HENGFENGYOU TRANSFORMER|ANSI/IEEE STANDARD TRANSFORMER
HENGFENGYOU TRANSFORMER|ANSI/IEEE STANDARD TRANSFORMER
This customized solution is developed by Hengfengyou Electric for the urban power grid upgrading and renovation project in Iraq, delivering an integrated full-process package of 16 units of SZ-31.5MVA 33kV/11kV on-load tap-changing oil-immersed main transformers.
With years of experience in exporting power transmission and transformation equipment to the Middle East, Hengfengyou Electric’s products strictly comply with IEC 60076, GB 1094 and Iraq’s COSQC power standards. The transformers are tailored to outdoor operating conditions in Iraq, including extreme ambient temperatures up to 55°C, year-round heavy sandstorms, salt fog in southern coastal areas, drastic day-night temperature swings and severe grid voltage fluctuations. Compatible with Iraq’s national 50Hz power grid, they support power transmission at the 33kV level and medium-voltage distribution at the 11kV level, providing stable grid connection and power supply for oil & gas extraction, refining plants, industrial & commercial loads and distributed photovoltaic systems.
All units adopt high-purity electrolytic copper windings and are uniformly equipped with on-load tap changers to accommodate wide-range grid voltage fluctuations. Designed with low no-load loss and low total load loss for energy conservation, they feature a combined ONAN/ONAF dual cooling structure. The transformers are resistant to high temperatures, sand erosion and salt fog corrosion, enabling continuous operation under Iraq’s year-round high temperatures while balancing stable wide-range voltage regulation and long-term low energy consumption.
| Parameter Name | SZ-31.5MVA (33kV/11kV) Model (16 Units) | Remarks |
|---|---|---|
| Equipment Type | Three-phase oil-immersed on-load tap-changing main power transformer | For 33kV/11kV two-stage grid networking in Iraq |
| Rated Capacity | 31500kVA | Main transformer for substations and graded power supply for oilfield plants |
| Rated Frequency | 50Hz | Unified standard frequency of Iraq’s national power grid |
| Rated Line Voltage | HV: 33kV / LV: 11kV | Matches standard voltage levels for power transmission and industrial distribution networks in Iraq |
| Winding Connection Group | Yd11 | Low-voltage delta winding suppresses triple harmonics, suitable for industrial non-linear loads |
| Cooling Mode | ONAN (natural cooling under light load) / ONAF (forced air cooling under high temperature) | Fans automatically activate at 55°C for heat dissipation and shut down under no-load or light load to save energy |
| Maximum Ambient Temperature | 55°C | Adapted to extreme high-temperature working conditions in Basra, southern Iraq |
| Temperature Rise Index | Oil temperature rise: 50K; Winding temperature rise: 55K | Class A insulation allows long-term operation under heavy thermal loads |
| Insulation Class | Class A | High-temperature resistant insulation system for sustained heatwave environments |
| Voltage Regulation Mode | OLTC on-load tap-changer ±8×1.25% | Adapts to extensive voltage fluctuations on Iraq’s power grid |
| Short-Circuit Impedance | 8% | Compliant with relay protection setting standards for Iraq’s power grid |
| No-Load Loss | ＜26kW | Low-loss design cuts power consumption significantly during long-term no-load operation |
| Total Full-Load Loss | ＜168kW | Excellent energy efficiency under full-load conditions, aligning with Iraq’s energy conservation policies |
| Winding Material | High-purity electrolytic copper | Superior electrical conductivity, strong resistance to short-circuit impact and high-temperature aging |
| Operating Environment | Extreme ambient temperature up to 55°C, heavy sandstorms, coastal salt fog, large day-night temperature differences, outdoor substation installation | Specially optimized for dual working conditions: inland desert oilfields and coastal oil & chemical zones in southern Iraq |
| Applicable Standards | IEC 60076, GB 1094, Iraq COSQC access standards | Meets grid access certification requirements of Iraq’s Ministry of Electricity (MoE) |
Tailored for Iraq’s 33kV–11kV two-stage power grid and extreme harsh working conditions of oil & gas industries, the integrated package of 16 SZ-31.5MVA step-up main transformers features six core strengths: bulk integrated delivery, high-temperature and sand-resistant weatherproof design, low no-load & full-load losses, on-load voltage regulation for fluctuating grids, all-copper windings with strong short-circuit resistance and optimized harmonic control for simplified operation & maintenance. It perfectly meets the demands of oil & chemical parks, newly built urban substations and photovoltaic supporting step-up stations across Iraq.
