Published 2026-05-09 | Updated 2026-05-09
Short Answer
Choose the oil-immersed transformer voltage class according to the grid voltage and project design, then confirm capacity, loss level, impedance, cooling method, accessories, protection, and required test documents.
Match the Transformer to the Grid Voltage
The first oil-immersed transformer decision is the voltage class required by the local network. A 10kV or 11kV distribution transformer is common in many secondary distribution projects, while 20kV, 35kV, and 110kV classes are selected for different utility, industrial, or substation roles.
Buyers should avoid requesting a price from capacity alone. A 630kVA transformer at one voltage class can require a different design, tank, insulation, protection accessories, and test scope than another 630kVA transformer.
- 10kV or 11kV class: common distribution transformer procurement.
- 20kV and 35kV class: medium-voltage distribution and project-specific networks.
- 110kV class: higher-voltage substation or transmission-related projects.
- Confirm local grid voltage before comparing supplier quotations.
Accessories and Protection Affect the Quote
Oil-immersed transformers can include conservator, radiator, oil level indicator, thermometer, pressure relief device, gas relay, tap changer, terminal box, and other accessories depending on the project.
If the buyer compares offers, each quotation should state the same accessories and test assumptions. A lower quotation may exclude documents, accessories, protection devices, or packing requirements needed for actual delivery.
Documentation for Overseas Projects
International buyers usually need more than a product price. Technical data, outline drawing, nameplate details, test report reference, certificate support, packing list, and shipping dimensions help with approval and logistics.
Jinxing Electric can prepare transformer quotation details around destination country, voltage class, capacity, standard requirement, testing expectation, and project schedule.
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FAQ
1. Can I compare transformer prices by kVA only?
No. Buyers should compare voltage class, loss level, impedance, accessories, test documents, standard, and packing requirement in addition to capacity.
2. What should I send for an oil-immersed transformer quote?
Send voltage ratio, capacity, frequency, phase, connection group, impedance if specified, installation environment, accessories, standard, destination country, and required documents.