LZZBJ9 Current Transformer

1. Product Overview

LZZBJ9 series current transformer is a core high voltage primary component widely applied in 10kV & 35kV medium voltage power distribution systems. It adopts fully epoxy resin cast insulation structure, featuring high mechanical strength, excellent insulation performance, moisture-proof, dust-proof and arc-resistant advantages.

This CT is specially designed to convert high primary large current into standard low secondary current signal, supporting electric energy metering, circuit protection and real-time current monitoring. It is perfectly matched with withdrawable switchgear, ring main unit, transformer cabinet and metering panel for global industrial, commercial and new energy power projects.

2. Key Advantages

1. Integrated epoxy casting structure, compact size, stable insulation performance, long service life.
2. Multiple accuracy classes available for metering & dual-purpose protection.
3. Optional 5A / 1A secondary output, compatible with all international standard meters and relays.
4. Built-in shielding layer to optimize internal electric field distribution, reduce partial discharge.
5. Simple fixed mounting structure, easy installation inside medium voltage cubicles.
6. Support 50Hz / 60Hz dual frequency, meet power grid standards of various overseas regions.
7. Complete specifications of current ratios, customizable according to project design demands.

3. Technical Specifications

4. Internal Structure Composition

1. Primary conductive bushing: Connect high voltage main bus, transmit primary load current.
2. Epoxy resin insulation body: Isolate high voltage part from secondary circuit, resist external impact.
3. Silicon steel iron core: Generate alternating magnetic field for electromagnetic induction conversion.
4. Secondary winding: Induce proportional standard secondary small current.
5. Internal shielding layer: Improve electric field uniformity, lower partial discharge value.
6. Mounting base: Fix the whole CT on cabinet mounting plate.
7. Secondary terminal block: External wiring port for energy meters, protection relays and monitoring devices.

5. Working Principle

The product operates on the electromagnetic induction law. When high current passes through the primary conductor of the current transformer, alternating magnetic flux is generated inside the iron core. The magnetic flux cuts the secondary winding and induces proportional secondary current.

The secondary output current is standardized as 5A or 1A, which can be transmitted to metering instruments, protection components and monitoring equipment. It realizes two core values: electrical isolation between high voltage primary system and low voltage secondary equipment, and conversion of large current into measurable signal for measurement & protection.

6. Application Scope

• Medium voltage withdrawable switchgear
• Ring main unit (RMU)
• Transformer inlet & outlet cabinet
• High voltage metering cabinet
• Busbar protection cabinet
• Industrial factory power distribution station
• Commercial complex power supply system
• Photovoltaic & energy storage medium voltage station
• Municipal power grid engineering projects

7. Installation Instructions

1. Check product appearance before installation to confirm no crack, scratch or damage on epoxy shell. Verify model, current ratio, accuracy class and rated voltage conform to project drawing requirements.
2. Reserve enough installation space inside the cabinet, keep distance between CT and live components to avoid insulation interference.
3. Wear soft protective tools during busbar assembly; do not apply strong extrusion or impact force on CT body.
4. Connect secondary wires to terminal block tightly, mark each wire number clearly as per wiring diagram.
5. The metal mounting base of CT must be connected to cabinet PE ground wire reliably.
6. Complete insulation resistance test, polarity test and transformation ratio test before system power transmission.

8. Critical Safety Precautions

1. All installation, maintenance and testing work must be operated by certified professional electrical technicians.
2. Never open or disconnect the secondary circuit while primary side is energized. Open-circuit secondary will generate dangerous high voltage, causing equipment damage and personal injury.
3. Cut off all upstream power supply, complete power cut-off, test and ground operation before overhauling CT.
4. Do not place conductive metal objects near secondary terminals during operation.
5. Stop running immediately if abnormal noise, odor or surface discharge appears, cut off power and carry out full inspection.
6. Keep product nameplate and factory wiring diagram properly for later maintenance reference.

9. Order Information

Please provide below technical requirements when placing orders:

1. Complete model: LZZBJ9
2. Rated voltage (10kV or 35kV)
3. Primary / secondary current ratio
4. Required accuracy class (metering or protection type)
5. Secondary output current (5A / 1A)
6. Installation space limit (if customized size needed)
7. Order quantity
8. Target market applicable standard (IEC standard by default)

10. Packing & Export Note

Each LZZBJ9 current transformer is packed with independent foam shockproof package, then loaded into export carton. All cartons are reinforced with binding tape to prevent collision damage during sea & land transportation. Outer package can attach neutral English label without brand logo, matching overseas customs clearance and warehouse storage demands.