MVA provides specialized field services for extra-high-voltage (EHV) transformers operating above 230 kV and up to 765 kV. These critical assets require experienced technicians, careful planning and precise execution. Our crews support utilities, power generation facilities and electrical service providers with the expertise needed to safely install, maintain, diagnose and repair high-voltage transformer equipment.
Experienced Support for Critical EHV Transformers
EHV transformers are essential to the reliable transmission of electricity across the power grid. Because these transformers handle substantial electrical loads, developing problems can lead to significant operational disruptions, extensive repairs and unplanned outages.
MVA’s field service teams have experience working on some of the largest and most complex transformers in the industry, including units rated up to 765 kV and 1,000 MVA. We provide comprehensive support throughout the transformer’s service life, from initial assembly and commissioning to diagnostic testing, maintenance and emergency repairs.
EHV Transformer Assembly and Installation
Proper transformer assembly and installation are critical to the long-term performance of an EHV transformer. MVA provides experienced field crews to support complete transformer assembly, vacuum filling and commissioning.
Our EHV installation services can include:
- Transformer assembly and component installation
- Bushing installation and replacement
- Conservator and cooling-system assembly
- Pump, fan and radiator installation
- Internal inspections
- Vacuum processing and filling
- Oil degasification and processing
- Electrical commissioning tests
- Final inspections and leak checks
Every project is carefully coordinated to meet the equipment manufacturer’s requirements, site-specific procedures and applicable safety standards.
Electrical Diagnostic Testing
MVA performs on-site electrical diagnostic testing to evaluate transformer condition, investigate suspected problems and establish baseline information following installation or repair. Our technicians use specialized testing equipment and proven procedures to help identify electrical, mechanical and insulation-related concerns.
Available testing services include:
- Sweep Frequency Response Analysis (SFRA)
- Transformer Turns Ratio (TTR)
- Power factor testing
- Excitation current testing
- Winding resistance testing
- Insulation resistance testing
- Current transformer testing
- Additional diagnostic testing based on the transformer and project requirements
Test results are reviewed to help asset owners determine the appropriate next steps for commissioning, maintenance or repair.
EHV Transformer Maintenance and Repair
When an EHV transformer develops a leak, component problem or abnormal test result, MVA can investigate the issue and perform the necessary field repairs. Our ability to support both diagnostics and repair helps streamline the process and reduces the need to coordinate multiple contractors.
Our repair and maintenance capabilities include:
- Transformer leak investigation, detection and repair
- Regasketing
- Bushing replacement
- Current transformer replacement
- Pump and component replacement
- Load tap changer inspection, repair, retrofit and replacement
- Vacuum dehydration and dry-out
- Oil degasification and processing
- Hot oil reclamation
- Fluid retrofilling
- Internal inspections and corrective repairs
Our teams develop a project-specific work plan based on the transformer’s condition, design, operating history and service requirements.
Transformer Oil Testing and Diagnostic Support
EHV transformer service is strengthened by MVA’s in-house transformer oil testing and diagnostic laboratory. Laboratory analysis can identify developing faults, evaluate fluid condition and provide insight into the health of the transformer’s insulation system.
Testing may include dissolved gas analysis, moisture analysis, dielectric strength, acidity, interfacial tension, power factor, furan analysis, particle count and fault metals. MVA’s experts interpret the results and provide actionable recommendations to help guide maintenance and repair decisions.
By combining laboratory diagnostics with experienced field services, MVA provides one team to identify potential issues, diagnose existing problems and complete the work needed to help prevent unplanned outages.
Nationwide EHV Transformer Field Services
MVA provides EHV transformer services at substations and power facilities throughout the United States. Whether the project involves a planned installation, scheduled maintenance, diagnostic investigation or an urgent repair, our teams are prepared to support critical transformer assets safely and efficiently.
Contact MVA to discuss your upcoming EHV transformer project or request a quote for field services on transformers operating above 230 kV and up to 765 kV.
