Photovoltaic/Wind power/Energy storage transformer

New energy substations are power conversion and distribution equipment specially designed for new energy power generation systems. They are mainly used to convert low-voltage alternating current generated by new energy power generation systems into medium-voltage or high-voltage alternating current, and feed electric power into the public grid.They are widely applied in the construction and renovation of 10~110kV small and medium-sized substations and distribution stations, industrial & mining facilities, and mobile operation substations for petroleum, chemical industry, drilling platforms, urban and rural areas.This product features intelligent operation, energy conservation & environmental protection, excellent electrical performance and innovative structural design.

35kV Oil-Immersed Three-Phase Double-Winding Non-Exciting Voltage Regulation New Energy Generation Side for Photovoltaic, Wind Power, Energy Storage Transformers

10kV Oil-Immersed Three-Phase Double-Winding Non-Exciting Voltage Regulation New Energy Generation Side for Photovoltaic, Wind Power, Energy Storage Transformers

FAQs

1. How do transformers handle severe harmonics and distorted waveforms caused by high-frequency inverter outputs in photovoltaic power generation and energy storage systems?

• Answer: Renewable energy inverters and power conversion systems (PCS) generate significant high-order harmonics, causing extra stray losses and localized overheating in transformers. To address this, transformers must incorporate anti-harmonic designs (such as optimized foil winding structures and electromagnetic designs that minimize stray eddy current losses), undergo proper capacity derating during selection, or utilize special transformers complying with specific K-factor standards.

2. How do step-up transformers in photovoltaic and energy storage systems (ESS) adapt to extreme ambient temperatures, wide diurnal temperature swings, and intense outdoor solar radiation?

• Answer: Renewable energy plants are often located in deserts, gobis, or high-altitude regions with extreme temperature fluctuations and intense solar radiation. Transformers must use high-grade insulation systems adaptable to wide temperature ranges (such as Class H insulation), feature advanced UV-resistant anti-corrosion coatings on enclosures and cooling fins, and maintain sufficient thermal margins in design to prevent thermal breakdown under full load and extreme heat.

3. How do dual-secondary or multi-winding transformers safely coordinate with multiple power conversion systems (PCS) in large-scale battery energy storage systems (BESS)?

• Answer: Energy storage plants frequently employ multi-winding transformers (such as dual-secondary transformers) to connect multiple independent or parallel PCS units simultaneously. Transformer designs must possess exceptional short-circuit impedance matching and symmetry to isolate circulating current interference between different converters, withstand strong electrodynamic shock forces during single-side short-circuit faults, and ensure electrical isolation and stability across multiple branches.

4. How do tower-base or nacelle transformers used in wind power generation overcome strict spatial constraints and long-term continuous mechanical vibrations?

• Answer: The interior space of wind turbine generators is extremely limited, and blade rotation generates high-frequency, continuous mechanical vibrations and oscillations. Wind-specific transformers must adopt compact structural designs while applying reinforced seismic resistance and multi-point soft-connection fixation to cores, coils, and internal clamping components to prevent fastener loosening, wire chafing, or internal short circuits under prolonged alternating mechanical stress.

5. What special protections are adopted by step-up transformers in offshore wind farms to combat extreme salt spray, humidity, and marine atmospheric corrosion?

• Answer: The marine environment's salt spray and humidity are highly corrosive. Offshore wind transformers typically utilize hermetically sealed stainless steel (e.g., 316L) enclosures or heavy-duty anti-corrosion coating systems meeting C5-M very high durability classes. Additionally, all electrical terminals, bushing creepage distances, and sealing gaskets undergo special anti-marine-growth, anti-condensation, and anti-salt-penetration designs to ensure maintenance-free or low-maintenance operation over a 25-year design life.

6. How do photovoltaic step-up transformers prevent thermal fatigue and insulation aging when subjected to frequent and drastic load fluctuations caused by day-night cycles and sudden solar irradiance changes (e.g., cloud cover)?

• Answer: PV generation is heavily weather-dependent, causing output power to fluctuate drastically in short periods, which subjects transformer windings to frequent thermal-mechanical cycles and sudden temperature shifts. Premium transformers strictly control hot-spot temperature rises during material selection and thermal design, utilizing high-mechanical-strength conductors and elastic compression structures to resist thermal expansion/contraction stresses and delay fatigue aging of insulation materials.

7. How do transformers in renewable energy plants withstand transient massive short-circuit current surges during grid low-voltage ride-through (LVRT / fault ride-through) events?

• Answer: When a grid fault triggers low-voltage ride-through, transformers must endure short-circuit fault currents several times their rated current within a brief timeframe. This requires transformer cores and windings to possess exceptional electromechanical axial and radial stability, with winding inter-turn insulation and mechanical support structures rigorously verified via short-circuit dynamics simulation to prevent winding deformation or disk displacement.

8. What are the advantages and technical considerations of using eco-friendly natural or synthetic ester oils (such as FR3) in large-scale PV and energy storage pad-mounted transformers?

• Answer: Ester insulating fluids feature high flash points (typically exceeding 300°C), superior fire safety, and complete biodegradability. In ecologically sensitive zones or large BESS applications, ester-filled transformers significantly reduce fire and explosion risks, preventing groundwater contamination even if the tank is breached. Due to their higher viscosity, technical considerations require optimizing cooling channels and efficiency to ensure proper fluid circulation and heat dissipation across high and low temperature ranges.