Traditional split procurement of transformers leads to lengthy delivery cycles, incompatible spare parts and inconsistent on-site commissioning standards. Hengfengyou Electric delivers all 16 SZ-31.5MVA units with unified design, manufacturing and logistics integration:
a. The 16 Yd11 connection group main transformers jointly undertake voltage regulation and interconnection tasks for regional 33kV transmission grids and 11kV distribution networks, supplying power to clusters of oilfields and multiple substations in new urban districts;
b. Mass uniform units enable flexible allocation of standby-operating configurations and zoned power supply for multiple sites, supporting load adjustment and matching the expansion of Iraq’s oil & gas bases and nationwide urban power grid reconstruction projects;
c. Unified overall installation dimensions, standardized spare parts and consistent commissioning criteria drastically reduce supporting costs for substation civil engineering, cables and switchgear, lowering clients’ overall investment and long-term spare parts inventory pressure.
The no-load and full-load loss values of the 16 SZ-31.5MVA transformers are strictly controlled below limit thresholds, far exceeding the energy efficiency level of conventional transformers deployed across the Middle East:
a. High-purity electrolytic copper windings paired with ultra-low loss high-permeability silicon steel sheets maintain high energy efficiency under both light no-load and peak full-load operating conditions;
b. Iraq experiences high temperatures all year round with equipment running 24/7. Each transformer saves tens of thousands of kWh of energy loss annually, bringing remarkable overall energy-saving benefits for the 16-unit batch and aligning with Iraq’s energy reduction and new photovoltaic energy development policies;
c. The Class A high-temperature resistant insulation system delivers controllable temperature rise under extreme 55°C ambient conditions, preventing accelerated insulation aging failures caused by high-temperature overload and extending the service life of outdoor equipment.
Aging power infrastructure in Iraq results in wide voltage fluctuation ranges, severe industrial load impacts and volatile photovoltaic power output. All units are equipped with on-load voltage regulation systems to specifically address unstable power supply:
a. Each transformer is factory-fitted with an OLTC on-load tap-changer with ±8×1.25% regulation range, enabling real-time automatic voltage adjustment under load to counteract long-distance line voltage drops on the 33kV transmission side and day-night output fluctuations of distributed photovoltaic systems;
b. Uniform standardized 8% short-circuit impedance fully complies with Iraq MoE power grid design specifications, keeping short-circuit currents under control. Clients are exempt from recalculating protection settings unit by unit, greatly boosting commissioning efficiency for differential, backup and earth fault protection at substations and lowering technical barriers for local Iraqi power technicians;
c. Unified voltage regulation logic across the station ensures synchronous voltage adjustment when multiple transformers operate in parallel, avoiding unbalanced load distribution within the substation.
The equipment structure is comprehensively upgraded to withstand Iraq’s operating environment: extreme 55°C summer temperatures, year-round sandstorms, salt fog in Basra coastal regions and drastic day-night temperature swings:
a. High-pour-point high-temperature specialized insulating oil and high-temperature resistant EPDM sealing components are adopted. Under sustained 55°C heat, oil fluidity and tank sealing performance remain stable without leakage or insulation failure;
b. The outer tank wall features a composite coating system of multi-layer high-temperature resistant epoxy zinc-rich primer plus UV-resistant salt-fog topcoat, resisting sand accumulation, coastal salt fog corrosion and intense high-temperature sunlight exposure, allowing long-term open-air installation in both inland desert oilfields and coastal refining plants;
c. The ONAN/ONAF dual-mode cooling system operates in energy-saving natural cooling mode under light loads in spring and autumn, while forced air cooling activates under 55°C extreme summer heat to stabilize oil temperature year-round and avoid shutdowns caused by heatwave overload.
The low-voltage delta winding effectively offsets triple harmonics, resolving harmonic pollution caused by non-linear loads such as oilfield inverters, large motors and photovoltaic inverters across Iraq’s power grid:
a. Reduces harmonic voltage distortion on the 11kV distribution network, protecting downstream oil & gas extraction equipment, photovoltaic grid-connected devices and industrial & commercial loads in plants;
b. The star-connected high-voltage side enables flexible neutral grounding, matching Iraq’s mainstream 33kV neutral grounding grid architecture for stronger operational stability under grid short-circuit faults and minimal harmonic interference during parallel operation of multiple substations.
