Instilling optimal reliability

Rayo provides trusted operations and maintenance services for Australia’s high voltage infrastructure — supporting transmission and distribution networks, renewable generation assets, and large-scale industrial and mining facilities.

We exist to keep critical assets performing safely, efficiently, and predictably. Our programs are structured to reduce outage risk, optimise asset life, and give asset owners complete confidence in their network performance.

Our delivery teams bring decades of experience managing the operation, inspection, and maintenance of complex substation and generation systems across the national grid. With Rayo, clients gain the agility of a specialist contractor backed by the discipline and systems built by Tier 1-experienced leadership.

Primary plant maintenance

Inspection, maintenance, repair and testing of oil and SF₆ circuit breakers, including timing analysis, contact resistance, insulation resistance, gas and oil analysis, and mechanical testing.
Maintenance and condition assessment of instrument transformers (CTs and VTs).
Inspection and servicing of isolators and earth switches, including operational testing and contact alignment.
Replacement and performance verification of surge arresters and earthing systems.
Full-scope transformer maintenance, oil sampling and filtration, bushing testing, and condition monitoring.
On-load tap changer (OLTC) inspection, contact wear assessment, oil filtration, and functional testing.
Secondary systems and protection testing, calibration and verification of protection relays — electromechanical, static and numerical.
Secondary injection, end-to-end scheme testing, and trip/intertrip verification. SCADA and control system testing, point-to-point checks, and functional integration

Operations and switching

Provision of authorised HV operators to conduct network switching and isolations under formal access systems.
Development of switching schedules and isolation procedures, tailored to client frameworks.
Support for planned outages, energisation, and commissioning.

Inspection and reliability

Balance of Plant inspections for renewable assets, including mechanical, electrical and civil condition assessments.
Thermographic surveys, oil analysis coordination, and asset health reporting.
Implementation of condition-based maintenance programs to predict failure and extend service life.

Testing and commissioning

Comprehensive HV and LV testing across Doble and Omicron testing platforms — insulation, winding resistance, CT/VT ratio, contact resistance, tan delta, SFRA, and more.
Functional and performance testing of primary and secondary equipment prior to energisation.
Integration of OEM test procedures into structured Inspection & Test Plans (ITPs) for full traceability.