20 MW solar farm electrical design.
Case study: electrical design and documentation for a 20 MW solar farm in SE Queensland — DC array layout, AC reticulation, inverter station, HV connection to the network operator and SCADA integration to AS/NZS 5033 and AS/NZS 4777.
Project overview
ASTCAD provided electrical design services for a 20 MW utility-scale solar farm in SE Queensland. Scope covered DC array layout, AC reticulation, inverter stations, HV transformer connections, the substation switchboard and the SCADA integration to the network operator’s monitoring system.
The challenge
The site straddled two soil types with different geotechnical conditions affecting pile depth. The network operator (Energex) required compliance with their specific generator-connection technical standard, and the project had to be deliverable for grid connection within a 14-month programme.
Our approach
- DC array string design optimised for inverter MPPT range
- AC reticulation with VSD-rated cable sizing
- HV transformer and switchgear design for grid connection
- SCADA integration architecture and protocol mapping
- Compliance documentation per Energex connection standard
Deliverables
- DC and AC single-line diagrams
- Array layout drawings
- Inverter station design
- HV substation drawings
- Grid connection compliance package
Outcome
The farm achieved grid connection on schedule. Energy generation has been within 2% of PVsyst-modelled values across the first year of operation. The asset owner has engaged ASTCAD for design support on a 35 MW expansion adjacent to the existing site.