Case study

Mornington BESS: 33kV Switchgear and End-to-End Commissioning

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Megavar testing and commissioning team on site at the 240MW Mornington BESS, Victoria

Technicians Performing High Voltage (HV) Substation Commissioning Inside a Control Room

240 MW Power

480 MWh Energy

Mornington Peninsula, Victoria Location

ACLE Services Pty Ltd Client

2025 Completion

Client: ACLE Services Pty Ltd
Principal Contractor: ACLE Services Pty Ltd
Developer: Maoneng / GMR joint venture with Gaw Capital Partners (original)
Asset Owner: Valent Energy
Location: Mornington Peninsula, Victoria, VIC
Grid Connection: AusNet Tyabb Terminal Station
Capacity: 240 MW / 480 MWh
Voltage: 33 kV
Battery OEM: Genesis TD
PCS-side Switchgear: Ormazabal with ABB REJ603 protection relays
Asset Type: Utility-scale BESS – 33kV ABB GIS, 2 switchboards
Project Type: BESS commissioning – FAT, SAT, protection, SCADA, PCS, battery discharge
Duration: Commissioning complete 2025
Megavar Scope: T&C lead for FAT, SAT, protection, SCADA and battery discharge

Technician Inspecting Equipment During High Voltage (HV) Substation Commissioning

Overview

The Mornington BESS is a 240MW / 480MWh utility-scale battery energy storage system on Victoria’s Mornington Peninsula, connected to the national grid at AusNet’s Tyabb Terminal Station. Asset owner Valent Energy (originally a Maoneng / GMR joint venture with Gaw Capital Partners) engaged ACLE Services as EPC, and ACLE contracted Megavar to deliver the testing and commissioning programme across the high-voltage and battery systems.

Megavar’s scope covered factory and site acceptance testing of the 33kV ABB GIS switchgear, HV substation commissioning of the protection and SCADA, PCS primary and secondary commissioning, field transformer testing, battery discharge testing and end-to-end integration to the AusNet grid. At peak delivery the Megavar team fielded 7 to 8 testers and engineers on site.

A significant portion of the HV testing was witnessed by the Victorian Electrical Safety Inspector to confirm testing was performed safely and to the relevant standards. The project energised successfully and is now in commercial operation.

Scope of Work

Factory Acceptance Testing (FAT)

33kV ABB GIS switchgear FAT at SRS Power, including withstand, circuit breaker timing and timing curve verification, CT ratio and polarity, earth switch operation and interlock proving
Relay FAT testing on the assembled switchboards

Site Acceptance Testing (SAT) and Primary Plant Commissioning

33kV ABB GIS switchgear SAT following site installation
PCS RMU testing: withstand, circuit breaker, CT, earth switch, interlocks and ABB REJ603 relay function checks across each PCS enclosure
PCS transformer testing using Omicron CPC 100 and Testrano 600
Field transformer testing across the wider BESS LV distribution
LV distribution and breaker testing

Protection and Secondary Systems

33kV switchboard protection setting audit across both switchboards
PCS secondary protection testing and functional checks
PQM (power quality metering) device testing
Relay typicals and logic verification against the issued protection scheme

SCADA and Integration

DNP3 map verification and rebuild across the 33kV protection relays
Typicals testing to an external RTU prior to full SCADA testing
End-to-end SCADA and alarm point testing through to the
AusNet integration boundary

Battery System

Battery discharge testing through multiple phases, supporting commissioning and grid compliance

Test Equipment Deployed on Site

Omicron CMC 356: Protection relay testing and secondary injection
Omicron CMC 500: Protection and system-level testing
Omicron CPC 100: Primary injection, transformer testing, earth testing
Omicron Testrano 600: Three-phase transformer testing
Omicron Cibano: Circuit breaker timing and dynamic analysis
Omicron CMLIB REF6xx: sensor-relay interface for testing ABB REF6xx relays with the CMC
Omicron CT Analyzer: CT ratio, polarity and saturation testing
Megger Torkel 930: Battery bank discharge testing
Megger MIT 515 (5kV): Insulation resistance testing
Megger MOM2: Circuit breaker contact resistance
Megger DLRO 100: Low resistance ohmmeter testing
Phenix BK130: 130 kV AC withstand (hipot) testing
Fluke 189: General multimeter and verification

Megavar deployed a full Omicron test suite supported by Megger and Fluke instrumentation. Most of the instruments listed are available for hire from Megavar’s rental fleet.

New ABB UniGear ZS1 11 kV switchgear in service at Chapel Street Substation, commissioned by Megavar

Challenges and Approach

No DC supply on site for 33kV switchgear testing

When Megavar mobilised to the manufacturing site and then to the SAT site, no DC supply was available to power the two 33kV ABB GIS switchboards for testing. Under the Principal Tester’s direction, Megavar’s project manager sourced and purchased a DC power supply rated to power both switchboards, together with additional HV cable termination caps to prevent flashover and equipment damage during withstand testing. Testing resumed the same day, with no impact on the commissioning programme.

