Product Overview
The LFZ2-10 current transformer is an indoor, semi-enclosed, multi-turn-through type epoxy resin cast current transformer for medium-voltage AC systems. It is designed for current measurement, electric energy metering, and relay protection in power systems with rated frequency of 50Hz and rated voltage class of 10kV. For international medium-voltage projects, the product can be positioned for 10kV, 11kV and 12kV class indoor switchgear applications, subject to insulation level, system design and project specification confirmation.
The LFZ2-10 series adopts a multi-turn primary winding structure with epoxy resin cast insulation. The primary winding and secondary winding are wound on the core, and the secondary winding assembly is cast into the resin body for insulation and mechanical protection. The product body includes a mounting plate, rating plate, warning plate, earthing bolt and mounting holes, allowing vertical or horizontal installation in indoor switchgear and cabinet structures.
Product Type
| Item | Specification |
|---|---|
| Product name | Indoor Multi-Turn-Through Epoxy Resin Cast Current Transformer |
| Model series | LFZ2-10 |
| Product structure | Semi-enclosed, multi-turn-through type, epoxy resin casting insulation |
| Voltage class | 10kV, 11kV and 12kV class indoor medium-voltage systems |
| Rated frequency | 50Hz |
| Installation | Indoor switchgear; vertical or horizontal mounting |
| Typical applications | Current measurement, electric energy metering, relay protection, switchgear instrumentation |
Product Display
Applications
- 10kV, 11kV and 12kV class indoor medium-voltage distribution systems
- Medium-voltage switchgear, metering cabinets and feeder panels
- Current measurement and electric energy metering circuits
- Relay protection circuits requiring a reliable secondary current signal
- Indoor wall-through or panel-mounted CT applications
- Industrial substations, distribution rooms and complete electrical equipment
Features
- Multi-turn-through structure: The primary winding uses a constructed multi-turn-through design, suitable for medium-voltage current transformation where a compact indoor CT is required.
- Epoxy resin cast insulation: The secondary winding and core assembly are cast with epoxy resin for insulation stability, mechanical protection and indoor environmental resistance.
- Semi-enclosed construction: The structure provides practical insulation and protection while keeping the product suitable for switchgear mounting and installation access.
- Vertical or horizontal mounting: The mounting plate and installation holes allow flexible installation according to the cabinet layout.
- Clear terminal marking: Primary terminals are marked P1 / P2, and secondary terminals are marked according to the metering or protection winding configuration.
- Metering and protection use: The product is suitable for current measurement, energy metering and relay protection in indoor medium-voltage systems.
Principle
The LFZ2-10 current transformer operates according to electromagnetic induction. The primary current passing through the multi-turn primary winding generates magnetic flux in the core. The secondary winding then outputs a proportional current signal to connected meters, relays or monitoring devices. The epoxy resin insulation separates the primary medium-voltage circuit from the secondary low-voltage measurement circuit.
For metering applications, the selected ratio and accuracy class should match the connected meter burden and required measurement range. For relay protection applications, the protection winding and burden must be coordinated with relay settings and expected fault-current conditions.
Model Designation
The model code can be interpreted as follows:
| Code | Meaning |
|---|---|
| L | Current transformer |
| F | Constructed multi-turn-through type |
| Z | Epoxy resin casting insulation |
| 2 | Design sequence code |
| 10 | Rated voltage class: 10kV class |
Technical Data
| Item | Specification |
|---|---|
| Rated voltage class | 10kV class; applicable to 10kV, 11kV and 12kV class indoor systems by project confirmation |
| Rated frequency | 50Hz |
| Insulation type | Epoxy resin casting insulation |
| Product structure | Semi-enclosed multi-turn-through type |
| Primary terminal marking | P1 / P2 |
| Secondary terminal marking | S1 / S2 for metering winding; protection winding marking according to order configuration |
| Installation method | Vertical or horizontal mounting with mounting plate and fixing holes |
| Service altitude | Not over 1000m under standard service conditions |
| Ambient temperature | -5°C to +40°C |
| Relative humidity | Less than 85% at 20°C reference condition |
| Service environment | No explosive atmosphere, severe vibration, corrosive vapor or insulation-damaging environment |
Terminals
The outlet markings of LFZ2-10 follow standard current transformer polarity conventions. The primary terminals are marked as P1 / P2. For a single metering secondary winding, the secondary terminals are commonly marked as S1 / S2. If the product includes an additional protection secondary winding, the second secondary circuit can be marked separately according to the project requirement.
