I. Product Overview

The On‑load Tap‑changing Submerged‑arc Furnace Transformer Is A Special‑purpose Transformer For Smelting Industry. It Is Designed And Manufactured In Accordance With Standards Such As GB1094 And JB/T 8531, Mainly Matched With Submerged‑arc Furnaces (Calcium Carbide Furnace, Ferroalloy Furnace, Silicon Smelting Furnace). The Equipment Can Regulate Secondary Voltage Under Load Without Power‑off, Providing High‑current And Low‑voltage AC Power For Submerged‑arc Furnaces To Meet The Continuous Production Requirements Of Smelting Processes. This Product Is Mainly Of Oil‑immersed Type.

II. Structural Composition

The Complete Unit Consists Of Core Made Of High‑magnetism Cold‑rolled Grain‑oriented Silicon Steel Sheets, Primary Windings, High‑current Secondary Windings, On‑load Tap‑changer, Oil Tank, Cooling System, High‑low Voltage Bushings, High‑current Outlet Device And A Complete Set Of Protection And Monitoring Components. Copper Bar Or Thin Copper Foil Windings Are Adopted On The Secondary Side, And The Outlet Structure Is Specially Reinforced To Adapt To The Working Condition Of Ultra‑large Output Current.

III. Voltage Regulation Features

Equipped With On‑load Tap‑changer, Voltage Regulation Can Be Realized Without Furnace Shutdown During Smelting Production. The Voltage Regulation Range And Tap Steps Can Be Customized According To Smelting Processes. It Can Adapt To Furnace Condition Fluctuations And Material Layer Changes, Flexibly Adjust The Furnace Power And Stabilize Smelting Conditions. It Avoids Production Interruption Caused By Power‑off Operation Required By Off‑circuit Voltage Regulation.

IV. Cooling Modes

Mainstream Cooling Modes Include ONAN (Oil Natural Air Natural), ONAF (Oil Natural Air Forced), OFAF (Oil Forced Air Forced). ONAF Is Commonly Used For Medium‑and‑small Capacities. OFAF (Oil Forced Air Forced) Is Mostly Adopted For Large‑capacity And High‑loss Submerged‑arc Furnace Transformers To Rapidly Dissipate Heat, Strictly Control Temperature Rise And Ensure Long‑term Full‑load Operation.

V. Special Insulation And Anti‑impact Design

Submerged‑arc Furnace Working Conditions Frequently Generate Switching Overvoltage And Short‑circuit Surge Current. The Product Optimizes Internal Electric‑field Distribution, Adopts Vacuum Drying And Vacuum Oil‑filling Processes To Strictly Control Partial Discharge. The Insulation Of Windings And Leads Is Specially Reinforced To Withstand Frequently Fluctuating Loads And Surge Voltages And Reduce The Risk Of Insulation Breakdown.

VI. Optimization Of Short‑circuit Resistance And High‑current Structure

The Secondary Side Operates At Extremely High Working Current. Windings, Leads And Outlet Terminals Are Reinforced And Optimized For Overheat Prevention. The Overall Structure Is Verified By Short‑circuit Mechanical Simulation. The Winding Ends Are Clamped Against Loosening To Resist Frequent Short‑circuit Impacts Caused By Electrode Material Collapse And Improve Equipment Operation Stability.

VII. Loss Control And Noise Reduction Design

The Magnetic Circuit And Winding Structure Are Optimized For Long‑term Full‑load Operation Of Submerged‑arc Furnaces To Reduce No‑load Loss, Load Loss And Additional Harmonic Loss. Vibration‑damping Core, Sound‑insulated Oil Tank And Shock‑absorbing Support Structure Are Adopted To Effectively Reduce Operating Noise And Meet Environmental Control Requirements Of Factory Areas.

VIII. Protection And Intelligent Monitoring Configuration

Standard Equipments Include Gas Relay, Pressure Relief Valve, Oil Level Monitoring, Oil Temperature And Winding Temperature Measuring Devices. Optional Accessories Cover On‑line Monitoring Of Oil Chromatography, Partial Discharge, On‑load Tap‑changer And High‑current Outlet Temperature. It Can Be Connected To Smelting Central Control System To Realize Equipment Condition Monitoring And Early Warning.

IX. Typical Application Scenarios

It Is Widely Used In Submerged‑arc Furnace Production Lines For Calcium Carbide Smelting, Ferroalloy Smelting Including Ferrosilicon, Ferromanganese And Ferrochromium, Industrial Silicon Smelting And Yellow Phosphorus Smelting. As The Core Equipment Of Submerged‑arc Furnace Power Supply System, It Provides Controllable High‑power Heat Source For Arc Smelting And Supports Continuous Production Of Metallurgy And Chemical Industry.