Built with high-purity electrolytic copper windings, optimized conductor cross-sections and rigid reinforced winding end supports, all units pass full short-circuit withstand type tests per Iraq COSQC standards:
a. Windings resist deformation and insulation avoids damage during sudden grid short-circuits. The batch of 16 units drastically reduces scattered maintenance and replacement costs for remote unattended oilfield substations;
b. Ultra-low no-load loss eliminates hidden heat risks under long-term light-load high-temperature operation, fitting the unattended operation mode of Iraq’s remote oilfield substations and cutting long-term labor and spare parts investment for maintenance.
Combining Iraq’s 33/11kV power grid parameters, 55°C high-temperature environment, sand & salt fog conditions and COSQC standards, Hengfengyou Electric’s technical team conducts electromagnetic simulation analysis. Key optimizations include widened heat dissipation oil channels, low-loss silicon steel sheets, precisely matched standard 8% impedance and extended insulation creepage distance to suppress partial discharge. 3D structural drawings are specially optimized for iron core vibration reduction, high-temperature composite insulation, double anti-corrosion fuel tanks and a full set of high/low temperature resistant dustproof accessories.
Hengfengyou organizes joint reviews by electromagnetic, process, quality inspection and Middle East project teams to verify grid compatibility, weatherproof structure, ocean transportation dimensions, local certification requirements and batch on-site installation conditions. Mass production only commences after review approval.
Hengfengyou Electric implements full-process quality control for the batch of 16 units under the ISO9001 quality management system:
Full set of factory tests are carried out per IEC, GB, Iraq COSQC and MoE standards, with bilingual Arabic-English test reports issued. All 16 units are tested individually:
Hengfengyou adopts split dust-proof and moisture-proof sealed packaging. Accessories are separately protected in wooden crates, while transformer main bodies are filled with nitrogen for rust and dust prevention, secured on heavy-duty steel supports and wrapped with multi-layer weatherproof tarpaulins. Bilingual documents, certification certificates and spare parts lists are enclosed with each shipment.
The logistics route integrates domestic highway transportation, ocean shipping and local transshipment within Iraq. Customs clearance and overland transportation permits for the 16 large-scale equipment units are processed in advance. Temperature & vibration recorders are installed on every unit throughout transit, with extra anti-dust and anti-salt fog reinforcement for ocean shipping. Units are delivered in batches to oilfield and substation project sites.
Closed-loop quality control covers the entire lifecycle: design, raw material inspection, batch production processes, unit-by-unit factory testing, cross-border batch transportation and on-site installation. Full traceability of quality records is guaranteed, and non-conforming products are prohibited from factory delivery and commissioning.
Hengfengyou provides complete bilingual Arabic-English drawings, test reports, certification documents and high-temperature & sand-proof operation & maintenance manuals upon delivery. Specialized training sessions are offered for Iraqi maintenance personnel covering salt fog inspection, high-temperature heat dissipation management, sand dust protection and OLTC on-load tap-changer maintenance. Standardized unified operation & maintenance procedures are formulated for the 16 identical units to drastically lower technical barriers for clients’ maintenance teams.
This integrated package of 16 SZ-31.5MVA-33/11kV oil-immersed transformers stands as a benchmark bulk export project of Hengfengyou Electric in the Middle East. Optimized for Iraq’s extreme 55°C high temperatures, sand & salt fog environments and volatile two-stage power grid, the solution leverages high-temperature anti-corrosion structures, low-loss all-copper windings, unified on-load voltage regulation systems and integrated bulk design to deliver one-stop solutions for core challenges including power conversion at full-scale substations, stable long-term high-temperature operation, harmonic mitigation and energy conservation.
Hengfengyou Electric maintains in-depth familiarity with Iraq’s COSQC, MoE grid access requirements, IEC and GB standards. Custom full-range oil-immersed transformers for the Middle East market are available to serve nationwide power grid upgrading, oil & gas and photovoltaic construction projects in Iraq. General contractors, project owners and foreign trade partners are welcome to contact us for cooperation inquiries.
Contact Email: sales@hfy-transformer.com
