Substation Maintenance and Commissioning Services

We implement the latest developments in HV and MV substation maintenance services and we use state of the art diagnostic tools to detect defects in very early stages, providing adequate time to our customers for decision making, before the fault occurs. We aim to minimize the number of undesired outages and maximize the effective operation time of our customers’ installation.

Detailed off-line diagnostic measurements as well as on-line monitoring tools provide reliable information, allowing us to aqurately detect the beginning of insulation or windings deterioration in MV and HV installations. Based on this information, we suggest to our customer available measures to minimize the damage.
We follow the international practices and standards to create efficient maintenance schedules, tailored to our customers needs.
We have a long-term experience in commissioning, as well as time-based or condition-based maintenance works on 20kV-33kV-150kV industrial or renewable energy substations and 400kV installations.

Our services include:

  • HV and MV power transformer diagnostic measurements acc. to IEC 60076 (Ratio – Winding Resistance – Insulation Resistance – Excitation Current – tan d – Short-Circuit impedance – SFRA – DFRA).
  • Measurements on HV and MV Current and Voltage measuring transformers (Ratio – Winding resistance – Knee point – Burden).
  • Measurements on HV and MV Circuit Breakers (Time test – Contact Resistance – Insulation Resistance).
  • Measurements on protection relays.
  • HV or MV power transformer Bushing replacement.
  • HV or MV power transformer OLTC maintenance
  • MV panels maintenance (cleaning, primary – secondary injection, measurements on CTs – VTs, protection relay testing, etc.)
  • Complete Commissioning services on 150kV/20kV Substations, 20/150kV or 33/150kV Renewable Energy Step-Up Substations and 400kV installations.
  • Detailed Wiring tests to verify electrical drawings and auxiliary circuits.
  • Detailed Functional tests
  • Comprehensive reporting
  • Compliance verification of the technical specifications of the installed equipment with the technical specs of the study.
  • Thermal imaging services of installations under load to detect hot spots.
Συντηρήση υποσταθμών

Additionaly we offer:

  • Radio Frequency Interference (RFI) on-line surveys on Air Insulated Substations.
  • Electromagnetic interference (EMI) on-line measurements on Power Transformers, Motors and Generators.
  • On-line Partial Discharge measurements on Power Transformers, Motors and Generators.
  • Power quality continuous recording according to ΕΝ 50160 and Class A / IEC 61000-4-30 requirements.
  • RMS Power quality transient recording with 10 msec recording rate and Fast Transients oscillographic recording with 10 MHz recording rate.
  • Measurement of Grounding systems in MV and HV Subtations, Wind Generators, Solar and industrial installations (Grounding Resistance, Step volages, Touch voltages and Metal-to-Metal voltages).
  • Measurement of Soil Resistivity according to the Wenner method.
  • Ground loop continuity tests.
  • Line Impedance measurements.