35 kV Oil-Immersed Power Transformer (S11 Series)

35 kV oil-immersed power transformers in the published S11 schedule cover three-phase ratings from 50 kVA to 40,000 kVA. The tables below separate the 50–630 kVA configurations from the 800–40,000 kVA configurations. They show reference voltage combinations, vector groups, no-load and load losses, no-load current and short-circuit impedance. Use the exact project model and approved manufacturer drawing to confirm the final values before procurement.

How to Read the 35 kV Transformer Tables

The smaller 50–630 kVA group lists a 35 kV high-voltage winding with a ±5% tap range, a 0.4 kV low-voltage winding and a Yyn0 vector group. The larger models list different secondary voltage options and Yd11; some models also list a 38.5 kV high-voltage option. These are distinct configurations, not interchangeable settings on one unit. Confirm voltage, frequency, tap arrangement and vector group against the approved single-line diagram.

The first table expresses loss figures in watts (W). The second table expresses its loss figures in kilowatts (kW): for example, 1.23 and 9.9 for the 800 kVA model. The former page labeled both tables in W, which made the larger-model values misleading. The numerical values below are preserved from the published schedule; request the signed technical data sheet for contractual or efficiency calculations.

What to Confirm Before Ordering

Decision	Project information to provide	What the final data sheet should confirm
Electrical duty	Rated capacity, maximum demand, primary and secondary voltage, phase, frequency	Selected model, winding ratings and tap range
Network connection	Single-line diagram, neutral and earthing arrangement, upstream protection	Vector group, terminal arrangement and impedance
Losses and performance	Required efficiency evaluation and operating load profile	Guaranteed no-load and load loss units, reference temperature and test method
Site conditions	Indoor or outdoor location, ambient temperature, altitude and available space	Cooling method, enclosure or tank arrangement, dimensions and mass
Acceptance	Applicable standards, required tests, certificates and delivery documents	Approved drawings, routine test report and final nameplate

For replacement work, include photographs of the existing transformer nameplate, the oil containment and foundation area, bushing positions and cable or busbar connections. These details can determine whether a nominally similar kVA model actually fits. For new substations, confirm the transformer interface with the high-voltage switchgear and low-voltage distribution equipment before approving layout drawings.

Read our transformer sizes guide for capacity ranges and the transformer sizing guide for load calculations. Send the project data through the contact page to request a matching technical schedule.

Download a Project RFQ Worksheet

For a structured inquiry, download the 35 kV oil-immersed transformer project specification and RFQ worksheet (PDF). It separates buyer requirements from supplier confirmations and is not a certified, model-specific datasheet.

50–630 kVA Reference Parameters

800–40,000 kVA Reference Parameters

All listed values are reference data for model selection. Final dimensions, weights and electrical values must follow the approved project drawings and manufacturer data sheet.