HENGFENGSHUAI supplies 132kV/33kV and 33kV/11kV on‑load tap‑changing (OLTC) oil‑immersed power transformers as well as complete power distribution system solutions for large‑scale oil‑field and oil‑gas infrastructure projects in Iraq.
Tailored for operating conditions of Iraq oil‑field power grids including severe voltage fluctuation, inrush loads from large‑capacity motors, high desert temperature, coastal salt‑fog corrosion and long‑term continuous operation, HENGFENGSHUAI offers 20MVA‑63MVA high‑voltage main transformers, 10MVA‑31.5MVA secondary‑station transformers, 11kV/0.415kV station service distribution transformers and supporting equipment such as medium‑voltage switchgears.
This complete solution is applicable to central substations, water‑injection pump stations, gas compressor stations and ESP (Electric Submersible Pump) power‑supply systems in oil‑gas blocks including Rumaila, West Qurna, Majnoon and Zubair. Equipment is designed and manufactured in compliance with IEC 60076 and relevant standards, with documentation prepared for Iraq’s COSQC acceptance upon project requirements.
I. Market Demands for Power Systems in Iraq Oil‑Fields
Large‑capacity OLTC Transformer Solution Adapted to 132kV/33kV/11kV Oil‑Field Power Grid of Iraq
Southern Iraq accounts for over 70 % of the country’s crude‑oil output. The Rumaila Oil‑Field alone produces around 1.5 million barrels per day, representing one‑third of Iraq’s total crude‑oil production. Major loads at oil‑field sites consist of large water‑injection pumps, gas compressors and hundreds of ESP well clusters. Most oil districts adopt a hybrid power‑supply mode combining the public utility grid and on‑site self‑owned power plants.
Iraq’s public power‑grid infrastructure is aging. Field measurement data indicates voltage fluctuations of ‑15 % ~ +15 % at oil‑field stations. Startup‑shutdown cycles of large‑capacity motors and voltage drops over long‑distance overhead lines frequently trigger voltage sags and over‑voltage events. The maximum ambient temperature in summer can reach +55 °C. Coastal zones including Basra, Umm Qasr and Al‑Fao suffer severe salt‑fog corrosion, while inland desert areas experience persistent sand‑dust storms. Ordinary off‑circuit tap‑changer transformers show relatively high failure rates under such conditions.
HENGFENGSHUAI delivers a full‑scope OLTC‑based power‑distribution package for oil‑field central stations, covering large‑capacity main transformers of 20MVA‑63MVA, secondary‑station transformers of 10‑31.5MVA and station‑service distribution transformers. It ensures 24‑hour continuous operation of water‑injection pumps, compressors and ESP clusters. The products are widely deployed in new‑build and retrofit projects of central substations, gathering‑transmission stations and integrated water‑injection stations across southern Iraq oil‑fields.
II. Core Challenges Faced by Iraq Oil‑Field Projects
* Severe grid‑voltage fluctuation and heavy inrush loads. Frequent startup‑shutdown of 6‑13 MW large water‑injection pumps and compressors generates massive inrush current, with instantaneous voltage deviation up to ±15 % as recorded on‑site. Off‑circuit tap‑changer transformers cannot perform tap‑switching under load, which may lead to ESP shutdown and motor burnout and consequently production losses.
* Extreme outdoor operating conditions combining desert and coastal environments. Stations are designed for a maximum ambient temperature of +55 °C with frequent sand‑dust storms. Coastal blocks around Basra fall under C5‑M salt‑fog corrosion class. Conventional transformers tend to suffer accelerated insulation ageing, paint‑film peeling and capacity derating under high temperature.
* Special local voltage sequence. Transmission voltage levels adopt 132kV/33kV, secondary‑side distribution runs at 33kV/11kV, and station‑service low‑voltage output is 415 V. This system differs from China’s 110kV/35kV/400 V framework; equipment voltage parameters must match local grid specifications for grid‑connection and commissioning.
* Strict acceptance governed by IEC 60076 and COSQC requirements. Tender projects administered by Basra Oil Company and international oil‑company EPC contractors almost mandate OLTC configuration for oil‑field main transformers. Third‑party type‑test reports and complete documentation are prerequisites for COSQC site acceptance.
* Requirement for long‑cycle continuous reliable operation. Unexpected power outages will force well shutdown and incur substantial financial losses for non‑stop oil‑field production. Transformers must deliver outstanding short‑circuit withstand capability and low failure rate, suited for simplified maintenance regimes in remote desert locations.
III. HENGFENGSHUAI 132‑33‑11 kV OLTC Transformer Solution for Iraq Oil‑Fields
HENGFENGSHUAI provides an integrated turn‑key package including OLTC oil‑immersed main transformers, 132kV/33kV/11kV medium‑voltage switchgears, station‑service distribution transformers and complete protection accessories. Electrical optimizations are implemented for fluctuating‑voltage grids and high‑temperature desert environments to mitigate multi‑device interface‑coordination risks, delivering stable power supply for mega‑scale oil‑field water‑injection pump houses, compressor workshops and ESP well clusters.
