Product Overview
The LZZBJ9-10E economy-type current transformer is an indoor single-phase epoxy cast-resin current transformer for medium-voltage switchgear. It is designed for current measurement, energy metering, feeder monitoring, and relay protection in AC power systems with rated frequency of 50Hz. For international product documentation, this model can be positioned for 11kV and 12kV class indoor switchgear, with final selection confirmed by insulation level, system voltage, and project requirements.
The LZZBJ9-10E is different from larger support-structure CTs such as LZZBJ9-12A1 / A2. It should be written as a more compact and cost-effective economy-type indoor cast-resin CT for standard switchgear panels where the customer needs reliable measurement and protection functions but does not require a larger structural-support transformer body. The product uses epoxy resin casting insulation, top primary terminals, a front secondary terminal box, and a compact base for cabinet installation.
A typical project configuration can be specified as 800A / 0.2S / 15VA with protection-class secondary winding, depending on the final nameplate and relay scheme. The product can also be configured with 5A or 1A secondary output, metering accuracy such as 0.2S, 0.2 or 0.5, and protection classes such as 5P or 10P. This makes it suitable for 11kV / 12kV switchgear feeders, compact metering cabinets, and standard indoor distribution panels.
Product Type
| Item | Specification |
|---|---|
| Product name | Indoor Economy-Type Epoxy Cast-Resin Current Transformer |
| Model | LZZBJ9-10E |
| Structure | Indoor single-phase epoxy cast-resin structure with compact base and secondary terminal box |
| Voltage class | 11kV and 12kV class indoor medium-voltage systems |
| Rated insulation level | 12/42/75kV |
| Rated frequency | 50Hz; 60Hz available by project confirmation |
| Rated secondary current | 5A or 1A |
| Typical rated primary current | 5A to 800A reference range shown in catalogue data |
| Featured configuration | 800A / 0.2S / 15VA with protection-class secondary core by project specification |
| Typical use | Current measurement, energy metering, relay protection, feeder monitoring |
Product Display
The LZZBJ9-10E adopts a compact rectangular cast-resin body with upper primary terminals and a front secondary terminal box. The wiring diagram shows separated measurement and protection secondary circuits, which makes the product suitable for switchgear requiring one metering output and one relay-protection output in a compact installation space.
Applications
- 11kV and 12kV class indoor medium-voltage switchgear
- Compact feeder cabinets, metering panels, incoming panels, and outgoing panels
- Current measurement and electric energy metering circuits
- Relay protection circuits using 5P or 10P protection cores
- Standard indoor distribution systems where a cost-effective cast-resin CT is required
- OEM switchgear projects requiring compact dimensions and simple wiring access
Features
- Economy-type platform: LZZBJ9-10E is suitable for standard switchgear projects where compact structure, practical performance, and controlled cost are important.
- 11kV / 12kV class documentation: The product can be described for international 11kV and 12kV class applications when the 12/42/75kV insulation level is confirmed.
- Epoxy cast-resin insulation: The resin body provides insulation strength, mechanical support, and indoor moisture resistance.
- Measurement and protection outputs: The wiring diagram supports separated metering and protection secondary circuits such as 1S1 / 1S2 and 2S1 / 2S2.
- 800A project option: A typical configuration can be 800A with 0.2S metering accuracy and 15VA burden, combined with a protection-class core.
- Compact secondary terminal box: The front terminal box supports safer wiring, easier inspection, and clearer separation of measurement and protection circuits.
Principle
The LZZBJ9-10E current transformer operates according to electromagnetic induction. The primary current flowing through the primary conductor creates magnetic flux in the internal magnetic core. The secondary windings then output proportional low-current signals, normally 5A or 1A, for meters, energy meters, monitoring devices, and protection relays.
For metering applications, the CT must maintain ratio and phase accuracy within the rated burden. For relay protection, the protection core must provide a dependable signal under fault-current conditions. When the product is specified as 800A / 0.2S / 15VA with a protection-class winding, the metering burden, relay burden, secondary cable length, and system fault level should all be checked before final approval.