9. How should the ventilation, cooling, and dust-proof systems of PV and energy storage pad-mounted transformers be designed when operating in dusty, sandy, high-temperature desertified regions?

• Answer: Desert regions face year-round sandstorms and extreme heat. For pad-mounted transformers utilizing forced air cooling or natural ventilation, efficient multi-stage dust-proof louvers, replaceable sand-filters, or totally enclosed external circulation heat exchangers (such as oil-to-air coolers with IP55 protection ratings) must be engineered to prevent fine sand and dust from entering electrical compartments, which causes leakage tracking, short circuits, or clogged cooling pathways.

10. How do transformers handle frequent asymmetric loads and DC bias issues in renewable energy microgrids and off-grid / islanding operation modes?

• Answer: In microgrid or off-grid operation environments, partial non-linear loads or control deviations can easily generate asymmetric three-phase loads and trace DC component injections (DC bias). This causes rapid core half-saturation, surging no-load losses, and abnormal increases in vibration and noise. Transformer designs must appropriately increase magnetic flux density margins, optimize core lamination joints, and enhance DC bias resistance to maintain stable power supply during islanding modes.

Quality Assurance & Core Process：

1. High-Permeability Grain-Oriented Electrical Steel

We utilize Hi-B high-permeability grain-oriented (HPGO) electrical steel—the same grade specified by TBEA and CHINT—as the transformer core material, with standard nominal thicknesses of 0.23 mm and 0.27 mm. Core laminations are manufactured using high-precision cutting equipment to guarantee a burr height of ≤0.02 mm. The assembly incorporates a precision step-lap lamination structure, maintaining optimal clamping pressure without imparting excessive mechanical stress to the electrical steel, combining high-B steel characteristics with an optimized magnetic flux density.

2. High-Conductivity Winding Conductors & Core-Coil Assembly

High-conductivity electrolytic copper or aluminum conductors are selected based on transformer capacity, voltage class, and loss requirements. Incoming materials undergo stringent quality inspections for dimensions, electrical resistance, surface quality, and traceability. During the winding process, conductor tension, winding height, layer insulation, and conductor positioning are precisely controlled to ensure resistance consistency and mechanical stability, thereby minimizing load losses and temperature rise during operation.

During core-coil active part assembly, coil height, axial clamping force, radial support, and spacer block positioning are precisely controlled. Proper mechanical clamping prevents coil displacement during transport, normal operation, and short-circuit conditions. Meanwhile, clamping forces are strictly regulated to avoid excessive stress on conductors and insulation materials. Our mechanical design accounts for both radial and axial electromagnetic forces, safeguarding short-circuit withstand capability and long-term dimensional stability.

3. Advanced Insulation System (Oil-Immersed & Dry-Type)

For oil-immersed transformers, we utilize high-grade insulation materials, including Kraft paper, thermally upgraded paper, pressboard, and transformer-grade laminated board. For dry-type transformers, we employ DMD, NMN, Nomex, fiberglass, and epoxy resin systems. Insulation thickness, overlap width, oil duct dimensions, electrical clearances, and mechanical positioning are strictly regulated. All insulation materials are stored under climate-controlled conditions to minimize moisture absorption and contamination, ensuring stable dielectric strength and long-term insulation reliability.

4. Controlled Vacuum Drying

We apply a controlled drying curve regulated by temperature, vacuum level, and duration parameters, rather than relying on fixed cycle times. The process comprises controlled pre-heating, evacuation, primary drying, and final soak phases, with continuous temperature and vacuum monitoring and logging. End-point determination is based on validated process criteria and moisture limits. This process minimizes residual moisture in cellulose insulation, maximizing dielectric strength, retarding insulation aging, and extending overall service life.

5. Vacuum Epoxy Resin Casting

For cast-resin dry-type transformers, we utilize controlled vacuum casting technology. Resin-to-hardener ratio, material temperature, vacuum level, mixing time, pouring conditions, and curing temperatures are strictly regulated. Vacuum degassing minimizes micro-voids prior to pouring, while controlled curing ensures stable mechanical and thermal properties. Finished coils undergo thorough visual and electrical inspections, including routine partial discharge (PD) testing. This process eliminates internal voids, ensuring reliable insulation performance throughout the transformer's service life.

6. Clean Assembly & Torque Control

Final assembly takes place in a controlled environment to minimize contamination from dust, metallic particles, and foreign objects. Critical components are inspected for cleanliness, dimensional accuracy, and insulation condition. Electrical clearances, lead routing, grounding connections, and mechanical supports are rigorously controlled throughout assembly. Critical bolted joints are tightened to specified torque values using calibrated equipment and fully logged. Prior to sealing the tank or enclosure, a thorough internal inspection ensures no tools, loose parts, or foreign material remain.

7. 100% Factory Routine Testing

Every transformer undergoes 100% routine testing prior to dispatch, complying with applicable IEC standards, approved technical specifications, and customer requirements. Standard test routines include winding DC resistance, voltage ratio, vector group verification, no-load loss and current, load loss and short-circuit impedance, applied voltage withstand, and induced overvoltage withstand tests. Special tests—such as partial discharge (PD), dissipation factor (tan δ), or sweep frequency response analysis (SFRA)—are conducted upon request. Each unit is assigned a unique serial number linked to its material records, manufacturing data, and final test reports, ensuring end-to-end traceability.

Youth Transformer Co.,Ltd.