LV, MV and HV Switchgear

HES has a well constructed Workshop with specialised and highly skilled technicians to service and repair LV, MV and HV Switchgear. HES offers services in the following:

Switchgear Services

Low Voltage:

  • Workshop circuit breaker maintenance
  • Full functional operational testing (insulation resistance / contact resistance / mechanism)
  • Primary current injection protection testing
  • Secondary current injection protection testing
  • Workshop / Rotables repairs & rebuilds
  • OCR relay protection upgrades / retro-fitting
 Medium Voltage:

  • Workshop 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
 High Voltage:

  • Workshop 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 /measurement and condition assessment
  • SF6 leak detection and repairs
  • Workshop / Rotables repairs & rebuilds
  • GIS testing and equipment maintenance

SF6 Handling

HES has a well constructed workshop with highly skilled specialists and technicians to provide SF6 gas analysis, leak detection and handling. HES offers services in the following:

  • SF6 leak detection using Wika sniffer and FLIR Camera
  • SF6 leak repairs to switchgear
  • SF6 pressure gauge replacement
  • SF6 gas analysis
  • SF6 handling using Dilo Cart

Transformers

HES has a well constructed workshop with highly skilled specialists and technicians to assemble, service and repair oil filled transformers. HES offers services in the following:

Maintenance & Repairs:

  • 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
  • Refurbishments / corrosion and rust repairs
  • Full gasket overhauls
  • AVR maintenance testing
  • Oil sampling and analysis
  • OLTC service by OEM trained personnel
  • Transport skid and bunded bag for correct storage
 Testing:

  • 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 sampling / tests

Spare Parts:

  • Dehydrating breathers
  • Oil and winding temperature indicators
  • Pressure relief devices
  • Gaskets – pre-cut, sheet or roll
  • Bushings and adaptor flanges
  • Fans, pumps and related controls
  • Control cubicles
  • Radiators, heat exchangers and header assemblies

  • Buchholz gas/surge relays and ground level receivers
  • Naphthenic mineral oil or high fire point environmental fluid
  • Anti-vibration pads for mounting underneath transformers
  • On and off load tap changer parts
  • On-line monitoring devices such as for bushing DLA & capacitance, transformer partial discharge, moisture, oil quality & DGA
  • Any other specific requirement from our customers

Panel / Protection Upgrades

HES has a well constructed Workshop with highly skilled technicians to provide relay panel upgrades and panel commissioning. HES offers services in the following:

  • Relay panel wiring modification
  • Relay panel commissioning / FAT testing
  • Retro-fitting / upgrades of relays from electromechanical to newer electronic reliability
  • Modification of protection setting files for relay protection