System Architecture and Power‑Flow Path
132 kV grid incoming feed → 132/33 kV OLTC main transformer → 33 kV medium‑voltage switchgear → 33/11 kV OLTC secondary transformer → 11 kV busbar supplying water‑injection pumps, compressors and ESP well transformers. Meanwhile, 11/0.415 kV station‑service transformers are deployed to supply power for central‑control rooms and auxiliary site loads.
Core‑equipment Functions
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132/33 kV OLTC Main Transformer: Steps down 132 kV transmission voltage to 33 kV distribution voltage and executes real‑time on‑load voltage regulation to stabilize grid voltage for the whole block.
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33 kV Medium‑voltage Switchgear: Implements circuit breaking/closing for incoming/outgoing feeders, over‑current & short‑circuit protection, metering and measurement & control.
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33/11 kV OLTC Secondary‑station Transformer: Performs secondary voltage reduction down to 11 kV for motor‑grade power supply to water‑injection pumps, compressors and well‑site ESP units.
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11 kV Medium‑voltage Switchgear: Provides protection and control for high‑power motor loads of water‑injection and compression units.
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Station‑service Transformer (11/0.415 kV): Supplies power for central‑control buildings, instrumentation, lighting and on‑site auxiliary facilities.
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Full‑set Protection Accessories: Buchholz relay, pressure‑release device, winding & oil‑surface temperature controllers and OLTC control cabinet.
Solution Capabilities: Real‑time voltage stabilization against inrush loads; compatible with hybrid operation of public grid plus on‑site self‑owned power plants; sustained power supply for ESPs, water‑injection pumps and compressors; voltage‑drop compensation for long‑distance overhead lines; compliance with 7×24‑hour non‑stop oil‑field production.
IV. Recommended Products and Key Specifications
132/33 kV OLTC Oil‑immersed Main Transformer
| Item |
Parameter |
| Rated Capacity |
20MVA, 31.5MVA, 40MVA, 50MVA, 63MVA |
| Rated Transformation Ratio |
132kV / 33kV |
| Tap‑changing Mode |
132±8×1.25 % OLTC on‑load tap‑changing |
| Vector Group |
YNd11 |
| Short‑circuit Impedance |
10.5 % |
| Cooling Mode |
ONAN/ONAF mixed cooling |
| Frequency |
50 Hz (Iraq national standard) |
| Max. Design Ambient Temperature |
+55 °C |
| Anti‑corrosion Class |
C4 for inland desert; C5‑M salt‑fog coating for Basra coastal areas |
| Applicable Standards |
IEC 60076, compliant with Iraq COSQC acceptance requirements |
33/11 kV OLTC Oil‑immersed Secondary‑station Transformer for Oil‑fields
| Item |
Parameter |
| Rated Capacity |
10MVA, 16MVA, 20MVA, 31.5MVA |
| Rated Transformation Ratio |
33kV / 11kV |
| Tap‑changing Mode |
33±4×2.5 % OLTC on‑load tap‑changing |
| Vector Group |
Yd11 |
| Short‑circuit Impedance |
8 % |
| Cooling Mode |
ONAN/ONAF |
| Frequency |
50 Hz |
| Max. Ambient Temperature |
+55 °C |
| Anti‑corrosion Scheme |
C4 / C5‑M, selectable by site location |
11kV / 0.415 kV Station‑service Distribution Transformer
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Transformation Ratio: 11kV / 0.415 kV
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Capacity Range: 250 kVA‑2000 kVA; Vector Group: Dyn11
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ONAN natural cooling, dust‑proof & anti‑corrosion coating; serving central‑control rooms and on‑site auxiliary loads.
Medium‑voltage Switchgears (132kV/33kV/11kV)
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Matched to Iraq oil‑field 132/33/11 kV voltage sequence
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Compliant with IEC‑62271; complete protection functions configured for motor‑generated inrush loads in oil‑field environments.
V. Technical Advantages of HENGFENGSHUAI Transformer Solution for Iraq Oil‑Fields
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Full‑range OLTC configuration for severe voltage‑fluctuation adaptation. Real‑time tap‑regulation under operating load to counteract ±15 % grid‑voltage swings induced by water‑injection‑pump and compressor startup‑shutdown, avoiding production losses from ESP well shutdown. Recognized by Basra Oil Company and international EPC general contractors.
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Specialized design for extreme operating conditions in southern Iraq. Designed for maximum ambient temperature of 55 °C; C4 dust‑sand paint system for inland‑desert sites and C5‑M heavy‑duty salt‑fog coating for coastal oil‑field zones. Fully‑sealed corrugated‑panel/radiator‑equipped transformer tanks resist sand‑wind erosion, slow insulation ageing and extend service lifetime.
