LMZC-0.5 φ80, φ100, φ120 Split-Core Current Transformer epoxy cast-resin

Product Overview

The LMZC-0.5 split-core current transformer is an indoor epoxy cast-resin current transformer designed for cable outlet protection in ring network cabinets, medium-voltage switchgear, and indoor cable termination systems. The product is suitable for 6kV to 35kV power systems with rated frequency of 50Hz or 60Hz, and is mainly used to provide secondary current signals for relay protection devices.

Unlike conventional closed-core current transformers, the LMZC-0.5 adopts a split-core opening structure. During installation, the transformer body can be separated into two halves, placed around the existing cable head or cable outlet, then reassembled and tightened with bolts. This structure makes it suitable for installed cable systems, retrofit projects, and ring network cabinet applications where the primary cable cannot be disconnected.

Product Type

Product Display

Main Applications

• Ring network cabinet cable outlet protection
• 6kV to 35kV indoor cable head outgoing line protection
• Medium-voltage switchgear relay protection circuits
• Indoor cable termination and feeder protection systems
• Retrofit installation where the primary cable cannot be disconnected
• Power distribution cabinets and cable branch systems
• Protection signal acquisition for relays and monitoring devices

Key Technical Features

• Designed for cable outlet protection: Suitable for indoor 6kV to 35kV cable head outgoing line applications, especially in ring network cabinets and switchgear.
• Split-core opening structure: The transformer can be separated into two halves and installed around an existing cable without disconnecting the primary circuit.
• Epoxy cast-resin insulation: The cast-resin structure provides mechanical strength, insulation stability, and moisture resistance for indoor service.
• Protection-class output: 10P10 class output is suitable for relay protection applications.
• Multiple aperture sizes: Common inner diameter options include Φ60, Φ80, Φ100 and Φ120, with other sizes available according to project requirements.
• Base-mounted installation: The bottom mounting holes support fixed installation inside cabinets or cable compartments.

Working Principle

The LMZC-0.5 split-core current transformer operates according to electromagnetic induction. The primary cable passes through the transformer window and acts as the primary conductor. When current flows through the cable, the magnetic core induces a proportional secondary current signal in the winding. This signal is supplied to the relay protection device for current detection and protection operation.

Because the transformer is installed around an insulated cable, the primary insulation is mainly provided by the cable itself. The split-core structure must be fully closed and mechanically tightened after installation to ensure stable magnetic coupling and correct secondary output.

Model Designation

The model code can be interpreted as follows:

Technical Data

Rated Primary Current and Output Reference

Note: If project parameters exceed the listed catalogue range, the current ratio, output, and class can be confirmed through technical agreement.

Service Conditions

• Installation location: indoor
• Applicable system: 6kV to 35kV indoor cable outlet system
• Rated frequency: 50Hz / 60Hz
• The installation environment should be free from severe vibration, corrosive gas, conductive dust, explosive medium, and heavy pollution.
• The transformer should be installed around the insulated cable head or outgoing cable according to the cabinet design.
• The split-core contact surface should be clean, aligned, and fully closed before operation.
• For special altitude, humidity, cable diameter, cabinet layout, relay input, or burden requirements, technical confirmation is recommended before ordering.

Standards and Compliance

The LMZC-0.5 split-core current transformer can be supplied according to GB1208-2006, IEC60044-1:2003, and customer-specific project requirements. Final current ratio, rated output, protection class, routine test items, nameplate data, and installation drawing should be confirmed in the technical agreement.

Installation and Dimensions

Model Size and Dimension Reference

Unit: mm. Additional inner diameter options such as Φ60, Φ80, Φ100 and Φ120 can be supplied according to project requirements. Final dimensions, mounting holes, and installation clearance are subject to the approved drawing.

The LMZC-0.5 series adopts a split-core opening structure. During installation, the transformer is separated into two halves, installed around the cable head or cable outlet, then combined into one complete core and tightened with bolts. The bottom of the transformer includes two mounting holes for fixed installation inside the cabinet or cable compartment.

Installation Procedure

1. Check the cable and model: Confirm that the cable outside diameter, cable head size, and cabinet clearance match the selected LMZC model.
2. Open the transformer body: Loosen the locking bolts and separate the transformer into two halves carefully.
3. Place around the cable: Install the two halves around the insulated cable head or cable outlet.
4. Close and align the core: Align the split-core contact surfaces and combine the transformer into a complete core.
5. Tighten the bolts: Fasten the bolts evenly to ensure the core is fully closed and mechanically stable.
6. Fix the base: Use the bottom mounting holes to secure the transformer in the cabinet.
7. Connect secondary wiring: Connect S1 and S2 to the relay protection device according to the wiring diagram.

Connection and Wiring Notes

• Connect the secondary terminals S1 and S2 according to the relay wiring diagram and polarity requirements.
• Check secondary wiring continuity before energizing the primary circuit.
• The secondary circuit of a current transformer must not be open-circuited when the primary circuit is energized.
• Confirm that the connected relay burden does not exceed the rated output of the transformer.
• Keep secondary wiring short and secure where possible to reduce additional burden.
• Secondary grounding and terminal protection should comply with project specifications and local electrical regulations.

Installation and Safety Notes

• Confirm the model, window size, rated primary current, protection class, and rated output before installation.
• Keep the split-core contact surface clean and avoid dust, metal chips, or mechanical damage.
• Do not operate the transformer if the split core is not fully closed or the locking bolts are loose.
• Maintain proper insulation clearance from the cable head, terminals, cabinet frame, and surrounding components.
• Installation, testing, and maintenance should be performed by qualified electrical personnel.

Ordering Information

Please provide the following information when ordering or requesting a quotation:

• Product model: LMZC-0.5, LMZC-80, LMZC-100, or LMZC-120
• Required inner diameter or cable head outside dimension, such as Φ60, Φ80, Φ100, or Φ120
• Rated primary current: 50A, 100A, 150A, 200A, 300A, or 400A
• Accuracy class and rated output requirement
• Rated system voltage and rated frequency
• Ring network cabinet or switchgear model and installation space
• Connected relay model and protection requirement
• Quantity, drawings, certificates, inspection documents, labels, or packaging requirements

Selection Guidelines

1. Confirm cabinet application: Select LMZC-0.5 for ring network cabinet, switchgear, or indoor cable head outlet protection.
2. Confirm cable head size: Choose the window size according to the cable head or outgoing cable outside diameter.
3. Confirm split-core requirement: Use the split-core type when the cable cannot be disconnected or removed during installation.
4. Confirm current rating: Select the rated primary current according to the feeder current and relay protection setting.
5. Check rated burden: The relay input, secondary cable, and terminal block burden should not exceed the rated output.
6. Confirm installation drawing: Verify outline dimensions, mounting holes, terminal position, and cabinet clearance before production or installation.

FAQs