The Narrabeen Substation Control building houses the live electrical switchgear and equipment that control the adjacent substation. As part of the upgrade of ageing assets, Multiworks was engaged directly by Ausgrid as Principal Contractor to replace the existing roof while maintaining the live operations of the substation and the electrical network. The works included: replacement of roof tiles with Colorbond sheets, installation of CFC sheets, replacement of gutters, installation of new downpipes, installation of earthing spires and installation of new anchor points.
Prior to commencement of the roof replacement works the Narrabeen Control Building was impacted by a storm causing leakage inside the Switch-rooms. Ausgrid engaged Multiworks to execute emergency works to stop the leakage. This required the roof replacement works to be brought forward and delivered within a significantly constrained time frame.
Multiworks effectively mobilised a skilled team including additional resources from interstate. Due to the poor condition of the existing roof, Multiworks made the entire control room building watertight through implementing anchor points and tarping. This provided a temporary shield around the whole building, eliminated any impacts due to poor weather and ensured the ongoing operation of the control room.
Multiworks delivered the project one month ahead of schedule, while also completing the Castle Cove Substation works.
Services: Asbestos & Environmental Remediation
Castle Cove Control Building Roof Replacement
Multiworks was responsible for the replacement of roof metal sheets with Colorbond sheets, replacement of gutters, installation of new downpipes, construction of stormwater inlets and installation of new anchor points. Multiworks delivered all scope while ensuring the ongoing operations of the live electrical substation.
A key challenge in the roof replacement works involved implementing appropriate physical protection over the existing Frequency Injection Units (FIUs). Due to the sensitivity of the assets and client requirement that only one FIU could be de-energised at a time, Multiworks developed and implemented a staged works program over the FIUs. Multiworks effectively planned and scheduled materials and resources to ensure protection over the unit while replacing the section of roof directly above. The protection was then stripped so that the FIUs could be re-energised.
Additionally, Multiworks developed an innovative ‘Rolling Scaffold’ within the substation that offered fall protection and acted as a physical barrier to ensure the substation equipment was not exposed to falling objects.
Chullora Control Building Roof Replacement
The Chullora Substation Control building houses the live electrical switchgear and equipment that controls the adjacent substation. As part of the upgrade of ageing assets, Multiworks was engaged as Principal Contractor directly by Ausgrid to replace the existing roof without any interruptions to the electricity network.
Works took place on the existing live control building, housing equipment for this 66kV Substation. Key scope involved ACM eave replacement, removal of roof tiles, installation of two layers of Compressed Fibre Cement sheets, installation of Colorbond sheets, reinstating existing gutters, installation of new downpipes and installation of new anchor points.
During the preliminary planning, it was noted that the height from the pitch of the roof to the soffit was greater than 0.8m. Due to the substantial height difference the existing anchor points could not be used as a means of fall arrest. As a result, Multiworks proposed and successfully implemented a construction methodology that provided a means of fall arrest utilising anchor wraps. The project achieved zero safety incidents.
Lilydale Substation REFCL
The Victorian Government has mandated the rollout of Rapid Earth Fault Current Limiter (REFCL) installations across nominated Zone Substations in AusNet Services’ network, including at the Lilydale Zone Substation. Installation works included:
- Two new REFCL(s) units in bunds and footings
- Two new 22kV switched neutral bus kiosks onto new footings
- A new REFCL Room on to new pad footings to house associated inverters and control equipment
- A new modular Control Room onto new striped footings
- A new cable trench (600mm Wide x 600mm Deep) running north west to south east for associated control cables Conduits for control cables
- Associated reinstatement and surfacing
Replacement works involved:
- The existing NER with one new NER onto new pad footing
- Existing station service transformers (SSTx) with two new 750 kVA kiosk type units onto new pad footings and AC changeover boards
- Both existing Capacitor Banks with Metal enclosed Cap Banks with pad footings for REFCL compliance.
Pit Repair – Richmond Terrace
Multiworks were engaged by Citipower/ Powercor to excavate and construct a new in-ground electrical cabling pit at Richmond Terrace. Work included;
- Excavate around pit and expose existing 66kV feeder cables – 3 x cable joints
- Demolish existing pit and install new precast cable pit
- Backfill excavation and reinstate road
Pit Repair – Exhibition Street
As part of an ongoing maintenance program Citipower/Powercor is upgrading and structurally reinforcing many of its underground cable pits within Melbourne’s CBD.
Multiworks was engaged by Citipower/ Powercor to rectify the Exhibition Street pit following cracking and subsidence to its lid.
Upgrade works were complex due to the pit’s location within high density areas, their confined size and pre-existing structural issues.
The works were staged during shutdowns and involved crews operating 24 hours per day to access, reinforce and reinstall pit lids over a weekend period.
Multiworks’ effective collaboration with key stakeholders and Citipower/Powercor ensured the works were completed over the planned weekend shutdown period.
ARMCO Pipe Bridge Relining
Multworks worked with V/Line as principal contractor to carry out ARMCO pipe upgrade works as part of their essential maintenance program across the network. The work involved the relining of the bottom half of ARMCO culverts with concrete to assist in maintenance and reduce corrosion.
The works were carried out in close consultation with V/Line and local council to ensure nil safety or environmental incidents occurred.
Noble Park Zone Substation
Following the award of the Mentone Zone Substation Multiworks secured the delivery of refurbishment works at the Noble Park Zone Substation. The similarities between the two projects enabled Multiworks to capitalise on available economies of scale and to resource both jobs efficiently. The project works included:
- Construction of a 22kV Control Room
- Significant infrastructure works
- Considerable installation of conduit runs
- Resurfacing & reinstatement of roadway.
Toll Chemicals
Working within Toll’s primary chemical storage facility in Laverton, Multiworks were required to excavate and replace over 3000 m2 of engineered concrete paving. The site was to remain functional at all times and as such the works were broken into 3 stages. Straddle cranes, forklifts and delivery trucks frequent the site and hence interruptions to the sites operations were to be minimised as much as possible.
Multiworks worked closely with both Toll and Goodman to achieve an acceptable staging of works that minimised the impact on site operations and also returned the facility to full capacity as soon as possible. The project’s scope included:
- Saw-cutting, excavation and removal of redundant concrete.
- Testing of groundwater and soil.
- Engineering and sign-off of reinforcement design.
- New engineered concrete paving, approximately 3000m2
- Saw cutting of construction joints and corking.
- 3 Stages of work.
- Concrete testing.
- Reinstatement of line-marking and bollards.
Mentone Zone Substation
The Mentone Substation is situated on a site with significant space constraints. Multiworks successfully managed refurbishment works, including:
- Construction of a 22 kV Control Room including a cable basement
- Major upgrades to existing site buildings
- Construction of a 220kV transformer enclosure
- Over 700 lineal meters of trenching and conduit installation
- Installation of an environmental drainage system.