China Factory 35kV Oil Immersed Power Transformer IEC Standard for Substation Construction

         35kV power transformer is a core middle-high voltage power conversion equipment occupying a vital position in regional power transmission and distribution network system. Serving as the key link between high-voltage transmission grid and low-voltage user distribution network, it steps down 35kV high voltage to 10kV, 6kV or other secondary rated voltages for urban power supply, rural grid reconstruction, industrial park substations, photovoltaic and wind power booster stations, mining projects and chemical enterprise self-owned power stations. Differing from low-voltage distribution transformers, 35kV series equipment bears higher insulation grade and stronger grid fluctuation impact, so overall design focuses on excellent insulation performance, low energy loss, stable voltage regulation and outstanding environmental adaptability, manufactured in strict accordance with global IEC60076, ISO and relevant regional power industry specifications. Jiangsu Tianhua Transformer has decades of R&D and export experience in 35kV transformer products, supplying standard and customized units to global clients across Southeast Asia, Central Asia, Middle East, Africa and South America.

        Our 35kV transformer covers capacity from 500kVA up to 50MVA, with primary rated voltage fixed at 35kV or customized 33kV per local national grid standard; common secondary output voltage includes 10.5kV, 6.6kV and 0.4kV according to downstream distribution requirement. Two tap changer configurations are available: off-circuit tap changer (OCTC) for grids with mild load variation and lower project cost, and on-load tap changer (OLTC) that can adjust voltage under full load without power cut, ideal for new energy power stations with unstable incoming voltage caused by intermittent wind and photovoltaic generation. Two mainstream cooling schemes namely ONAN natural oil natural air cooling and ONAF oil natural forced air cooling are selectable based on installed environment and loading conditions. ONAN suits small-medium capacity units deployed in mild climate zones while ONAF matches large-capacity transformers working in high-temperature tropical areas.

         Global power infrastructure investment keeps rising in recent years, with numerous emerging countries pushing rural electrification, urban grid upgrading and clean energy base construction, creating sustained market demand for high-quality 35kV transformers. Many EPC contractors and local power companies prefer Chinese cost-effective reliable transformers for their grid renovation projects. Tianhua accepts full personalized customization including rated capacity, voltage combination, connection group (YNd11 as default standard), cooling mode and optional intelligent monitoring parts according to clients’ project design drawing and site environment. Every finished transformer undergoes complete routine test, temperature rise test, partial discharge test and lightning impulse withstand test before factory delivery to eliminate potential operational faults