| Terminal Marking |
Function | Application Note |
|---|---|---|
| P1 / P2 | Primary terminals | When primary current flows from P1 to P2, secondary current flows from S1 to the external circuit. |
| S1 / S2 | Metering secondary winding | Used for current measurement or electric energy metering circuits. |
| Protection secondary | Relay protection winding | Terminal marking depends on the selected protection winding configuration. |
| Earthing bolt | Grounding point | Used for product grounding according to the project wiring and safety requirements. |
Selection Table
The final current ratio, accuracy class, rated output and protection configuration should be selected according to the connected meter, relay, secondary wiring burden and switchgear fault level. Long table headers are wrapped into multiple lines for responsive website display.
| Selection
Item |
Common
Requirement |
Engineering Note |
|---|---|---|
| Rated voltage | 10kV class | For 10kV, 11kV and 12kV class indoor systems, confirm insulation level and applicable standard. |
| Rated frequency | 50Hz | 60Hz applications should be confirmed separately before ordering. |
| Current ratio | Project-specific | Select according to load current, metering range and relay protection setting. |
| Secondary current | 5A or 1A by order | 5A is common for short secondary wiring; 1A may reduce burden for long wiring circuits. |
| Accuracy class | Metering or protection class | Specify each secondary winding separately when both metering and protection are required. |
| Rated burden | Project-specific VA | Total meter, relay and cable burden must not exceed the rated output of each secondary core. |
Note: Final technical parameters shall be confirmed according to the nameplate, approved drawing, technical agreement and factory test report.
Service Conditions
- Installation location: indoor medium-voltage switchgear
- Altitude: not over 1000m under standard service conditions
- Ambient temperature: -5°C to +40°C
- Relative humidity: less than 85% at 20°C reference condition
- The installation environment should be free from explosive atmosphere, severe vibration, corrosive vapor and insulation-damaging conditions.
- For high altitude, high humidity, heavy pollution or special switchgear conditions, technical confirmation is recommended before ordering.
Standards and Compliance
The LFZ2-10 current transformer is designed for indoor medium-voltage current transformer applications. Project requirements may specify IEC or GB current transformer standards according to the final technical agreement. Routine inspection normally includes appearance inspection, ratio test, polarity verification, accuracy test, insulation resistance test and power-frequency withstand test where required.
Installation and Dimensions
The LFZ2-10 current transformer can be installed vertically or horizontally according to the switchgear layout. The product body includes a mounting plate, rating plate, warning plate, earthing bolt and four mounting holes. Before cabinet production, the mounting position, primary conductor path, secondary terminal direction and insulation clearance should be confirmed with the approved outline drawing.
Dimensions
| Item | Dimension / Note |
|---|---|
| Installation direction | Vertical or horizontal installation |
| Mounting structure | Mounting plate with four fixing holes |
| Primary connection | Primary terminals P1 / P2 according to product drawing |
| Secondary connection | Secondary terminal block according to metering/protection configuration |
| Drawing confirmation | Final outline and hole dimensions shall be confirmed before cabinet production |
Safety Notes
- Confirm the model, voltage class, current ratio, secondary current, accuracy class and rated burden before installation.
- Check mounting plate position, conductor clearance, secondary terminal access and earthing arrangement before assembly.
- Install the transformer vertically or horizontally according to the approved switchgear layout.
- Connect primary and secondary terminals according to terminal markings and the project wiring diagram.
- The secondary circuit of a current transformer must not be open-circuited when the primary circuit is energized.
- Before disconnecting meters or relays, short-circuit the CT secondary circuit using an approved shorting block.
- Installation and maintenance shall be performed by qualified medium-voltage electrical personnel.
Ordering Info
Please provide the following information when ordering or requesting a quotation:
- Product model: LFZ2-10
- Rated voltage and system voltage class
- Rated primary current and rated secondary current
- Accuracy class and rated burden for each secondary winding
- Metering or relay protection application requirement
- Installation direction: vertical or horizontal
- Installation drawing, mounting hole requirement and terminal direction
- Service condition if altitude, humidity, pollution level or vibration requirement is special
- Quantity, certificates, test reports, labeling and packaging requirements
Selection Guide
- Confirm voltage class: Select LFZ2-10 for indoor medium-voltage systems around 10kV class, including international 10kV, 11kV and 12kV class applications after insulation confirmation.
- Confirm structure: Use this model when a multi-turn-through epoxy resin cast CT is required for indoor switchgear.
- Select current ratio: Choose the current ratio according to feeder load, metering range and protection setting.
- Specify core function: Define whether the secondary winding is used for measurement, energy metering or relay protection.
- Check burden: The total burden of meters, relays and secondary wiring should not exceed the rated output of the CT.
- Confirm drawing: Check mounting plate, hole positions, conductor path, terminal direction and maintenance access before production.