69kV 33kV High Voltage ONAN Oil-Immersed Step-Down Substation Power Transformer
Designed for heavy industrial substations, providing high surge withstand and continuous duty thermal margin under tropical climates.
Explore our custom-engineered transformer lineup manufactured under ISO 9001 quality frameworks, fully compliant with IEC 60076, IEC 61378-1, and TNB Malaysia grid interconnection standards.
Designed for heavy industrial substations, providing high surge withstand and continuous duty thermal margin under tropical climates.
Flame-retardant Class F/H resin insulated dry-type transformer for indoor commercial, data center, and cleanroom industrial facilities.
Epoxy resin cast three-phase isolation unit delivering galvanic isolation, high harmonic dampening, and precise voltage step-down.
Ultra-low no-load loss design engineered with precision step-lap CRGO core laminations for maximum operational efficiency.
Custom engineered for high continuous load factor applications, featuring integrated thermal sensors and PT100 monitoring.
Built to standard IEC 60076-11 specifications, delivering superior dielectric strength and withstand against short-circuit forces.
Electrostatic shielding design protecting sensitive medical diagnostic machinery and precision CNC industrial lines from voltage spikes.
Versatile dry-type isolation system tailored for OEM machinery integration, automated manufacturing cells, and motor drives.
Established in 2004, our specialized transformer manufacturing plant spans over 103,500+ sq. ft. of built-up production space (on 131,500+ sq. ft. total land area). We provide fully integrated, end-to-end OEM engineering for custom rectifier transformers and power distribution equipment exported directly to Malaysia and Southeast Asia.
Unlike standard assembly vendors, every critical component of our transformers — including CRGO core slitting and step-lap lamination, copper and aluminum foil winding, tank fabrication, sandblasting, anti-corrosion spray painting, oil degasification, and final high-voltage routine testing — is executed strictly in-house under a single unified Quality Management System.
Why standard power transformers fail in converter applications and how custom OEM design ensures continuous 24/7 reliability under non-linear loads.
In modern industrial plants across Malaysia — ranging from chemical electrolysis facilities in Bintulu, Sarawak to semiconductor cleanrooms in Kulim, Kedah — the demand for high-current Direct Current (DC) power requires robust rectifier systems. A Rectifier Transformer serves as the physical and electrical bridge between high-voltage AC utility feeds (such as Tenaga Nasional Berhad's 11kV or 33kV networks) and heavy-current semiconductor rectifiers (thyristor or diode bridges).
Unlike standard utility distribution transformers that operate under sinusoidal 50Hz linear loads, a rectifier transformer directly feeds semiconductor switching devices. This non-linear switching injects severe current harmonics ($h = pq \pm 1$, where $p$ is the pulse number and $q$ is an integer) back into the transformer secondary windings. The resulting harmonic spectrum (5th, 7th, 11th, 13th, 23rd, 25th) induces significant secondary phenomena:
Our OEM factory builds custom phase-shifted secondary windings (Extended Delta, Star-Delta combination, or Zig-Zag configurations). By introducing precise physical phase displacements (e.g., $+15^\circ$ and $-15^\circ$ for 24-pulse systems), low-order harmonic currents (5th, 7th, 11th, 13th) cancel out electromagnetic vector-wise within the transformer delta primary winding, preserving grid power quality in compliance with IEEE 519 and Malaysian TNB Electricity Supply Application Handbook guidelines.
Rectifier circuits in metal electroplating, chlor-alkali electrolysis, and arc furnace applications experience frequent external DC busbar short circuits. The mechanical force exerted on transformer coils scales with the square of peak current ($F \propto I_{peak}^2$).
To resist these destructive radial and axial electromagnetic forces, our OEM facility utilizes continuous foil-winding equipment for low-voltage secondary coils, coupled with high-density thermally upgraded pressboard spacers and hydraulically pre-stressed coil clamping rings. This guarantees that the transformer withstands severe through-fault forces without mechanical deformation or turn-to-turn insulation breakdown over decades of continuous operation.
Tailored engineering for specific high-growth industrial sectors operating under tropical environmental conditions across Malaysia.
Heavy DC current supply for chlorine, caustic soda, and chemical electrolysis plants in Bintulu and Kuantan. Custom 12-pulse and 24-pulse oil-immersed ONAN/ONAF units featuring saturated reactors or interphase transformers (IPT) for ultra-smooth DC output voltage control.
Continuous-duty power transformers and electro-processing isolation transformers operating in humid, high-ambient plantation environments. Sealed tank construction with tropicalized C5-M anti-corrosion paint protects against corrosive hydrogen sulfide fumes.
Ultra-clean cast resin dry-type isolation and step-down transformers installed inside Kulim Hi-Tech Park and Bayan Lepas cleanroom facilities. Features low stray magnetic field shielding, electrostatic earth screens, and low sound level execution (<55 dB).
High-reliability dry-type distribution transformers feeding large uninterruptible power supply (UPS) rectifiers and DC power distribution units (PDU). Built with K-factor rating (K-13, K-20) to handle non-linear server switch-mode power supplies without overheating.
Low-voltage, high-current water-cooled or forced-air oil-filled rectifier transformers engineered for continuous electro-galvanizing, zinc plating, and hard anodizing lines in industrial parks throughout Selangor and Ipoh.
Custom OEM multi-winding rectifier transformers supporting polymer electrolyte membrane (PEM) and alkaline water electrolyzers for commercial green hydrogen production projects emerging in East Malaysia's clean energy corridors.
