# Hitachi Energy 315 MVA 765/345 kV OLTC Autotransformer

> High-voltage intertie autotransformer family for 765/345 kV transmission backbones.

> SKU: VF-HE-AUT-315M-765K | Brand: ABB / Hitachi Energy | Category: Power & Energy Equipment / Transformers / High-Voltage & Transmission Power Transformers / Interconnection & Transmission Autotransformers (345-380 kV)

**Voltformer canonical:** https://voltformer.com/product/hitachi-energy-315-mva-765-345-kv-autotransformer - markdown version: https://voltformer.com/product/hitachi-energy-315-mva-765-345-kv-autotransformer.md

## Overview

Hitachi Energy 315 MVA 765/345 kV OLTC Autotransformer is intended for TEİAŞ 380 kV National Grid Backbone Main Interconnection Substation. Configured electrical data: 315 MVA, 765/345 kV primary/secondary voltage, 50 Hz, 3-phase, vector group YNa0d11 and short-circuit impedance 12.5%. Construction: Copper (Cu-Cu); cooling: ONAF; loss class: TEİAŞ 380 kV İletim Standardı. 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:** TEİAŞ 380 kV National Grid Backbone Main Interconnection Substation
- **Target industries:** National Transmission Grids, Mega Power Station Switchyards
- **Brand:** [ABB / Hitachi Energy](https://voltformer.com/brand/abb-hitachi-energy.md) - Global leader in high-voltage power grids and critical industrial infrastructure; Hitachi Energy delivers Resibloc® glass-fibre reinforced dry-type, TrafoStar™ large power transformers and EcoDry seri
- **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. / [Interconnection & Transmission Autotransformers (345-380 kV)](https://voltformer.com/category/power-transmission-transformers/interconnected-grid-autotransformers.md)

## Technical Specifications

| Property | Value |
|---|---|
| Rated power | 315 MVA |
| Primary / secondary voltage | 765 kV / 345 kV (OLTC - project configured) |
| Frequency / phases | 50 Hz / 3-phase - YNa0d11 |
| Short-circuit impedance (Uk) | 12.5% |
| No-load loss P0 | 85.68 kW |
| Load loss Pk | 453.6 kW |
| Calculated efficiency (power factor = 1) | 99.8291% at 100% load; 99.8738% at 50% load |
| Loss class | TEİAŞ 380 kV İletim Standardı |
| Windings | Copper (Cu-Cu) - cooling: ONAF - insulation: Class A |
| Temperature rise | 65 K - sound pressure: 68 dB(A) |
| Mass and dimensions | 185000 kg - 8500×4800×7500 mm |
| Enclosure | IP55 - wheel gauge: 2000 mm |
| LI / AC withstand | 1913 kV peak / 918 kV rms - partial discharge: 5 pC |
| Environment | -25°C / +40°C; altitude ≤ 1000 m |
| Core steel | CRGO Laser-Treated Grain-Oriented Silicon Steel (23ZDMH85 / Baosteel B23R085) |
| Bushings / terminals | Direct Copper Busbar Terminals (Busbar Integrated / IP00-IP31) |

## Standards

- TEİAŞ technical specification
- IEC 60076
- TS EN 60076

## Accessories

**Included:** OLTC, Oil temperature indicator, Online monitoring interface
**Optional:** Tertiary shunt-reactor connection, Online DGA, Bushing monitoring

## Official sources

- https://www.hitachienergy.com/us/en/products-and-solutions/transformers/power-transformers/system-intertie-transformers/autotransformers
- https://www.hitachienergy.com/products-and-solutions/transformers

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

Manufacturer family/application source. Hitachi Energy publishes autotransformers up to 1300 MVA and primary voltages up to 765 kV and higher, generally with OLTC. Exact three-winding and tertiary ratings are project configured. 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 (Project Engineering) - Indicative range: $1,100,000 – $1,350,000 USD
- Delivery time: 2–8 weeks (may vary depending on technical configuration, factory capacity and destination) - Warranty: 48 months
- Compliance candidates: TEİAŞ technical specification, IEC 60076, TS EN 60076. 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-HE-AUT-315M-765K","quantity":1}]}
```

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