Model Designation
| Code | Meaning |
|---|---|
| L | Current transformer |
| Z | Indoor type / cast-resin insulated structure reference |
| ZB | Epoxy cast-resin current transformer series |
| J | Reinforced or structural design reference |
| 9 | Design sequence / product platform |
| 10E | 10kV catalogue series, economy-type version; documented for 11kV / 12kV class projects by insulation confirmation |
Technical Data
| Item | Specification |
|---|---|
| Rated voltage class | 11kV and 12kV class indoor systems; 10kV compatibility by project confirmation |
| Rated insulation level | 12/42/75kV |
| Rated frequency | 50Hz; 60Hz by agreement |
| Rated secondary current | 5A or 1A |
| Rated primary current | 5A–400A, 600A, 800A reference values from catalogue data |
| Accuracy class | 0.2S, 0.2, 0.5, 5P, 10P according to order |
| Rated output | 10VA or 15VA reference values; final burden by ratio and accuracy class |
| Typical featured selection | 800A / 0.2S / 15VA with protection-class secondary winding |
| Short-time thermal current | 60 × I1n, 50 × I1n or catalogue kA value depending on ratio |
| Rated dynamic current | 150 × I1n, 120 × I1n or 100 × I1n depending on ratio |
| Ambient temperature | -5°C to +55°C |
| Applicable standards | IEC 61869-2, GB20840.2-2014; legacy IEC 60044-1 / GB1208 references by project agreement |
Selection Table
The following table is reorganized from the catalogue information for website use. Long table headers and combined accuracy cells are split into multiple lines for better display on responsive product pages.
| Rated
Primary Current (A) |
Accuracy
Class Combination |
Rated
Output (VA) |
Short-Time
Thermal Current |
Rated
Dynamic Current |
|---|---|---|---|---|
| 5–400 | 0.2 / 10P 0.2S / 10P 0.5 / 10P |
0.2S / 0.2 / 0.5: 10VA 5P / 10P: 15VA |
60 × I1n | 150 × I1n |
| 600 | 50 × I1n | 120 × I1n | ||
| 800 | 50 × I1n | 100 × I1n |
Note: The table is for preliminary selection. Final ratio, accuracy class, rated burden, short-time thermal current, dynamic current, terminal marking, insulation level, and routine test requirements shall be confirmed according to nameplate, approved drawing, and factory test report.
800A Configuration
| Configuration
Item |
Recommended
Specification |
Engineering Note |
|---|---|---|
| Current ratio | 800A / 5A or 800A / 1A | Choose 5A for conventional systems or 1A for lower burden and longer secondary wiring. |
| Metering accuracy | 0.2S | Suitable for higher-accuracy metering where the meter and burden are properly matched. |
| Rated burden | 15VA project configuration | Confirm total burden of meter, relay, wiring, and terminal connections. |
| Protection class | 5P or 10P by relay requirement | Protection core should be coordinated with relay setting and expected fault current. |
| Voltage class | 11kV / 12kV class | Confirm 12/42/75kV insulation level and project standard. |
Dimensions
| Item | Catalogue Reference | Engineering Note |
|---|---|---|
| Overall length | Approx. 272mm reference | Compact economy-type body for indoor switchgear installation. |
| Overall height | Approx. 190mm reference | Check cabinet vertical clearance before assembly. |
| Base width | Approx. 150mm reference | Confirm mounting base and bottom fixing holes by approved drawing. |
| Terminal box | Front secondary terminal box | Used for separated metering and protection secondary wiring. |
| Primary terminals | Top P1 / P2 terminal arrangement | Confirm busbar or cable lug connection and phase clearance. |
Terminals
The wiring diagram shows a primary winding marked P1 / P2 and two secondary circuits. The first secondary circuit is typically used for metering, and the second secondary circuit is typically used for protection. Terminal marking must always follow the approved wiring diagram and nameplate.
