Zero sequence current transformer (referred to as "zero sequence CT" or "zero sequence") is used in conjunction with relay protection devices or signal devices when generating zero sequence grounding current in power systems, to activate device components and achieve protection or monitoring.

Hebei Taizhongyan Electrical Equipment Technology Co., Ltd. (referred to as "Hebei Taizhongyan" or "Taizhongyan Electric") has many years of experience in the production of zero sequence current transformers. The TZY-LJK series zero sequence current transformers produced are cable type, with product quality better than the national standard GB1208-2006 "Current Inductors", and have passed the type test of the Electrical Equipment Quality Testing Center of relevant institutions. The products have been widely used in power plants and substations in industries such as Southern Power Grid, State Grid, metallurgy, chemical industry, steel, coal, and building materials.

The TZY-LJK series zero sequence CT produced by "Taizhongyan Electric" adopts high-quality iron core, ABS engineering plastic shell, fully sealed resin casting, good insulation performance, and beautiful appearance; It has the advantages of high sensitivity, good linearity, reliable operation, and easy installation. Its performance is superior to general zero sequence CT, and the product has a wide range of applications, not only suitable for electromagnetic relay protection, but also for electronic and microcomputer protection devices. Users can choose the appropriate zero sequence CT according to the operating mode of the system (effective grounding of neutral point, ineffective grounding of neutral point, grounding through high resistance, grounding through low resistance, grounding through arc suppression coil). There are various aperture specifications (φ 40~φ 360mm and above), angle difference, capacity, transformation ratio, accuracy level, accuracy limit coefficient of high-precision zero sequence CT and high-sensitivity zero sequence CT used in conjunction with small current grounding line selection devices, relays and other products, usually divided into two categories: integral and open type.

Note: 1. The TZY -/LJK series zero sequence CT adopts an iron core and is a commonly used model of zero sequence CT. It is the standard model of zero sequence CT in this manual.

1. Environmental temperature: -20 ℃ to 60 ℃, with a daily average temperature of no more than+40 ℃ (specially customized for use in low or high temperature environments), and a temperature difference between day and night of no more than 80 ℃;

2. Altitude: ≤ 2000m (specially customized high-altitude zero sequence CT for high-altitude use);

3. Atmospheric pressure: 80-110Kpa;

4. Relative humidity of air: ≤ 90% (25 ℃), ≤ 50% (40 ℃);

5. The surrounding medium is free of conductive dust, conductive metals, corrosive gases, mold, etc. that may damage the insulation;

6. The installation site should have wind, rain, sand, and dust prevention facilities.

High‑sensitivity Zero‑sequence Current Transformer Selection Comparison Table (Without J, integral type same as split‑core type)