EAF Transformer Solution for Kazakhstan’s Steel Industry: Project Practice of HKSSPZ‑12000/10.5 On‑Load Tap‑Changing EAF Transformer

Writer： Hengfeng you electric Time：2026-09-10 views：times

Ⅰ. Project Background of 12 MVA On‑Load Tap‑Changing EAF Transformer in Kazakhstan: Power‑Supply Requirements for Steel‑Making

In high‑energy‑consuming industries such as steel and metallurgy, electric‑arc furnaces represent typical large‑capacity, heavily‑fluctuating industrial loads. EAF operation is characterised by frequent load variations, high power demand and strict voltage‑regulation requirements. Accordingly, EAF power‑supply systems require sufficient capacity, while transformers shall sustain continuous heavy‑duty and moderate‑overload operation and maintain stable supply voltage under diverse production conditions.

The end‑user of this project is a Kazakh enterprise engaged in steel‑equipment manufacturing and trading. In response to practical application requirements, Hengfengyou Electrical supplied five HKSSPZ‑12000/10.5 three‑phase oil‑immersed on‑load tap‑changing EAF transformers. Each unit has a rated capacity of 12 000 kVA, rated high‑side voltage of 10.5 kV and rated low‑side voltage of 328 V, mainly for power conversion and stable power supply of EAF production systems.

Targeting substantial load fluctuation and heat‑dissipation demands during steel‑making, customised design has been implemented for capacity, overload capability, tap‑changing mode and cooling system. The deployment of five large‑capacity EAF transformers delivers scalable, stable and continuous power support for steel‑making processes.

Ⅱ. Selection of 12 MVA EAF Transformer in Kazakhstan: Analysis of On‑Load Tap‑Changing Demands for Steel Industry

Compared with conventional distribution transformers, EAF transformers operate under more complex service conditions. Significant load swings may occur during EAF production. Hence transformers shall satisfy rated‑capacity specifications while maintaining sound thermal stability and operational reliability.

Tailored to Kazakhstan’s steel‑industry application scenarios, the project adopts five 12 000 kVA EAF transformers to form a high‑capacity power‑supply configuration. Major equipment‑selection considerations are listed below:

1. Large capacity and overload capability With 12 000 kVA rated capacity, the units meet power‑supply demands of high‑power EAF systems. Moreover, each transformer possesses 30 % long‑term overload capability, which accommodates periodic heavy‑load conditions in steel‑making and improves adaptability to varying field operating conditions.
2. Voltage‑performance compliance for EAF systems The 10.5 kV / 328 V voltage rating converts medium‑voltage power into low‑voltage power suitable for EAF processes. To secure supply‑voltage stability, each unit is fitted with a 12‑step motor‑driven on‑load tap‑changing system. Voltage adjustment can be performed under energised‑load conditions, eliminating production interruptions caused by off‑circuit tap‑changing.
3. Heat‑dissipation requirements under heavy‑duty operation 12 MVA‑class EAF transformers generate considerable heat at high load. To control temperature rise under continuous‑run and overload conditions, OFWF forced‑oil‑circulation water‑cooling is adopted together with LYSF‑200 water coolers. Enhanced oil circulation and water‑based heat removal optimise thermal management performance.
4. Long‑term service suitability for industrial sites Steel production places high priority on power‑supply continuity. As critical components of EAF power‑supply chains, EAF transformers must sustain stable long‑term operation. Therefore, insulating oil, tap‑changer assemblies, cooling circuits and overall structural design are optimised for non‑stop industrial service.

Ⅲ. Core Solution for Kazakhstan 12 MVA On‑Load Tap‑Changing EAF Transformer

To satisfy customer’s EAF power‑supply requirements, Hengfengyou Electrical specifies HKSSPZ‑12000/10.5 three‑phase oil‑immersed on‑load tap‑changing EAF transformer as core equipment.

Main Technical Parameters

Centred on five 12 MVA large‑capacity EAF transformers, this solution integrates on‑load tap‑changing and OFWF cooling systems to match EAF load profiles. It balances sufficient power‑supply capacity, operational stability, heat‑dissipation performance and voltage‑regulation functions.

