ETS Group
    BESS Transformers — view 1 of 3
    Battery Storage
    300MVA
    Max Capacity
    132kV
    Voltage Class
    99.4%
    Efficiency
    30yr
    Design Life
    Battery Storage · Bidirectional · Cyclic

    BESS Transformers

    Purpose-built for battery energy storage systems — bidirectional power flow, cyclic overload capability, and harmonic tolerance for grid-scale BESS applications.

    ENATS 35-1
    EU EcoDesign Tier 2
    IEC 60076
    IEEE C57
    IEEE C57.159
    ISO 9001
    ISO 14001
    Capacity Range
    1 MVA – 300 MVA
    Voltage Class
    Up to 132 kV
    Cooling
    ONAN / KNAN / ONAF / KNAF
    Standards
    IEC 60076 / IEEE C57
    Power Flow
    Bidirectional
    Insulation
    Mineral Oil / FR3 / Midel
    Installation Support available on request
    Support from an ETS engineer during installation and commissioning, available on request.
    Type Tested
    Warranty
    Global

    Engineering Features

    Bidirectional Power Flow

    Designed for charge/discharge cycling with optimised winding configuration for reverse power flow.

    Technical Data

    ParameterRange / Value
    Rated Power1 – 300 MVA
    Primary Voltage11 – 132 kV
    Secondary Voltage400 V – 36 kV
    Frequency50 / 60 Hz
    Power FlowBidirectional
    Cycle Rating5,000+ cycles/year
    K-FactorK13 – K20
    Ambient Temp-20°C to +55°C
    Insulation FluidMineral / FR3 / Midel
    Design Life30+ years

    Standard range parameters — custom specifications available on request.

    Related glossary terms

    electricalK-FactorRating that indicates a transformer's ability to handle harmonic-rich loads from VFDs, UPS systems, LED drivers, and other non-linear loads.electricalInrush CurrentThe transient surge of magnetizing current that flows when a transformer is first energized. Can reach 8–12 times the rated full-load current.electricalVoltage RegulationThe percentage change in secondary voltage from no-load to full-load, expressed as a percentage of the rated secondary voltage.electricalFerroresonanceA nonlinear resonance phenomenon involving the interaction between a transformer's magnetizing inductance and system capacitance, causing dangerous overvoltages.standardsIEEE C57North American standard series for power and distribution transformers. The counterpart to IEC 60076 for ANSI/IEEE markets.
    UK Compliance & Trust Signals

    ENATS 35-1

    DNO-approved distribution transformer specification

    ENATS 35-2

    UK secondary substation transformer standard

    G99 Compliant

    Engineering Recommendation G99 grid interface

    BS EN 60076

    British Standard for power transformers

    EcoDesign Tier 2

    EU 548/2014 efficiency compliance

    Regional Overview

    Bidirectional, harmonic-tolerant step-up transformers purpose-built for UK Battery Energy Storage System (BESS) sites. 1 MVA to 100 MVA up to 132 kV — G99 grid-code compliant, designed for cyclic full-load operation in both directions and tolerant of harmonic content from grid-forming inverters. Supplied for stand-alone BESS, co-located solar + BESS and grid-services projects across the UK.

    Applications

    Where BESS Transformers Excel.

    01
    01

    UK Grid-Scale BESS

    G99-compliant BESS transformers for UK grid-scale battery storage projects across England, Scotland and Wales.

    02
    02

    UK Capacity Market BESS

    Bidirectional BESS transformers for UK Capacity Market, T-1 and T-4 auction projects providing peak capacity.

    03
    03

    UK Co-located Solar + Storage

    ENATS-compliant transformers for UK co-located solar and BESS projects on shared DNO connections.

    04
    04

    UK Frequency Response BESS

    BESS transformers for UK Dynamic Containment, Dynamic Moderation and Dynamic Regulation frequency-response projects.

    FAQ

    Frequently Asked Questions

    Deployed in

    Saudi ArabiaRiyadhSaudi ArabiaNEOMIndiaMumbai

    Related Knowledge

    FAQs, glossary terms and sizing steps mapped to this product.

    Glossary
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