Incomplete ABB relay configuration and DNP3 mapping

The 33kV protection relays were delivered with typical configurations only. DNP3 point mapping was not complete from the OEM. During FAT, the incomplete relay settings were sent back to ABB to configure the DNP maps, which the end user then uploaded post-FAT. On upload, all relays went into alarm, creating an immediate integration issue with AusNet and the project SCADA.

Megavar mobilised back to site after hours, rebuilt the DNP mapping into the correct relay configuration files, and assisted ACLE to test the typicals into an external RTU before proceeding with full SCADA testing. This recovered the schedule and avoided a re-FAT of the relay panels.

PCS commissioning efficiency across a large site

The BESS layout required the test team to move between many PCS units across a large footprint. Rather than run extension leads and relocate test gear at every PCS, Megavar set up a mobile testing rig on the back of a UTE, powered by alternative power supplies (inverters). The UTE acted as an additional barricade alongside the standard delineation and reduced manual handling, trip hazards, noise exposure and mobilisation time between PCS units.

During PCS testing the team identified and flagged several faulty live line indicators, and one RMU with a circuit breaker that failed to open. These defects were raised with ACLE and rectified before the RMUs were placed into service.

Outcomes

Mornington BESS energised and entered commercial operation on programme despite the mid-project relay configuration and DC supply issues.

Every phase of HV testing that required inspector oversight was witnessed by the Victorian Electrical Safety Inspector.
Defects identified by Megavar during PCS testing (faulty live line indicators, failed RMU breaker) were corrected prior to energisation, avoiding post-energisation rework.

DNP3 mapping across both 33kV switchboards was rebuilt and verified against the external RTU, allowing clean handover to the AusNet interface.

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Megavar engineer FAT testing a Siemens 7SJ82 feeder protection relay for Chapel Street 11 kV switchgear

FAQ

Frequently Asked Questions

What does BESS commissioning involve?

BESS commissioning is the end-to-end process of proving a battery energy storage system is safe, compliant and ready to operate on the grid. It covers factory and site acceptance testing of the HV switchgear, protection and SCADA verification, PCS commissioning, transformer testing, battery charge and discharge testing, and integration testing to the transmission or distribution network. On a 240MW project, commissioning typically runs in parallel with construction for several months and culminates in a controlled first-time energisation sequence.

What is 33kV switchgear FAT and SAT testing?

FAT (Factory Acceptance Testing) is the formal testing of switchgear at the manufacturer’s premises before it leaves the factory, confirming that the product meets specification. SAT (Site Acceptance Testing) repeats and extends that verification once the switchgear has been installed on site. On Mornington BESS, Megavar carried out both FAT (at SRS Power) and SAT on the 33kV ABB GIS switchboards, covering withstand, breaker timing, CT and earth switch operation, and protection relay function checks.

How does Megavar commission battery energy storage systems?

Megavar commissions BESS installations as a single T&C work package, covering HV switchgear, protection, SCADA, PCS, transformers and battery discharge testing under one team. Our engineers and testers work from FAT at the OEM factory through to SAT, energisation and grid integration, with a preference for Omicron instrumentation (CMC 356, CPC 100, Testrano 600, Cibano) and Megger battery test sets (Torkel 930). We have delivered BESS commissioning for ACLE Services across the Mornington Peninsula and Greater Shepparton in Victoria.

What test equipment did Megavar deploy on the Mornington BESS?

On Mornington BESS, Megavar deployed a full Omicron test suite including the CMC 356, CMC 500, CPC 100, Testrano 600, Cibano, CMLIB REF and CT Analyzer, supported by a Megger Torkel 930 for battery discharge, MIT 515 for insulation testing, MOM2 and DLRO 100 for breaker contact resistance, a Phenix BK130 for AC withstand testing and a Fluke 189 for general verification. Most of the instruments listed are available for hire from Megavar’s rental fleet.

Why does DNP3 mapping matter for BESS protection?

DNP3 is the communications protocol used to exchange protection, control and alarm data between substation relays and the grid operator’s SCADA. If the DNP3 map in the relay does not match the SCADA master, the relay can flag every mismatched point as an alarm at startup, which can block integration with the transmission network. On Mornington BESS, Megavar rebuilt the DNP3 mapping across both 33kV switchboards after hours, which recovered the SCADA integration schedule with AusNet.

Where is the Mornington BESS located?

The Mornington BESS is on the Mornington Peninsula in Victoria, adjacent to AusNet’s Tyabb Terminal Station. The 240MW / 480MWh facility connects into the national grid at Tyabb and provides frequency, capacity and arbitrage services to the National Electricity Market.

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