{
  "language": "en",
  "interfaceLanguage": "en",
  "url": "https://voltformer.com/articles/eaf-arc-furnace-and-green-hydrogen-rectifier-transformers",
  "id": "art-17",
  "slug": "eaf-arc-furnace-and-green-hydrogen-rectifier-transformers",
  "title": "Heavy Industry Process Transformers: Electric Arc Furnace (EAF) & Green Hydrogen Rectifiers",
  "summary": "Electrodynamic short-circuit forces from 100 kA arc furnace currents, cyclic thermal stress, OFWF water cooling, and 24-pulse phase-shifting rectifier bridges for electrolysers.",
  "readTime": "9 min read",
  "date": "2026-07-14",
  "author": "Voltformer Heavy-Industry Engineering Group",
  "category": "Special Process Transformers",
  "tags": [
    "EAF",
    "Arc Furnace",
    "Green Hydrogen",
    "Rectifier Transformer",
    "OFWF"
  ],
  "contentMarkdown": "### 1. Extreme Process Duty in Steelmaking & Hydrogen Production\n\nProcess transformers endure severe mechanical and electrical stresses far exceeding standard distribution equipment:\n- **EAF Transformers:** Low secondary voltage ($400 - 1200\\text{ V}$) with massive currents up to **$120\\text{ kA}$**.\n- **Green Hydrogen Electrolysers:** Continuous high-current DC supplies via multi-pulse rectifiers.\n\n### 2. Technical Comparison: EAF vs Hydrogen Electrolyser Transformers\n\n| Parameter | Electric Arc Furnace (EAF) Unit | Green Hydrogen Rectifier Unit (PEM / Alkaline) |\n|---|---|---|\n| **Secondary Current** | **$60\\text{ kA} - 120\\text{ kA}$ AC** | $10\\text{ kA} - 40\\text{ kA}$ DC per bridge |\n| **Short-Circuit Frequency** | **10 to 20 dead short-circuits per heat** | Smooth continuous DC load |\n| **Cooling Method** | Forced Oil-Water Heat Exchangers (**OFWF**) | Forced Oil-Air (**ONAF / OFAF**) |\n| **Pulse Configuration** | Direct furnace electrodes | **24-Pulse ($\\pm 7.5^\\circ$ phase-shifted)** |\n\n### 3. Electrodynamic Short-Circuit Force Formulation\n\nElectrodynamic radial and axial forces on transformer windings scale with current squared ($I^2$):\n\n$$ F_{radial} = \\frac{\\mu_0}{2} \\cdot \\left(\\frac{N \\cdot I_{sc}}{h_w}\\right)^2 \\cdot 2\\pi R_w $$\n\nTo withstand $120\\text{ kA}$ short-circuit forces, EAF coils use hardened copper conductors clamped under $10\\text{ MPa}$ hydraulic pressure.\n\n### 4. 24-Pulse Harmonic Cancellation in Electrolysers\n\nElectrolyser transformers split secondaries into four phase-shifted systems ($+22.5^\\circ, +7.5^\\circ, -7.5^\\circ, -22.5^\\circ$), canceling all harmonic currents up to the 23rd harmonic and achieving **THD-I $< 4.0\\%$**.\n\n*Reference: IEEE Std C57.18.10-2021; IEC 61378-1:2011.*",
  "contentLanguage": "en",
  "sources": []
}