand separately. The source page does not provide definitive VA, short-time thermal-current or dynamic-current values, so these must be stated in the technical agreement for the exact ratio and core.
- Approve the installation drawing before panel work. Confirm vertical or horizontal orientation, the four Ø14 holes on a 160 × 160mm pattern, the approximate 95mm opening, overall height, primary interface and terminal direction.
Frequently Asked Questions
Q1: What is the maximum system voltage for this wall-through CT?
It supports 10kV, 11kV, and 12kV class systems. Designed for indoor medium-voltage switchgear at 50Hz. Confirm specific voltage during ordering.
Q2: Are high altitude or coastal installations supported by this CT?
Standard models require environments free from severe vibration and corrosive gases. For high altitude or coastal areas, insulation requirements must be confirmed before ordering.
Q3: What are the thermal and dynamic short-circuit current ratings?
Thermal current (Ith) and dynamic stable current (Idyn) are expressed as multiples of the rated primary current. Exact values depend on the selected 75A to 400A primary rating.
Q4: Which accuracy classes are available for measurement and protection?
The LFDZ2-10 offers class 0.5 for measurement and class D for protection applications. Both operate with a standard 5A secondary current. Contact us for specific burden details.
Q5: Which international standards does this epoxy resin CT comply with?
The transformer complies with IEC standards and the GB1208-87 specification. It features fully enclosed epoxy resin casting for indoor use. Request the compliance certificate for your project.
Q6: How do we order custom primary currents outside the standard range?
Standard rated primary currents range from 75A to 400A. For custom ratios or specific secondary burden requirements, please contact our sales team for factory verification.
Q7: What applications suit this wall-through epoxy resin current transformer?
It is ideal for indoor medium-voltage switchgear up to 12kV. The fully enclosed epoxy casting ensures reliable operation in standard 50Hz systems.