Overview
The LDZB(J)7-10L / TPOL-10 Type is an indoor wall-through epoxy cast-resin current transformer rated for 11kV and 12kV class medium-voltage systems. It features a solid epoxy resin insulation body, designed for reliable performance in switchgear, busbar compartments, and distribution panels with rated frequencies of 50Hz or 60Hz.
This transformer supports standard secondary outputs of 5A or 1A and offers accuracy classes such as 0.2S, 0.5, and 10P for metering and protection applications. It is suitable for current measurement, energy metering, relay protection, and control circuits in IEC-compliant installations, particularly in retrofit projects requiring TPOL-10 equivalent functionality.
Key Ratings Snapshot
| Parameter | Rating |
|---|---|
| Voltage class | 11kV / 12kV |
| Insulation level | 12/42/75kV |
| Rated frequency | 50Hz or 60Hz |
| Primary current | 20A – 2000A |
| Secondary current | 5A, 1A (2A on request) |
| Accuracy classes | 0.2S, 0.5, 10P |
| Core types | Measurement, metering, protection, dual-protection |
| Installation type | Indoor wall-through |
| Insulation material | Epoxy cast-resin |
| Application standard | IEC 61869-2 |
Model Designation
- L: Long-body variant for special cabinet depth or busbar layout
- LDZB(J)7-10: Indoor epoxy cast-resin wall-through current transformer series
- TPOL-10 Type: Russian-style pass-through current transformer equivalent application reference
- 10: Catalogue voltage-class reference; documented internationally as 11kV / 12kV class by insulation confirmation
- 5A / 1A: Rated secondary current options
- 0.2S / 0.5 / 10P: Typical metering and protection accuracy class options
Construction
The LDZB(J)7-10(L) / TPOL-10 Type current transformer features a robust epoxy cast-resin body that provides high dielectric strength, mechanical durability, and resistance to environmental factors. The wall-through design includes a mounting flange for secure installation through switchgear partitions or busbar compartments. Primary conductors pass directly through the central aperture, while secondary windings are terminated at a terminal block embedded in the resin housing. This construction ensures electrical isolation between the medium-voltage primary circuit and low-voltage secondary circuits, supporting safe and accurate operation in demanding indoor medium-voltage environments.
Technical Parameters
Service Conditions
- Installation location: indoor switchgear, distribution devices and busbar compartments
- Rated voltage: 11kV and 12kV class systems by project confirmation
- Rated frequency: 50Hz or 60Hz
- Installation position: any position, subject to mechanical support and drawing approval
- Ambient environment: non-explosive and free from conductive dust, corrosive gas and insulation-damaging vapors
- Special conditions: for cold-climate, high-humidity, coastal, high-altitude or special seismic projects, service conditions should be confirmed before ordering
Technical Parameters
The LDZB(J)7-10L / TPOL-10 is a cast-resin wall-through current transformer designed for indoor medium-voltage applications. It supports 11kV and 12kV class systems with a standard insulation level of 12/42/75kV, operates at 50Hz or 60Hz, and accommodates primary currents from 20A to 2000A. Compliance with IEC 61869-2 and other international standards ensures reliability across diverse project requirements.
LDZB(J)7-10
| Rated Primary Current (A) |
One-Second Thermal Current Ith/1s (kA Virtual Value) |
Dynamic Current Idyn (kA Peak) |
Accuracy Classes Combination |
Rated Secondary Output (VA) | ||
|---|---|---|---|---|---|---|
| 1S/2S | 0.2 | 0.5 | 10P | |||
| 400 | 36 | 80 | 0.2/10P10 0.5/10P10 |
10 | 10 | 15 |
| 600(630) | 56 | 100 | ||||
| 750(800) | 63 | 110 | ||||
| 1000 | 80 | 120 | ||||
| 1200(1250) | 100 | 130 | ||||
| 1500(1600) | 100 | 130 | ||||
LDZB(J)7-10-L
| Rated Primary Current (A) |
One-Second Thermal Current Ith/1s (kA Virtual Value) |
Dynamic Current Idyn (kA Peak) |
Accuracy Classes Combination |
Rated Secondary Output (VA) | ||
|---|---|---|---|---|---|---|
| 1S/2S | 0.2 | 0.5 | 10P | |||
| 400 | 36 | 80 | 0.2/10P15 0.5/10P15 10P10/10P15 0.2/10P10/10P10 0.5/10P10/10P10 |
20 | 20 | 20 |
| 600(630) | 56 | 100 | 30 | 30 | ||
| 750(800) | 63 | 110 | 40 | 40 | ||
| 1000 | 80 | 120 | 30 | |||
| 1200(1250) | 100 | 130 | ||||
| 1500(1600) | 100 | 130 | ||||
Installation & Wiring
Outline Dimensions
The outline dimensions define the wall opening size, flange mounting details, primary terminal positions, busbar hole locations, secondary terminal orientation, and required maintenance clearance. These dimensions must be verified against the approved outline drawing before cabinet fabrication to ensure compatibility with switchgear layout and busbar alignment.
Selection & FAQs
Selection Guide
- Measure the existing wall opening, flange holes, partition thickness and cabinet depth before choosing standard or long-body L type.
- Select a 20A–2000A ratio from load, metering and fault studies, with special attention to thermal/dynamic duty above 800A.
- Choose 1A, 5A or special 2A secondary and specify one, two or three independent 0.2S/0.5/5P/10P cores.
- Calculate each burden and confirm the exact 10VA–40VA output, FS/ALF and secondary lead arrangement.
- Verify TPOL-10 retrofit dimensions, pass-through or threaded primary interface, P1/P2 direction, 12/42/75kV clearances and grounding.
Frequently Asked Questions
Q1: Can this wall-through current transformer be used on 11kV systems?
Yes, it supports 11kV and 12kV class systems. The standard insulation level is 12/42/75kV for indoor medium-voltage applications. Please confirm your specific system voltage during ordering.
Q2: What are the environmental requirements for installing this cast-resin CT?
It requires indoor installation free from conductive dust, corrosive gases, and explosive environments. The unit can be mounted in any position subject to mechanical support. Contact us for high-humidity or coastal project specifications.
Q3: How is the short-circuit withstand capacity specified for this model?
Short-circuit capacity is defined by the one-second thermal current and dynamic peak current parameters. These values scale with the rated primary current from 20A to 2000A. Refer to the technical datasheet for exact kA ratings.
Q4: Which accuracy class combinations are available for protection and measurement?
Multiple accuracy class combinations are available to suit both metering and protection requirements. The exact secondary winding configurations depend on your rated primary current selection. Please provide your single-line diagram for factory verification.
Q5: Are these current transformers customizable for high-altitude projects?
Standard units are designed for normal indoor conditions. For high-altitude, cold-climate, or high-humidity environments, special design considerations apply. Please contact our engineering team to confirm service conditions before placing your order.
Q6: When are special service conditions required before ordering?
Special conditions apply for cold-climate, high-humidity, coastal, high-altitude, or special seismic projects. Standard units suit normal indoor environments without conductive dust or corrosive gases. Confirm your specific site conditions with our team.
Q7: Why choose the TPOL-10 for indoor switchgear applications?
It provides medium-voltage current measurement with a standard 12/42/75kV insulation level. The cast-resin design ensures consistent performance in distribution devices and busbar compartments. Request the IEC 61869-2 compliance certificate for your project.