High-precision Zero-sequence Current Transformer

The SMR-H2L high-precision zero-sequence current transformer maintains excellent accuracy even with low primary-side input current, overcoming the shortcomings of traditional zero-sequence current transformers. It plays a crucial role in the accurate diagnosis and rapid isolation of complex single-phase grounding faults, such as high-resistance grounding, grounding initial phase angle approaching 0°, and low residual current after arc suppression coil compensation. The core of the SMR-H2L high-precision zero-sequence current transformer uses a special material (permalloy or microcrystalline) different from conventional transformer cores. Its characteristic is high permeability in weak magnetic fields, which is the foundation of its high-precision zero-sequence performance. Users can select the appropriate zero-sequence current transformer according to the different operating modes of the system (neutral point grounded or ungrounded, grounded through a large resistor, grounded through a small current bank, or grounded through an arc suppression coil).

The dedicated zero sequence achieves the accuracy requirement of 0.5S (0.2S for metrology grade) within the measurement range of 1% to 120%; and achieves the 5P10 protection accuracy requirement within the range of rated value to 10 times the rated value.

1. High Permeability Toroidal Core and Optimized Magnetic Circuit Design

The product uses advanced soft magnetic materials such as nanocrystalline or ultrafine crystals as the core. These materials have extremely high initial permeability and very low coercivity.

2. Unique Shielding Structure

Built-in multi-layer electromagnetic shielding provides strong anti-interference capabilities and a very clean output signal.

3. Integrated Molding or Fully Sealed Encapsulation Process

The transformer's coil and core are tightly encapsulated together in a robust shell, typically filled with epoxy resin or other high-performance insulating materials. This gives the product excellent mechanical stability; moisture-proof, dust-proof, corrosion-resistant properties, and stable electrical performance.

4. Precision Winding and Symmetrical Structure

The secondary side (output side) coil uses a uniform, symmetrical, and precise winding technique. Symmetrical winding ensures that the transformer's variation error and phase error are very small in different positions and directions; good balance characteristics.

Baoding Simaier Electric Co., Ltd., established on July 1, 2009, is located in the Baoding National High-tech Industrial Development Zone, Hebei Province. The company has a 3,600-square-meter production base, advanced production equipment, a technical team, and an R&D team. We can customize products according to customer needs and strictly implement quality management systems to ensure product quality and production efficiency.