# S11 vs S13 vs S20 vs S22 Transformer Loss Comparison

Compare S11, S13, S20 and S22 oil-immersed transformer reference losses at common 10/0.4 kV ratings, preserving the original kW values and 75°C load-loss basis.

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Compare S11, S13, S20 and S22 oil-immersed transformer reference losses at common 10/0.4 kV ratings, preserving the original kW values and 75°C load-loss basis.

## Compare like-for-like reference data

The comparison below uses the common 100, 500, 1,000 and 2,500 kVA capacities from the existing S11/S13/S20 and S22 reference tables. It preserves the original numerical strings, kW units and 75°C load-loss reference. These are selected 10 / 0.4 kV configurations, not a guarantee for every voltage or design.

**Selected common capacities — 10 / 0.4 kV oil-immersed transformers**

| Rated capacity (kVA) | Series | No-load loss (kW) | Load loss (kW) | Load-loss reference (°C) |
| --- | --- | --- | --- | --- |
| 100 | S11 | 0.20 | 1.58/1.50 | 75 |
| 100 | S13 | 0.15 | 1.58/1.50 | 75 |
| 100 | S20 | 0.135 | 1.265/1.20 | 75 |
| 100 | S22 | 0.12 | 1.14/1.08 | 75 |
| 500 | S11 | 0.68 | 5.41/5.15 | 75 |
| 500 | S13 | 0.48 | 5.41/5.15 | 75 |
| 500 | S20 | 0.43 | 4.33/4.12 | 75 |
| 500 | S22 | 0.385 | 3.90/3.71 | 75 |
| 1000 | S11 | 1.15 | 10.3 | 75 |
| 1000 | S13 | 0.83 | 10.3 | 75 |
| 1000 | S20 | 0.745 | 8.24 | 75 |
| 1000 | S22 | 0.665 | 7.415 | 75 |
| 2500 | S11 | 2.29 | 21.2 | 75 |
| 2500 | S13 | 1.60 | 21.2 | 75 |
| 2500 | S20 | 1.44 | 16.96 | 75 |
| 2500 | S22 | 1.28 | 15.27 | 75 |

At capacities up to 500 kVA, paired load-loss values a/b mean Dyn11 first and Yyn0 second. They are two connection-specific values, not a minimum–maximum range.

## Read no-load and load losses separately

No-load loss and rated load loss describe different operating effects. Compare the same capacity, voltage ratio, frequency, connection and reference temperature. A lower value in one row does not replace the complete efficiency, impedance, thermal and installation requirements of the project.

## Relate the comparison to the actual load

Operating-energy comparisons require the energised hours, load profile, applicable loss conditions and energy cost assumptions. Request the required guaranteed losses for the selected design. Do not apply these 10 kV reference losses directly to 11, 13.8, 15, 22 or 33 kV configurations.

Final ratings, configuration, performance and supply scope are defined in the project technical agreement.

[Technical reference tables](https://kestvan.com/technical-data)

[Oil-immersed transformers](https://kestvan.com/products/oil-transformers)

[Prepare a transformer RFQ](https://kestvan.com/distribution-transformer-rfq)

## Technical guides and project preparation

- [Oil-immersed transformers](https://kestvan.com/products/oil-transformers)
- [Technical data](https://kestvan.com/technical-data)
- [Transformer RFQ guide](https://kestvan.com/distribution-transformer-rfq)