GPZ Stations

Periodic Inspections of GPZ Stations

GPZ stations are a crucial element of the electrical power network. To ensure their proper operation and avoid serious failures in the future, it is necessary to periodically check their technical condition. We offer a wide range of services related to periodic inspections and measurements of GPZ stations:

  • Measurement of the resistance of transformer and reactor windings
  • Testing of self-times, simultaneous switching of tap changers
  • Measurement of self-times of high voltage circuit breakers
  • Measurement of contact resistance of circuit breakers and disconnectors
  • Measurement of current and voltage transformers, determination of magnetization characteristics, checking the class and actual ratio
  • Measurement of step voltages and touch voltages
  • Measurement of insulation resistance of transformers, cables, switchgears
  • Measurement of the resistance of main current path connections
  • Inspection of medium voltage switchgears in air and SF6 insulation
  • Checking SF6 gas leakage
  • SF6 gas analysis
  • Voltage tests of MV cables using both DC and VLF injectors with PD measurements
  • Measurement of the capacitance of guaranteed voltage batteries
  • Thermographic inspection of main current path connections
  • Partial discharge testing
  • Testing of 110kV and MV protections

Maintenance of GPZ Stations (Daily Operator)

Our offer includes comprehensive maintenance of electrical substations (GPZ). We provide:

  • 24/7 supervision of the GPZ station
  • Performing switching operations
  • Periodic inspections
  • Fault elimination

We ensure the uninterrupted operation of the station, minimizing the risk of downtime and failures.


Inspection with a thermal imaging camera enables quick, non-invasive examination of the condition of connections on busbars, switchgears, and electrical devices without the need to disconnect them from the power supply.

Partial Discharge Testing Using Acoustic Method

Partial discharge testing using the acoustic method allows for the diagnosis of faults in 110kV equipment and medium voltage switchgears, both air-insulated and SF6, before they cause serious damage and station downtime. These tests enable us to plan maintenance work, prioritizing repairs where they are most needed.

GPZ Station Projects

If you are planning to connect a wind turbine to the grid, modernize, or build a GPZ station, our designers will provide a professional project and support during construction.

Modernization of Medium Voltage Fields

Connecting generating sources, such as wind turbines, to existing GPZ stations requires the modernization of medium voltage field connections and the adjustment of protections to a bidirectional mode. We offer a full range of services related to modernization:

  • Design of the modernized field or part of the station
  • Execution of the current-carrying part, laying of cables, installation of cable terminations, and post-installation tests
  • Implementation of secondary circuits, equipping cabinets, installation of new protections, and their configuration according to the designed settings

Setting Changes, Configuration, and Protection Testing

In the case of transmission network reconfiguration or station modernization, it is necessary to adjust the protection settings to the new network conditions. We offer services for changing protection settings, configuring new protections (Micom, Siemens, ABB), re-configuring, and testing the accuracy of existing protection settings using Kocos Artes 560 and UTC-GT testers.