A bunch of wires that are connected to a building

Power & Distribution Transformers

Transformers are the heart of every electrical system — and among the most expensive assets to replace. G&G Renewable Services provides full-lifecycle transformer support: from installation and commissioning to condition assessment, preventive and predictive maintenance, corrective repair, and end-of-life investigation. We support power transformers rated up to 750 MVA and 500 kV voltage class.

Preventive Maintenance

Dielectric oil regeneration and thermo-vacuum oil processing
Transformer drying and dehydration
Passivation and inhibitor addition
Leak correction and mechanical maintenance of accessories
Metal-mechanical repairs, surface preparation, and industrial coatings
Minor active-part repairs
Condition-based maintenance programs

Diagnostics & Condition Assessment

Comprehensive technical inspection of power and distribution transformers
Mechanical assessment of structural and containment components
Inspection, evaluation, and replacement of transformer accessories
Leak detection, localization, and corrective actions
Post-failure diagnostics and event analysis
Oil sampling for physicochemical and Dissolved Gas Analysis (DGA)
Interpretation of test results and engineering recommendations
Partial discharge analysis
Asset condition and risk evaluation

Predictive Maintenance

Asset condition monitoring programs and periodic electrical testing
Trending and analysis through DGA and physicochemical testing
Assessment of aging and degradation mechanisms
Partial discharge monitoring and analysis
Technical reporting, condition indicator tracking, and asset health assessment

Corrective Maintenance & Repairs

Dielectric oil replacement and replenishment
Leak correction, sealing, and transformer drying processes
Post-event and post-failure interventions
Repair and replacement of accessories; minor active-part repairs
Transformer disassembly, transportation, and reassembly
Emergency response and recovery support

OLTC & DETC (Tap Changer) Services

Inspection of On-Load Tap Changers (OLTC) and De-Energized Tap Changers (DETC)
Mechanical and electrical diagnostics
Preventive and corrective maintenance; component replacement
Functional adjustments, operational testing, and performance verification

Assembly, Installation & Commissioning

Assembly and installation of new or refurbished transformers
Installation of radiators, bushings, conservators, cooling systems, and accessories
Vacuum processing and vacuum oil filling
Electromechanical assembly supervision
Pre-energization testing and functional verification of accessories
Energization, commissioning, and Site Acceptance Testing (SAT) support