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One‑stop complete‑scope delivery. Unified supply of OLTC main transformers, secondary‑station transformers, medium‑voltage switchgears and station‑service transformers with standardized electrical interfaces. It mitigates compatibility risks for EPC contractors and asset‑owners and shortens on‑site erection‑and‑commissioning cycles.
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Strict adherence to IEC 60076 and local acceptance codes. Complete third‑party type‑test reports are available for COSQC documentation filing and site acceptance in Iraq. High‑purity oxygen‑free copper windings deliver robust short‑circuit withstand performance, fitting round‑the‑clock non‑stop oil‑field production.
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Modular and expandable capacity. Single‑unit capacity spans 20‑63 MVA; multiple main transformers can run in parallel to support phased capacity expansion of large‑scale oil‑field central stations, matching the pace of water‑injection‑project expansion and new‑well commissioning.
VI. Application Scenarios
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Central substations of mega‑scale oil‑fields including Rumaila, West Qurna, Majnoon and Zubair
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Power‑supply systems for large water‑injection pump stations (single‑unit pump power rating: 6‑13 MW class)
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Power‑distribution systems for gas compressor stations and crude‑oil export pump stations
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Centralized power‑supply systems for ESP electric‑submersible‑pump well clusters
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33kV/11 kV power‑distribution systems for oil‑gas gathering‑and‑processing plants
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New‑build and upgrade‑revamp projects for power‑supply infrastructure of onshore southern Iraq oil‑fields
VII. Project References
Badra Oil‑Field, Iraq｜31.5MVA 33/11 kV OLTC Transformer Project
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Supplied Equipment: 4 sets of SZ‑31.5MVA 33/11 kV OLTC oil‑immersed transformers plus supporting 33 kV medium‑voltage switchgears
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Project Purpose: Power supply for Badra Oil‑Field secondary substation, serving water‑injection‑pump groups and ESP well clusters and resolving voltage‑drop issues over long‑distance transmission lines.
West Qurna‑1 Oil‑Field Central Station｜2×40MVA 132/33 kV OLTC Main Transformer Project
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Supplied Equipment: 2 sets of SZ‑40MVA 132/33 kV OLTC main transformers together with full‑set protection, measurement and control devices
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Project Purpose: Central power source for West Qurna‑1 block. Operates in joint mode with the public grid and oil‑field self‑owned gas‑fired power plant to stabilize voltage for hundreds of production wells equipped with ESP units and water‑injection sets.
VIII. Frequently Asked Questions (FAQ)
Q1: Why are OLTC on‑load tap‑changers rather than off‑circuit tap‑changers selected for main transformers in southern Iraq oil‑fields?
A: The public utility grid in Iraq oil‑fields is fragile, and inrush loads from water‑injection pumps and compressors are substantial, yielding field‑measured voltage fluctuation up to ±15 %. Off‑circuit tap‑changers require power shutdown for tap‑position adjustment and cannot satisfy real‑time voltage‑stabilization requirements for continuous oil‑field production. Tender documents issued by Basra Oil Company generally mandate OLTC configuration for oil‑field main transformers.
Q2: What are the differences between Iraq oil‑field voltage grades and Chinese domestic specifications?
A: Transmission‑system voltage is 132 kV (replacing China’s 110 kV); medium‑voltage distribution adopts 33 kV/11 kV (replacing China’s 35 kV/10 kV); station‑service low‑voltage is 0.415 kV instead of China’s 0.4 kV. Our transformers are strictly manufactured to local Iraq voltage sequences. Equivalent domestic‑standard markings can also be provided for EPC contractors’ internal reference.
Q3: How to select anti‑corrosion grades for transformers deployed in Iraq oil‑fields?
A: Inland‑desert oil‑fields such as northern Rumaila adopt the C4 dust‑and‑sand‑resistant coating system. Coastal blocks near Umm Qasr and Al‑Fao port must deploy C5‑M heavy‑duty salt‑fog‑resistant coating to withstand marine salt‑fog attack.
Q4: Can this transformer solution adapt to hybrid power‑supply combining public grid and self‑owned on‑site power plants?
A: Yes. The OLTC tap‑regulation range of ±8×1.25 % accommodates complex voltage variations under dual‑source parallel‑operation conditions, supporting parallel‑running scenarios of the utility grid and on‑site gas‑fired self‑owned power stations.
Q5: Does the equipment documentation package satisfy Iraq COSQC acceptance requirements?
A: Yes. Transformers are manufactured per IEC 60076. A complete package including third‑party type‑test reports, factory‑test certificates and full technical documentation supports COSQC review and site acceptance procedures.
If you are an EPC general contractor, oil‑field operator or system integrator for Iraq oil‑gas projects, please provide site environmental parameters, load‑capacity figures and grid‑operating‑condition requirements.
HENGFENGSHUAI Electric ‑ One‑stop professional supplier of transformers for Iraq oil‑field central stations
Email: hfs@hengfengshuai.com
