# TBEA 31.5 MVA 110/34.5 kV Substation Step-Down Power Transformer (OLTC)

> TBEA 31.5 MVA 110/34.5 kV Substation Step-Down Power Transformer (OLTC) belongs to the Substation Step-Down Power Transformers (110-330 kV) category and is rated at 31.5 MVA with 110/34.5 kV primary/secondary voltage. Application: 110 kV Grid to 34.5 kV Distribution Step-Down Substation. Final ratings must be verified against the manufacturer datasheet.

> SKU: VF-TBEA-PWR-31.5MVA-110 | Brand: TBEA (Tebian Electric Apparatus) | Category: Power & Energy Equipment / Transformers / High-Voltage & Transmission Power Transformers / Substation Step-Down Power Transformers (110-330 kV)

**Voltformer canonical:** https://voltformer.com/product/tbea-31-5-mva-110-34-5-kv-substation-step-down-power-transformer-oltc - markdown version: https://voltformer.com/product/tbea-31-5-mva-110-34-5-kv-substation-step-down-power-transformer-oltc.md

## Overview

TBEA 31.5 MVA 110/34.5 kV Substation Step-Down Power Transformer (OLTC) is intended for 110 kV Grid to 34.5 kV Distribution Step-Down Substation. Configured electrical data: 31.5 MVA, 110/34.5 kV primary/secondary voltage, 50 Hz, 3-phase, vector group YNd11 and short-circuit impedance 10.5%. Construction: Copper (Cu-Cu); cooling: ONAN/ONAF; loss class: Ecodesign Tier 2. 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:** 110 kV Grid to 34.5 kV Distribution Step-Down Substation
- **Target industries:** Regional Grid Substations, Organized Industrial Zones, Large Factory MV Infeeds
- **Brand:** [TBEA (Tebian Electric Apparatus)](https://voltformer.com/brand/tbea-energy.md) - TBEA, one of the world's largest transformer manufacturers, delivers world-leading engineering from 1000 kV UHV AC/DC power transformers to SCB18 cast-resin dry-type, S20/S22 ultra-low-loss hermetic a
- **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. / [Substation Step-Down Power Transformers (110-330 kV)](https://voltformer.com/category/power-transmission-transformers/substation-step-down-power-transformers.md)

## Technical Specifications

| Property | Value |
|---|---|
| Rated power | 31.5 MVA |
| Primary / secondary voltage | 110 kV / 34.5 kV (±8 x 1.25% (OLTC)) |
| Frequency / phases | 50 Hz / 3-phase - YNd11 |
| Short-circuit impedance (Uk) | 10.5% |
| No-load loss P0 | 17.50 kW |
| Load loss Pk | 115.0 kW |
| Calculated efficiency (power factor = 1) | 99.58% at 100% load; 99.71% at 50% load |
| Loss class | Ecodesign Tier 2 |
| Windings | Copper (Cu-Cu) - cooling: ONAN/ONAF - insulation: Class A |
| Temperature rise | 65 K - sound pressure: 65 dB(A) |
| Mass and dimensions | 52000 kg - 5600×3400×4900 mm |
| Enclosure | IP55 - wheel gauge: 1435 mm |
| LI / AC withstand | 550 kV peak / 230 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

- IEC 60076
- TS EN 60076
- KEMA & CESI type-test approved

## Accessories

**Included:** Vacuum OLTC, Buchholz Relay, Temperature Indicators, Pressure Relief Device
**Optional:** Online DGA 8-Gas Analyzer, Fiber Optic Temperature Sensor

## Official sources

- https://en.tbea.com/product_list/48.html

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

Manufacturer portfolio/family source. Confirm the exact order code, guaranteed ratings and project-specific options against the current OEM datasheet before procurement or an SLD study.

## Pricing & Logistics

- Pricing type: RFQ (On Request) - Indicative range: $290,000 – $350,000 USD
- Delivery time: 2–8 weeks (may vary depending on technical configuration, factory capacity and destination) - Warranty: 36 months
- Compliance candidates: IEC 60076, TS EN 60076, KEMA & CESI type-test approved. 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-TBEA-PWR-31.5MVA-110","quantity":1}]}
```

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