APD Global delivers earthing design and testing across Australia and New Zealand - substation earth grids, BESS and renewable sites, transmission easements and the pipelines and third-party assets that share the corridor. The work sits in-house with the substation and transmission design bench, not with a subcontractor: the engineer modelling the earth grid is working from the same layout as the engineer placing the plant.
Effective earthing is one of those things you rarely notice when it's done right - and absolutely notice when it isn't. As renewable projects grow in scale and complexity, understanding how fault current behaves below the surface is critical to protecting people, assets and network performance.
The method: model to measurement
Every earthing design follows the same discipline:
- On-site soil resistivity measurement - layered soil data from the actual site, not an assumed figure.
- CDEGS modelling of the earthing system - grid impedance, earth potential rise, touch and step voltages, engineered against Australian and international standards.
- EPR, LFI and EMF assessments - earth potential rise on site, low-frequency induction onto nearby services, and electric and magnetic field exposure.
- Lightning protection - shielding and down-conductor design integrated with the earth grid.
- Pipeline and third-party assessments - transferred voltage onto pipelines, fences and telecommunications assets sharing the corridor.
- Site testing that matches the model - current injection testing on the installed grid, accepted only when measurement agrees with prediction.
Substation earthing
Every substation APD designs leaves with an earthing system designed and proven by the team that laid out the yard - from distribution zone substations through to 500 kV terminal stations. Earth grid design, gradient control, fence earthing and the interface with cable systems and overhead earthwires are engineered together with the primary layout, so earthing is never a retrofit. HV substation design →
BESS, renewables and grid connection
Storage and renewable sites bring their own earthing problems: large buried cable networks, inverter fault behaviour, public boundaries, and network operator requirements that must be satisfied before connection. APD's earthing work on battery projects - from community-scale storage through to grid-scale BESS - covers design, EPR assessment and post-installation testing as part of the same connection scope. BESS & grid connection →
Transmission and pipelines
On transmission corridors the earthing questions run the length of the easement - tower footing resistance, earthwire performance, induced voltage on parallel pipelines and fences, and the LFI limits that protect maintenance personnel on third-party assets. These assessments sit alongside the line design itself. Transmission design →
Earthing in delivered work
From zone substations to grid-scale storage.
Perth CBD zone substations
Earthing design and testing for zone substations in the Perth CBD - constrained urban sites where transferred voltages onto surrounding infrastructure drive the design.
Alkimos community battery
Earthing design and EPR testing for community-scale battery storage - the same model-to-measurement discipline at distribution scale.
Jerrabomberra Zone Substation
Full greenfield GIS zone substation for Essential Energy - earthing designed inside the same multidisciplinary model as the building and plant.
The case →Earthing - the questions asked most
Frequently asked questions.
What is earthing design?
The engineering of the buried conductor system that carries fault current safely into the ground. It sets touch and step voltages within safe limits, protects plant, and keeps protection systems operating correctly during a fault. A complete design covers soil resistivity measurement, computer modelling of the grid, EPR assessment, and site testing that verifies the installed system matches the model.
What is earth potential rise (EPR)?
The voltage the local ground reaches when fault current flows through an earthing system. High EPR can create hazardous touch and step voltages on site and can transfer onto nearby pipelines, fences and telecommunications assets. The EPR assessment drives the earth grid design, gradient control and separation requirements.
What is CDEGS modelling?
CDEGS is the industry-standard software suite for modelling earthing systems in layered soils - predicting grid impedance, EPR and touch and step voltages before anything is buried. APD verifies every model against real measurements on the installed grid.
Why does a BESS or renewable site need an earthing study?
Battery, solar and wind sites combine large fault levels, extensive buried cable networks and public boundaries. An earthing study proves the combined system keeps touch and step voltages within limits, addresses low-frequency induction on nearby services, and satisfies the network operator's connection requirements.
How is an earthing system tested after installation?
By measurement. Current injection testing energises the installed grid at a known current and measures the actual EPR and the voltages appearing on structures, fences and nearby assets. The system is accepted only when the measurements match what the model predicted. Because sometimes, the best engineering outcome is that nothing happens.