High Tension Toroidal Current Transformers precision ZCT Zero Sequence Current

The LXK-80/100 Series Zero Sequence Current Transformer (ZSCT) is a high-precision sensing device specifically engineered for ground fault protection in medium-voltage power systems. Designed to work in tandem with small current grounding line selection devices or relay protection units, the LXK series detects residual currents that indicate a phase-to-earth fault.

Featuring a toroidal (ring-type) architecture, these transformers allow all three phase conductors to pass through the center. In a healthy system, the vector sum of the currents is zero. When a leakage or ground fault occurs, the resulting unbalanced magnetic flux induces a secondary current, triggering the protective relay to isolate the fault. With its high sensitivity and excellent linearity, the LXK series is an essential component for the safety of industrial grids and substations.

• High Sensitivity Core Material: Utilizes premium silicon steel or ultra-crystalline cores with high magnetic permeability, ensuring accurate detection of even minute leakage currents (mA level).
• Toroidal "Core Balance" Precision: The balanced winding technique ensures minimal error and prevents nuisance tripping caused by high-frequency noise or external magnetic interference.
• Rugged Epoxy Resin Casting: The entire unit is encapsulated in high-grade flame-retardant epoxy resin. This provides excellent insulation (up to 35kV systems), moisture resistance, and mechanical protection.
• Wide Aperture Options (80mm/100mm): The large center windows (LXK-80 and LXK-100) are designed to accommodate standard high-voltage cables, including those with heavy insulation and shielding.
• Easy Installation: The compact, lightweight design allows for direct mounting around cables in switchgear compartments or cable trenches without requiring primary circuit disconnection.

1. Industrial Power Grids: Ground fault monitoring for large motors, transformers, and distribution lines in factories and mines.
2. MV Switchgear (KYN28/KYN61): Integrated into the cable compartment of metal-clad switchgear for real-time leakage detection.
3. Substation Automation: Providing essential input signals for microprocessor-based protection relays and line-selection devices.
4. Renewable Energy: Monitoring phase balance in solar farm combiners and wind turbine collection systems.

• Zero-Phase Accuracy: Our manufacturing process involves rigorous testing of the magnetic balance to ensure that the transformer does not output a false signal during heavy load startup or three-phase imbalances.
• Anti-Corrosive Terminals: Secondary terminals are made of high-quality brass with protective covers to prevent oxidation in humid electrical rooms or outdoor cabinets.
• Customizable Ratios: We provide factory-direct customization of transformation ratios to match the sensitivity requirements of your specific protective relay brand.
• Long Service Life: The solid-cast construction is designed for 20+ years of maintenance-free operation in indoor or sheltered environments.

Q: How do I choose between the LXK-80 and the LXK-100?

A: The choice depends purely on the outer diameter of your high-voltage cable (including the insulation). The LXK-80 has an 80mm inner diameter, while the LXK-100 provides a 100mm opening for larger or bundled cables.

Q: Can this CT be used for measuring load current?

A: No. Zero sequence CTs are specifically designed to measure the difference (leakage) between phases. For standard load measurement, you should use our LMZ or LZZJ series current transformers.

Q: Does it require a special mounting bracket?

A: The LXK series comes with integrated mounting feet, allowing it to be bolted directly to the bottom plate of a switchgear cabinet or secured around the cable using supportive clamps.

 

  

 

LMZK-10 series cassette current transtormer is suitable for current measurement and microcomputer protection of electrical equipmentin 10KV AC power system. The current transformer has the characteristies of small volume,light weight openable and easy to install . It is widely used in the switch cabinet of compact fully insulated ring main unit. It is easy and fast to install when it is directly stuck on the connected incoming and outgoing cables. It has been widely used in ABB safe ring / plus, uniswitch, Schneider RM6/ SM6, Eaton SVS,Germany GA/ Ge, France FB, South Korea SS and other compact fully insulated ring main unit switch cabinet, as well as in combined substation and cable distribution box.