Ⅳ. Technical Advantages of 12 MVA On‑Load Tap‑Changing EAF Transformer: Overload, Tap‑Changing and Cooling Systems

1. 12 MVA large‑capacity design for high‑power industrial loads The 12 000 kVA rated capacity delivers ample power‑conversion capacity for high‑power EAF systems. Complemented by 30 % long‑term overload capability, it provides operational margin against peak‑load episodes in steel‑making. This design mitigates thermal stress triggered by temporary load surges and renders the equipment well‑suited for continuous‑process industries such as steel and metallurgy.
2. 12‑step on‑load tap‑changing improves EAF‑side voltage‑regulation performance EAF operational variations impose disturbances on power‑supply networks. Stable and flexible voltage‑regulation constitutes a key technical requirement for EAF transformers. All units adopt 12‑step motor‑driven on‑load tap‑changing fitted with Shanghai Huaming MIII500Y‑72.5/12120 on‑load tap‑changers for step‑wise output‑voltage adjustment according to operating conditions. Unlike off‑circuit tap‑changing which requires shutdowns, on‑load tap‑changing minimises production disruptions and fits industrial processes demanding high‑supply reliability.
3. OFWF forced‑oil‑circulation water‑cooling enhances heat dissipation under heavy load OFWF forced‑oil‑circulation water‑cooling is deployed with dual LYSF‑200 water coolers. Insulating oil serves both insulation and heat‑transfer functions inside transformers. Forced oil circulation accelerates internal heat transfer while water coolers rapidly extract waste heat, boosting heat‑dissipation performance under large‑capacity and heavy‑load conditions. This cooling concept closely matches thermal‑load characteristics of steel‑making EAF‑oriented heavy‑duty applications.
4. Insulating‑oil formulation adapted to industrial operating environments No.25 Karamay insulating oil is selected as insulation and cooling medium. It offers dielectric protection for windings and live components while participating in heat transport. Proper selection of insulating oil paired with optimised cooling systems establishes reliable insulation and heat‑dissipation foundations for long‑term operation of the combined 60 MVA EAF‑transformer fleet.
5. System‑level configuration for continuous‑production scenarios Beyond simple rated‑capacity‑oriented equipment selection, this project realises system‑level optimisation aligned with EAF load behaviour. 12 000 kVA capacity addresses high‑power supply demands; 30 % long‑term overload improves load adaptability; 12‑step on‑load tap‑changing fulfils in‑service voltage‑regulation needs; OFWF water‑cooling resolves heat‑dissipation challenges for large‑size units. Combined technical features constitute a complete EAF‑transformer solution for steel‑making applications.

Ⅴ. Project Implementation in Kazakhstan: Equipment Delivery and Services for Steel Industry

Kazakhstan boasts well‑established steel‑metallurgy industrial chains. Steel‑making, metal processing and related capital‑goods manufacturing generate sustained demand for large‑scale electrical equipment. In such industrial contexts, EAF and other high‑power production assets impose stringent requirements on power‑supply capacity, stability and continuous‑operation capability.

This project serves a local Kazakh steel‑equipment manufacturer and trader. Based on end‑user requirements, Hengfengyou Electrical supplied five HKSSPZ‑12000/10.5 three‑phase oil‑immersed on‑load tap‑changing EAF transformers with customised capacity, tap‑changing and cooling configurations.

Total weight of five units at full‑oil state reaches approximately 189.85 t; each unit measures 4950 × 2700 × 4400 mm. For such large‑industrial‑transformer projects, transportation, on‑site erection, foundation load‑bearing capacity and hoisting conditions shall be comprehensively evaluated during project execution alongside electrical‑parameter specifications.

The warranty period is 12 months counting from equipment commissioning, providing quality assurance for subsequent operation.

For inquiries about EAF transformers, general‑purpose industrial transformers and power‑transmission‑distribution equipment for Kazakhstan and neighbouring markets, Hengfengyou Electrical delivers custom‑engineered solutions tailored to voltage class, capacity, load profile and site conditions. Luna, Regional Manager for Kazakhstan Market, provides project consultation, product selection and commercial coordination. Contact us via hfy@hengfengyou.com.

Ⅵ. Hengfengyou Electrical’s 12 MVA On‑Load Tap‑Changing EAF Transformer and Industrial Power‑Transmission‑Distribution Solutions

Industries including steel, metallurgy and mining feature large load magnitudes, high continuity‑of‑production requirements and complex service conditions. Hence power‑transmission‑distribution equipment selection shall not rely merely on isolated component parameters but shall adopt system‑oriented design matching overall plant‑level power‑consumption profiles.

Hengfengyou Electrical specialises in power‑transmission‑distribution hardware, supplying transformers, switchgears and other power equipment for industrial clients, with customisable configurations for different countries, industries and project‑specific conditions.

As demonstrated by this Kazakhstan steel project, five 12 MVA on‑load tap‑changing EAF transformers are deployed to meet aggregate 60 MVA EAF‑power‑supply needs. Integration of large‑capacity design, long‑term overload capacity, on‑load tap‑changing and OFWF water‑cooling enables robust adaptation to steel‑making operating environments.

Going forward, Hengfengyou Electrical will keep supplying dependable power‑transmission‑distribution equipment for steel, metallurgy, mining, energy‑ and‑infrastructure sectors. Through application‑specific product design and dedicated project services, we help customers build more stable and efficient industrial power‑supply systems.