| Terminal | Function | Application Note |
|---|---|---|
| P1 / P2 | Primary terminals | Used for primary current direction and polarity reference. |
| 1S1 / 1S2 | Metering secondary winding | Used for energy meter, measuring meter, or monitoring device connection. |
| 2S1 / 2S2 | Protection secondary winding | Used for relay protection circuit where protection class is specified. |
| Grounding point | Protective grounding | Secondary circuit grounding shall follow project electrical safety practice. |
Service Conditions
- Installation location: indoor medium-voltage switchgear
- Rated voltage: 11kV and 12kV class systems by project confirmation
- Rated frequency: 50Hz; 60Hz by agreement
- Ambient temperature: -5°C to +55°C
- Indoor environment should be free from conductive dust, corrosive gas, explosive medium, heavy pollution and abnormal condensation.
- For high humidity, coastal, high altitude, heavy pollution or special cabinet layouts, insulation distance and creepage coordination should be confirmed before ordering.
Standards and Compliance
For new international projects, the LZZBJ9-10E current transformer should be specified according to IEC 61869-2 current transformer requirements and GB20840.2-2014 where GB documentation is required. Older references such as IEC 60044-1 and GB1208 may be listed only as legacy catalogue references when required by customer documents. Routine tests may include ratio test, polarity check, accuracy verification, insulation test, power-frequency withstand test, and other tests according to the final technical agreement.
Installation and Dimensions
The LZZBJ9-10E is intended for compact indoor switchgear installation. Before cabinet production, the top primary terminal spacing, bottom mounting holes, front terminal-box direction, secondary wiring path, phase-to-ground clearance, and maintenance access should be confirmed with the approved drawing. Because this is an economy-type model, mechanical fit and terminal accessibility should be checked carefully to avoid conflicts with busbar arrangement or low-voltage wiring ducts.
Safety Notes
- Confirm voltage class, insulation level, current ratio, secondary current, accuracy class, rated burden, and protection class before production.
- Check primary terminal spacing, busbar clearance, mounting holes, secondary terminal access, and grounding position before switchgear assembly.
- Connect primary and secondary terminals according to polarity marks and approved wiring diagram.
- The CT secondary circuit must not be open-circuited while primary current is flowing.
- Before disconnecting meters or relays, short-circuit the secondary circuit with an approved shorting device.
- One point of the secondary circuit should be grounded according to project electrical safety practice.
- Installation and commissioning shall be performed by qualified medium-voltage electrical personnel.
Ordering Info
- Product model: LZZBJ9-10E
- Voltage class: 11kV or 12kV class
- Rated primary current and rated secondary current: 5A or 1A
- Featured option if required: 800A / 0.2S / 15VA with protection class
- Metering and protection accuracy class combination
- Rated output / burden for each secondary winding
- Protection class requirement: 5P, 10P or project-specific requirement
- Rated short-time thermal current and dynamic current
- Mounting drawing, terminal direction, wiring diagram and switchgear layout
- IEC standard requirement, routine test report, certificate, label language and packaging requirement
Selection Guide
- Confirm voltage class: Use 11kV and 12kV class wording for international projects, then verify 12/42/75kV insulation level.
- Confirm economy-type suitability: Select LZZBJ9-10E when the project needs compact, cost-effective indoor CT installation rather than a large support-structure CT.
- Select current ratio: Use catalogue ratios such as 5A–400A, 600A or 800A according to feeder load and protection setting.
- Specify metering core: Use 0.2S for higher-accuracy metering, or 0.2 / 0.5 for standard measurement circuits.
- Specify protection core: Use 5P or 10P according to relay requirements and fault-current coordination.
- Verify burden: Confirm that meter burden, relay burden and secondary cable resistance do not exceed rated output, especially for 15VA project configurations.
- Approve drawings: Confirm dimensions, mounting holes, top terminal spacing and secondary terminal-box layout before production.