From diagnosis to return to service
When routine maintenance is no longer sufficient, COMMI carries out the overhaul, refurbishment and revamping of high-voltage equipment installed in electrical stations and substations, at its workshop in Osio Sopra or directly at the client’s installation.
Revamping is carried out on existing equipment by replacing obsolete or no-longer-available components, such as valves, operating mechanism parts and accessories, with equivalent solutions, keeping the equipment in operation without replacing it.
The aim is to restore the equipment to the conditions required for operation, with checks and testing before return to service.
A Complete Process
Diagnosis → Dismantling → Inspection → Overhaul → Refurbishment → Reassembly → Testing → Service
Each stage is carried out in accordance with the applicable procedures and recorded. On completion, the equipment undergoes the specified checks and testing before return to service.
The Equipment
High-Voltage Circuit Breakers
Equipment inspection, maintenance of operating mechanisms and electromechanical accessories, adjustments, instrumental checks and measurements, and testing.
High-Voltage Disconnectors
Inspection of insulators, contacts and connections, maintenance of linkages, operating mechanisms and drives, lubrication, checks of operating sequences and interlocks, and functional and instrumental checks.
Current and Voltage Transformers — CTs / VTs
Equipment inspection, cleaning of insulating parts, verification of connections and accessories, checks and measurements according to the equipment design and configuration.
Surge Arresters
Inspection of insulators and connections, cleaning of insulating parts, check of the surge counter, where fitted, and the checks required by the project.
Power Transformers
Inspection of the transformer and its accessories, verification of protection and signalling devices, electrical measurements, functional checks and tests. Oil sampling and treatment, where required, in cooperation with specialised partners.
Operating Mechanisms and Auxiliary Circuits
Inspection of operating mechanisms, signalling, interlocks and auxiliary circuits, with functional checks.
High-Voltage Circuit Breaker Overhaul
COMMI specialises in the overhaul of HV circuit breakers manufactured by the former Nuova Magrini Galileo, up to 420 kV, with procedures defined for each circuit breaker type and overhaul kits held in stock. It also overhauls opening and closing valves.
Depending on the condition of the equipment, the work is carried out on site, during the outage, or in the workshop, with dismantling of components, replacement of wear parts, reassembly, adjustments and tests.
On Site | In the Workshop
Exchange Poles to Reduce Downtime
Where technically compatible with the equipment, COMMI can supply overhauled and tested exchange poles to replace the existing poles during the overhaul.
The poles removed from the installation are taken over by COMMI, overhauled and refurbished for future use.
Availability and applicability are assessed in advance, according to the equipment and the requirements of the installation.
Overhaul and Restoration: Before and After
HV Circuit Breakers – Before / After
Power transformer – before / during / after
On-site surface restoration
Tests Before Return to Service
Depending on the equipment and the project requirements, final tests may include:
Opening / Closing (Trip / Close)
Operating Times
Pole Synchronism
Insulation Resistance
Contact Resistance
Control Circuits
Signalling
Alarms and Lockouts
Gas Tightness / Pressure
Final Testing
Let's Assess Your Overhaul Requirements
For an overhaul on site or in the workshop, we assess the condition of the equipment and determine the most suitable approach for the project.