Product Overview

LMZB-24 epoxy resin casting busbar type current transformer, is widely used outdoor for measuring current, electric energy and protective relaying in the electrical system with rated frequency 50Hz or 60Hz and highest voltage for equipment 24kV.  Rated primary current is 400-10000Aand rated secondary current is 5A or 1A.

Key Features

• 24kV-Class Outdoor High-Voltage Adaptation Design:The LMZB1-24 outdoor current transformer features a 24kV rated voltage design with insulation levels reaching 75kV (lightning impulse) / 40kV (power frequency withstand voltage). It strictly complies with GB/T 4703.2 and IEC 60044-2 standards, and is optimized specifically for scenarios such as 20kV and below outdoor substations, ring main units, and cable distribution boxes. Its structural design fully accounts for the long-term operational requirements of high-voltage outdoor environments, effectively resisting voltage fluctuations and insulation aging, reducing the risk of equipment failures caused by insulation breakdown, and ensuring the stable operation of the power system.
•  All-Climate Protection Structure：This product adopts a dual protective barrier composed of silicone rubber composite insulation material and a corrosion-resistant aluminum alloy shell: it has passed 7000 hours of UV aging testing, enabling it to withstand long-term outdoor exposure; it reaches IP68 protection level, allowing continuous operation at 1 meter underwater. Meanwhile, through a specially designed structure, it can resist snowfall of 20mm/h and ice loads of 10mm thickness. Verified by 2000 hours of salt spray testing, it has a creepage distance of 20mm/kV, making it suitable for various harsh outdoor environments such as coastal areas, high-altitude regions, and cold areas, and reducing the impact of climatic factors on equipment performance.
• Dual-Winding High-Precision Measurement System：It integrates a 0.2S-class metering winding and a 5P20-class protection winding. The metering winding maintains a ratio error of ≤±0.2% within the range of 1%~120% rated current, meeting the requirements of high-precision electric energy metering and line loss analysis; the protection winding has a composite error of ≤5% under 20 times the rated current, with a response time of ≤10ms, which can quickly trigger relay protection devices to ensure safe disconnection in case of power grid faults. It is equipped with 2 sets of ratio taps (such as 300/5A, 600/5A), which can be adjusted through an outdoor sealed changeover switch, adapting to different load currents without disassembly, thus improving the flexibility of on-site application.
• Enhanced Safety and Environmental Adaptability：It is built with a pressure balance valve to avoid shell condensation and air pressure deformation caused by temperature differences, and can be optionally equipped with explosion-proof certification (Ex d IIB T4), making it suitable for outdoor areas with flammable and explosive risks. Its anti-electromagnetic interference performance complies with IEC 61000-4-5 standards, and it can resist 60kA lightning strikes (10/350μs waveform). It maintains stable measurement accuracy even in strong electromagnetic environments, providing reliable current monitoring and protection guarantees for 20kV-class outdoor power grids.

Main technical parameter

• Rated voltage: 20 kV or 22kV etc
• Rated secondary current:5Aor1A
• Rated insulation level: 24/50/125 kV
• Standards: IEC60044-1.2003 Part 1: Instrument transformers-Part1: Current transformers or IEC61869-1&2-2012 etc.

Remarks: Upon request we are glad to offer transformers according to other standards or with non-standard technical specs.

Outline