Overview
The LDC-10 / LDC(D)-10 is an indoor wall-through current transformer designed for 10kV, 11kV, and 12kV medium-voltage AC systems. It features a single-turn through-type structure with a porcelain-insulated primary conductor and a cast-resin CT body mounted on the switchgear wall or partition.
This transformer supports measurement, energy metering, relay protection, and differential protection applications. It complies with IEC 61869-1 and IEC 61869-2 standards, with legacy projects referencing IEC 60044-1. The standard secondary current is 5A (1A available by agreement), and it operates at 50Hz or 60Hz per project requirements.
Key Ratings Snapshot
| Parameter | Rating |
|---|---|
| Voltage class | 10kV, 11kV, 12kV |
| Rated insulation level | 12/42/75kV (or 10/42/75kV per project) |
| Primary current | Single-turn through-conductor |
| Secondary current | 5A standard; 1A optional |
| Frequency | 50Hz / 60Hz |
| Application | Measurement, metering, relay protection, differential protection |
| Insulation type | Porcelain (primary), cast-resin (CT body) |
| Standards | IEC 61869-1, IEC 61869-2 |
Model Designation
- L: Current transformer
- D: Single-turn through type / wall-through structure
- C: Porcelain-insulated type
- (D): Differential protection configuration
- 10: Voltage class identification; suitable for 10kV systems and IEC 12kV-class insulation coordination for 10kV, 11kV, and 12kV projects
Construction
The LDC-10 / LDC(D)-10 features a robust indoor construction optimized for wall-through installation in medium-voltage switchgear. The primary conductor is insulated with high-strength porcelain, ensuring reliable performance in 10kV–12kV indoor environments. The current transformer body is fixed directly to the cabinet wall or partition and houses the magnetic core and secondary windings in a cast-resin insulated enclosure. This design provides excellent dielectric strength, mechanical stability, and long-term operational safety under normal and fault conditions.
Technical Parameters
Service Conditions
- Installation location: indoor medium-voltage switchgear or wall-through cabinet structure
- System voltage: 10kV, 11kV, or 12kV class
- Rated frequency: 50Hz / 60Hz according to project requirement
- Rated insulation level: 12/42/75kV reference for IEC-style applications
- Installation form: wall-through / partition-through mounting
- Installation environment: should be free from severe pollution, corrosive gas, explosive medium, heavy conductive dust, and abnormal condensation.
Technical Parameters
The LDC-10 and LDCD-10 are indoor cast-resin wall-through current transformers designed for 10kV–12kV medium-voltage systems. They feature a rated insulation level of 12/42/75kV, comply with IEC 61869-1/-2 standards, and operate at 50Hz or 60Hz. The units support primary currents from 600A to 1500A and secondary outputs suitable for both measurement (class 0.5) and protection applications.
Current transformers are in accordance with the Chinese Standard GB 1208-75.
| Parameter | Value |
|---|---|
| Rated Primary Current (A) | 600, 750, 1000, 1500 |
| Rated Secondary Current (A) | 5 |
| Frequency (Hz) | 50 |
| Rated Output (VA) for Accuracy Class 0.5 | 10 |
| Rated Output (VA) for Accuracy Class B | 15 |
| Insulation Level (kV) | 10/42/75 |
| Rated Short-Time Thermal Current Ith (kA) | 75 I1n |
| Rated Dynamic Current Idyn (kA) | 2.5 Ith |
| 10% Multiple | 15 |
Installation & Wiring
Installation Diagram
The LDC-10 / LDC(D)-10 series is installed through a wall opening in indoor switchgear. The unit is secured via a 314mm × 314mm mounting plate with four φ14 holes. Ensure the primary conductor aligns with the wall-through section and that secondary terminals are accessible for wiring. All dimensions, including wall opening size, mounting hole spacing, and primary conductor length, must be verified against the approved outline drawing before installation.
Selection & FAQs
Selection Guide
- Use LDC-10 / LDCD-10 for the high-current single-turn range. Select 600/5A, 750/5A, 1000/5A or 1500/5A according to continuous bus current, expected growth and the operating range of connected equipment.
- Define whether measurement, protection or differential protection is required. The published references are class 0.5 at 10VA and a protection configuration at 15VA; specify the function and performance of each physical secondary winding.
- Confirm the secondary-current option. A 5A secondary is standard, while 1A is mentioned only by technical agreement. The CT, meters, relays, leads and test block must be engineered as one burden circuit.
- Coordinate the CT with system fault duty. The listed 75 × I₁n short-time thermal current and 2.5 × Ith dynamic current are preliminary references; confirm duration, ratio-specific certification and protection characteristics.
- Approve the complete wall-through interface. Check the porcelain primary section, cast-resin body, 314 × 314mm plate, four Ø14 holes, wall opening, conductor length, clearances, polarity and terminal access before fabrication.
Frequently Asked Questions
Q1: What applications suit this wall-through current transformer?
It is designed for indoor medium-voltage switchgear and partition-through cabinet structures. Rated for 10kV to 12kV systems with 12/42/75kV insulation. Contact us to verify your specific application.
Q2: Which accuracy class is provided for measurement cores?
The standard measurement core offers class 0.5 accuracy for metering applications. Protection cores are also available for relay coordination. Specify your exact ratio and class requirements during inquiry.
Q3: Can this 10kV CT be installed outdoors?
No, it is strictly designed for indoor installation environments. The cast-resin body requires conditions free from severe pollution, corrosive gases, and abnormal condensation. Confirm indoor switchgear compatibility before ordering.
Q4: Are these current transformers compatible with 60Hz power systems?
Yes, they operate at either 50Hz or 60Hz according to project requirements. They comply with IEC 61869-1/-2 and GB 1208-75 standards. Please specify your rated frequency when requesting a quote.
Q5: How are primary current ratings configured for this model?
Standard rated primary currents include 600A, 750A, 1000A, and 1500A with a 5A secondary output. Custom ratios are subject to factory confirmation. Submit your single-line diagram for technical evaluation.
Q6: When are factory tests and certifications performed for this CT?
Specific factory tests and routine inspections are subject to confirmation based on your project requirements. Compliance with IEC 61869 and GB 1208 standards is maintained. Contact our team for detailed testing protocols.
Q7: Why specify the LDC-10 model for indoor switchgear projects?
It provides reliable wall-through current transformation for 10kV to 12kV indoor medium-voltage switchgear. Ensure your inquiry includes system voltage, primary current, and accuracy class. Reach out for official datasheets and pricing.