# Siemens Energy 800 MVA 400/22 kV Generator Step-Up (GSU) Transformer

> Siemens Energy 800 MVA 400 kV generator step-up transformer for high-capacity power plant interconnection to transmission networks.

> SKU: VF-SIE-GSU-800M-400K | Brand: Siemens Energy | Category: Power & Energy Equipment / Transformers / High-Voltage & Transmission Power Transformers / Generator Step-Up Transformers (GSU)

**Voltformer canonical:** https://voltformer.com/product/siemens-energy-800-mva-400-kv-gsu-transformer - markdown version: https://voltformer.com/product/siemens-energy-800-mva-400-kv-gsu-transformer.md

## Overview

Siemens Energy 800 MVA 400/22 kV Generator Step-Up (GSU) Transformer is intended for 500 kV Grid Connection Points for Large Power Plants. Configured electrical data: 800 MVA, 400/22 kV primary/secondary voltage, 50 Hz, 3-phase, vector group YNd11 and short-circuit impedance 16%. Construction: Copper (Cu-Cu); cooling: ODAF; loss class: JEC / IEC SOTA GSU. These values support preliminary engineering selection; verify insulation levels, thermal limits, short-circuit duty, installation conditions and applicable standards against the manufacturer datasheet and the site study.

- **Application:** 500 kV Grid Connection Points for Large Power Plants
- **Target industries:** Nuclear Power Plants, Combined-Cycle Gas Turbine (CCGT) Power Plants, Mega Hydroelectric Power Plants (HPP)
- **Brand:** [Siemens Energy](https://voltformer.com/brand/siemens-energy.md) - The embodiment of German engineering excellence; Siemens Energy sets the industry standard with GEAFOL® cast-resin dry-type transformers, ester-oil network units and transmission-level autotransformer
- **Category:** [Power & Energy Equipment](https://voltformer.com/catalog.md) / **Transformers** / [High-Voltage & Transmission Power Transformers](https://voltformer.com/category/power-transmission-transformers.md): 5 MVA–1000 MVA 110 kV, 154 kV, 380 kV, 500 kV and 1000 kV UHV AC/DC transmission and interconnection power transformers. / [Generator Step-Up Transformers (GSU)](https://voltformer.com/category/power-transmission-transformers/generator-step-up-transformers.md)

## Technical Specifications

| Property | Value |
|---|---|
| Rated power | 800 MVA |
| Primary / secondary voltage | 400 kV / 22 kV (DETC - project configured) |
| Frequency / phases | 50 Hz / 3-phase - YNd11 |
| Short-circuit impedance (Uk) | 16% |
| No-load loss P0 | 176.00 kW |
| Load loss Pk | 1360.0 kW |
| Calculated efficiency (power factor = 1) | 99.8084% at 100% load; 99.8712% at 50% load |
| Loss class | JEC / IEC SOTA GSU |
| Windings | Copper (Cu-Cu) - cooling: ODAF - insulation: Class A (105°C) |
| Temperature rise | 65 K - sound pressure: 70 dB(A) |
| Mass and dimensions | 320000 kg - 11200×6400×8200 mm |
| Enclosure | IP55 outdoor - wheel gauge: 2000 mm |
| LI / AC withstand | 1550 kV peak / 680 kV rms - partial discharge: 30 pC |
| Environment | -25°C / +45°C; altitude ≤ 1000 m |
| Core steel | CRGO Laser-Treated Grain-Oriented Silicon Steel (23ZDMH85 / Baosteel B23R085) |
| Bushings / terminals | 500 kV RIP Kondenser Bushing |

## Standards

- IEC 60076
- IEEE C57
- JEC

## Accessories

**Included:** 400 kV condenser RIP bushings, Continuous online DGA gas monitor, Fiber-optic direct winding temperature sensors
**Optional:** Sensformer® digital telemetry module, Redundant oil-directed cooling pumps, Bushing power-factor monitoring

## Official sources

- https://www.siemens-energy.com/global/en/home/products-services/product-offerings/transformers/power-transformers.html
- https://assets.siemens-energy.com/dam/01d1bc9b-bd06-471b-9f86-b39c00c3f3da/Mobile-substatation-pdf_Original%20file.pdf
- https://www.siemensenergy.com/global/en/home/products-services/product-offerings/transformers.html

- **Source scope:** manufacturer-family
- **Last reviewed:** 2026-09-13

Manufacturer family/application source. Siemens Energy manufactures generator step-up transformers up to 1200 MVA and 765 kV for major thermal, combined-cycle and nuclear power plants. Exact impedance, low-voltage generator busbar interface and transport dimensions require project confirmation. Exact order code, guaranteed losses, dimensions, insulation level, cooling stage, winding material and project options must be confirmed with the OEM before procurement or an SLD study.

## Pricing & Logistics

- Pricing type: RFQ (On Request) - Indicative range: $3,600,000 – $4,200,000 USD
- Delivery time: 2–8 weeks (may vary depending on technical configuration, factory capacity and destination) - Warranty: 60 months
- Compliance candidates: IEC 60076, IEEE C57, JEC. Verify applicability and conformity against the exact offered model and project jurisdiction.

## RFQ

Request a formal factory quotation via Voltformer RFQ:

```json
POST https://voltformer.com/api/v1/rfq
{"companyName":"Example Energy","email":"procurement@example.com","items":[{"skuOrId":"VF-SIE-GSU-800M-400K","quantity":1}]}
```

Full catalog JSON: https://voltformer.com/agent-catalog.json - OpenAPI: https://voltformer.com/openapi.json