Hqst Ying Sheng (Huaqiang Sheng) Electronics Read more: talk about the lan transformer surge level standard is how to divide?
lan transformers, critical for power distribution and communication systems, are vulnerable to damaging voltage surges caused by lightning strikes or switching operations. To ensure their resilience, international standards define specific Surge Withstand Capability (SWC) levels, primarily governed by IEEE C62.41 and IEC 61643.
The core concept involves classifying the location within the electrical network, as surge severity varies dramatically:
Category C: The harshest environment. Applies to the service entrance or outdoor lines before the main distribution panel. Surges here are high energy. Standards specify rigorous tests (e.g., IEEE: 10kV/10kA combination wave; IEC: Type 1 SPD tests using 10/350μs current wave).
Category B: Applies to major feeders and branch circuits downstream from the service entrance, within the facility. Surges are significant but less intense than Category C. Test levels are lower (e.g., IEEE: 6kV/3kA; IEC: Type 2 SPD tests using 8/20μs current wave).
Category A: The mildest environment. Applies to outlets and long branch circuits far from the entrance. Surges are typically lower energy. Test levels are the least stringent (e.g., IEEE: 6kV/0.5kA; IEC: Type 3 SPD tests).
Key Standards:
IEEE C62.41.x: Defines recommended surge waveforms and levels (Combination Wave: 1.2/50μs voltage, 8/20μs current) for different location categories (A, B, C) in low-voltage AC power circuits in the US.
IEC 61643-11: Governs Surge Protective Devices (SPDs). Classifies SPDs into Types 1, 2, and 3, which correspond roughly to the protection levels needed for locations analogous to IEEE Categories C, B, and A respectively. Test waveforms (e.g., 10/350μs, 8/20μs) and current levels define each Type.
In essence: Network transformers (and associated protection like SPDs) must be rated or protected according to the surge category (IEEE) or SPD Type (IEC) relevant to their installation point. Category C/Type 1 demands the highest surge withstand capability, while Category A/Type 3 requires less. Compliance ensures equipment can survive expected surge events in its operational environment.
