What transformer is best for solar power plant project?

No single transformer fits all solar photovoltaic(PV)projects universally;customized cast resin dry-type transformers dominate distributed rooftop,commercial rooftop and compact box-type PV substations,while optimized oil-immersed pad-mounted transformers serve large utility-scale ground-mounted solar farms,with low-loss amorphous-core PV-specific designs as the premium option for maximizing long-term power generation revenue.Solar transformers undertake core tasks of stepping up low-voltage alternating current from inverters(690V/400V)to medium voltage 10kV/35kV for grid access,isolating DC bias from inverters and suppressing harmonic pollution unique to fluctuating solar output,making anti-harmonic,overload-resistant and environment-adaptive design the core selection benchmark.

Cast resin dry-type transformers(SCB13/SCB14 high-efficiency series)rank as the top choice for distributed solar,rooftop commercial PV,BESS(battery energy storage)matching and indoor compact PV stations,which accounts for over 82%of newly installed distributed solar transformers globally in recent years.The biggest competitive advantage lies in intrinsic fire safety critical for solar sites:fully epoxy vacuum-cast windings contain no flammable insulating oil,eliminating fire risks from oil leakage,tank rupture or burning liquid spreading when short-circuit faults occur;epoxy resin’s flame retardant property avoids open flame propagation even under winding breakdown,ideal for rooftop installations above shopping malls,factory workshops and residential buildings with dense combustible materials and limited fire rescue access.Structurally sealed solid winding body fully blocks moisture,coastal salt fog and floating construction dust,solving condensation and insulation aging troubles common in semi-outdoor basement PV power rooms;upgraded IP54/IP55 weatherproof enclosure with built-in anti-condensation heater enables reliable outdoor cabinet-type deployment beside string inverters without dedicated fire containment pits required for oil transformers,cutting civil engineering investment noticeably.Equipped with Dyn11 winding connection group,dry-type PV transformers efficiently trap 3rd,5th,7th-order harmonics generated by inverter frequent switching inside delta windings to prevent distorted current feeding into public grid,complying strictly with IEC grid access specifications for renewable power stations.Besides,nearly maintenance-free operation matches solar asset management mode:only annual surface cleaning and temperature inspection are needed without periodic oil sampling,filtration and sealing maintenance work for oil-filled counterparts,greatly reducing annual O&M expense of scattered distributed PV stations across dispersed rooftops.High-efficiency SCB14 grade with ultra-low no-load and load loss further cuts standby power waste during intermittent sunshine,shortening extra equipment cost payback within 3–5 years via annual power saving gains.

For large-scale utility ground-mounted solar farms above 20MW built on open desert,barren land and remote countryside,optimized ONAN/ONAF oil-immersed pad-mounted transformers become the most cost-effective mainstream solution.Superior liquid cooling performance delivers stable heat dissipation under continuous full-load operation of central inverters;larger single-unit capacity(up to dozens of MVA)reduces total transformer quantity and auxiliary cable layout cost compared with split dry-type configuration for same total plant capacity,lowering initial procurement cost by 15%–25%generally.Hermetically sealed corrosion-resistant tank with UV-proof outer coating adapts extreme desert high temperature,sandstorm and seasonal cold ambient;ester-type high-flash insulation oil can replace conventional mineral oil to lower fire hazard for eco-sensitive mountain and wetland solar zones where soil pollution control is strict.However,oil transformers demand dedicated oil containment trench design against possible leakage and quarterly routine oil quality testing,which restricts their application in urban compact rooftop PV projects with narrow installation space.

Premium amorphous-alloy core transformers serve high-profit large PV plants pursuing minimum LCOE(levelized cost of electricity).Their ultra-low core no-load loss slashes idle power waste during intermittent cloudy days with weak irradiation;despite higher upfront purchase price,long-cycle energy saving lifts whole-life power generation income to offset extra investment within 4–6 years,widely specified for national-level large new-energy base projects with strict energy efficiency certification requirements.

In short,project scale,installation environment,fire regulation and long-term economic target jointly finalize the optimal transformer:dry cast resin for distributed/rooftop PV,customized oil-immersed for large open-field solar farms,amorphous-core variant for top-tier high-efficiency PV bases.

APA 7th

Zhang,H.,&Wang,L.(2023).Optimized transformer selection criteria for grid-connected photovoltaic power plants.IEEE Access,11,89214–89223.

MLA 9th

Zhang,Hao,and Lei Wang."Optimized Transformer Selection Criteria for Grid-Connected Photovoltaic Power Plants."IEEE Access,vol.11,2023,pp.89214-89223,

GB/T 7714-2015

ZHANG H,WANG L.Optimized transformer selection criteria for grid-connected photovoltaic power plants[J].IEEE Access,2023,11:89214-89223.