• Onsite circuit breaker maintenance (insulation resistance / contact resistance / mechanism)
• Full functional operational testing
• Primary current injection protection testing
• Secondary current injection protection testing
• Workshop / Rotables repairs & rebuilds
• Onsite retrofitting of breakers
• OCR relay protection upgrades / retro fitting

• Onsite circuit breaker maintenance
• Full functional operational testing including (insulation resistance / contact resistance / timing / travel measurements / AC withstand / minimum close and trip)
• SF6 filling / analysis and condition assessment
• SF6 leak detection and repairs
• Workshop / Rotables repairs & rebuilds
• Mechanism measurements and adjustments
• DC withstand vacuum bottle testing
• Oil breaker testing and assessment
• GIS testing and equipment maintenance

• Onsite switchyard circuit breaker maintenance
• Switchyard isolators and primary equipment maintenance
• Full functional operational testing including (insulation resistance / contact resistance / timing / travel measurements / dynamic resistance / spring charge time / AC withstand / DLA / minimum close and trip)
• SF6 filling / analysis and condition assessment
• SF6 leak detection and repairs
• Workshop / Rotables repairs & rebuilds
• GIS testing and equipment maintenance

• Oil streamlining / filtration services (Up to 6000 Lt /Hr )
• Oil leak and bushing repairs / replacement
• Protective instrument repairs and testing
• Radiator replacement / cooling system upgrades
• Workshop refurbishments / corrosion repairs / leaks
• Workshop refurbishments of full gasket overhauls
• AVR maintenance testing
• Oil sampling and analysis
• OLTC service by OEM trained personnel

• Insulation resistance & Polarisation Index
• Ratio and Vector group test
• Winding resistance
• Dynamic winding resistance tests for transformers fitted with OLTC
• Dielectric loss angle (DLA)
• Leakage reactance
• Sweep frequency response analysis
• Single phase excitation current
• Dielectric frequency response (DIRANA)
• CT tests
• AVR commissioning with OLTC
• Instrument calibration and testing
• Oil tests

Protection Relay Testing

HES has a large team of competent protection relay engineers and technicians to complete maintenance works in all aspects of the power industry.

• Primary plant scheme testing
• Secondary injection scheme testing
• Recloser maintenance testing
• Modification of protection setting files for relay protection
• Upgrades to IEC 61850 relay protocols and set up
• Retro fitting / upgrades of relays from electromechanical to
  newer electronic reliability
• Renewables protection scheme testing
• Power generation protection scheme testing

Earthing

Your earth grid integrity is critical to the correct functional operation of a protection system, ongoing verification of this ensures your compliance and reliability.

• Fall of potential (FOP) maintenance grid testing
• Conductivity testing
• Step and touch verification testing
• Equipotential potential rise (EPR) verification testing
• Lightning protection system testing
• Soil resistivity testing
• Current distribution testing
• Earthing system incident investigations
• Locating existing grids that have become buried over time