Compare structural options, cooling methods, and rating envelopes across oil-immersed and dry-type OEM transformer lines.
| Specification Parameter | Oil-Immersed Rectifier Transformer | Cast Resin Dry-Type Transformer | High-Voltage Substation Unit |
|---|---|---|---|
| Rating Envelopes | 500 kVA up to 30 MVA | 100 kVA up to 5 MVA | 10 MVA up to 35 MVA |
| Primary Input Voltage | 6.6kV, 11kV, 22kV, 33kV (TNB grid) | 6.6kV, 11kV, 13.2kV, 22kV, 33kV | 33kV, 66kV, 69kV, 132kV |
| Pulse Architecture | 6-Pulse, 12-Pulse, 24-Pulse, 48-Pulse | 6-Pulse, 12-Pulse (K-Factor rated) | Standard Sine Phase / Step-Down |
| Insulation & Fluid | Mineral Oil (IEC 60296) / Synthetic Ester | Class F (155°C) or Class H (180°C) Epoxy | High-Flashpoint Mineral Oil |
| Cooling Method | ONAN, ONAF, OFWF | AN (Air Natural) / AF (Air Forced) | ONAN / ONAF Dual Stage |
| Tropicalization Grade | C5-M Coastal Anti-Corrosion Finish | E2 (Condensation), F1 (Fire Hazard) | IP55 Outdoor Substation Box |
| Harmonic Rating ($K$-Factor) | $K$-13 to $K$-30 continuous harmonic duty | $K$-4, $K$-9, $K$-13, $K$-20 rated | Standard Utility Linear Load |
| Compliance Standards | IEC 61378-1, IEEE C57.18.10, IEC 60076 | IEC 60076-11, BS EN 60076 | IEC 60076, IS 2026, TNB Standards |
Operating high-voltage electrical equipment in Malaysia requires strict adherence to regional grid codes and robust thermal design suited for ambient temperatures reaching 40°C-50°C and 100% relative humidity.
Every custom OEM transformer supplied to Peninsular Malaysia or Sabah/Sarawak (SESB / Sarawak Energy) is engineered to meet local supply voltage tolerances ($\pm 5\%$ steady state, $+10\% / -15\%$ transient) and standard vector groups (e.g., Dyn11, Ynnd11, or phase-shifted combinations).
High ambient heat combined with coastal moisture in areas such as Pasir Gudang, Kemaman, or Bintulu accelerates thermal breakdown and metal oxidation. Our OEM factories implement specialized protection measures:
Complete documentation package including Type Test Reports from accredited independent test labs.
Off-Circuit Tap Changers (OCTC) or On-Load Tap Changers (OLTC) with automatic voltage regulators (AVR).
Vacuum-sealed moisture barrier foil wrap, timber crating, and nitrogen gas pressure filling during sea transit to Port Klang or Pasir Gudang.
Welcoming customer engineers or third-party inspection firms (SGS, Bureau Veritas, TUV) for witness testing in our test bay prior to dispatch.
Direct answers to common questions asked by electrical engineers, EPC contractors, and procurement managers sourcing custom OEM transformers for Malaysia.
We design and manufacture both oil-immersed and cast resin dry-type transformers spanning from 16 kVA up to 35,000 kVA (35 MVA) in primary voltage classes of 6.6 kV, 11 kV, 22 kV, 33 kV, 66 kV, and 69 kV. Custom secondary voltages are engineered precisely to your load specification, whether stepping down to 415V/400V 3-phase, 220V, or specialized low-voltage heavy-current outputs for direct rectifier bridge coupling.
Our OEM engineering team configures multi-pulse phase-shifting vector arrangements (such as 12-pulse star-delta dual secondary windings or 24-pulse systems utilizing multiple phase-shifted transformers). This cancels low-order harmonic currents internally, preventing voltage distortion (THDv) and current distortion (THDi) from violating Tenaga Nasional Berhad (TNB) grid connection requirements or IEEE 519 standard thresholds.
Standard distribution and cast resin dry-type transformers are generally manufactured within 3 to 5 weeks following drawing approval. Custom-designed multi-pulse rectifier transformers, high-capacity power transformers, or units requiring specialized On-Load Tap Changers (OLTC) typically require 6 to 9 weeks. Sea freight transport from our factory to Malaysian ports (Port Klang, Pasir Gudang, or Bintulu Port) takes approximately 12 to 18 days depending on shipping line schedules.
Yes, absolutely. We encourage witness testing for all export orders. Malaysian engineering teams or appointed independent inspectors (such as SGS, TUV, Intertek, or Bureau Veritas) are welcome to inspect materials during production and witness final routine tests in our high-voltage laboratory. Complete certified test dossiers (including guaranteed technical particulars, vector verification, short-circuit withstand calculations, and routine test certificates) are delivered with every transformer.
Foil winding utilizes continuous sheets of electrical-grade copper or aluminum with full-width insulation strips across the coil width. This construction completely eliminates axial mechanical forces during short-circuit faults, drastically reduces eddy current losses caused by high-frequency harmonics, eliminates localized hot-spot temperature rise, and significantly extends transformer insulation life under continuous industrial loading.
We provide a standard 12 to 24-month comprehensive manufacturer warranty on all custom OEM transformers, extendable up to 36 months upon project agreement. After-sales technical support includes remote diagnostic assistance, routine maintenance guidance, supply of spare fittings (such as bushings, Buchholz relays, silica gel breathers, magnetic oil gauges), and on-site commissioning supervision through our regional engineering partners.
Send us your single-line diagram (SLD), voltage ratio specs, load profile, or project tender documents. Our senior transformer application engineers will evaluate your requirements and deliver a technical proposal with guaranteed technical particulars within 24 hours.
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