We participate in the launch of the energy bridge Poland – Ukraine

Intensive work is already underway at the Rzeszów substation to restart the transmission over the 750 kV overhead power line built in 1985. However, this is done in a completely different way than originally assumed. Currently, the works are performed in four ways at the same time, practically on one site, with the participation of four independent entities.

• First, one set of the 750/400 kV autotransformer is dismantled and at the same time transferred to Ukraine, where it will work at the end of the 750 kV line, transforming the voltage of 400 kV to 750 kV. Thus, the 750 kV and 400 kV voltage contact will disappear from the Polish power grid, and this point will be moved to Ukraine. This scope is implemented by the Ukrainian side.
   
• Secondly, a significant part of the existing 750 kV switchgear in terms of primary circuits is being dismantled. Necessary 750 kV equipment is dismantled in order to make room for new apparatus, but already at 400 kV voltage. After the disassembly, the necessary 400 kV equipment will be mounted on the left and adapted structures, including: circuit breakers, disconnectors, current and voltage transformers, overvoltage limiters, support insulators and lower busbars. The upper splint remains unchanged. This scope is performed by an external entity based on an independent agreement.
   
• Thirdly, the telecommunication circuits, cables and equipment are dismantled, also to the extent necessary to install devices for 400 kV. After the dismantling, secondary circuits in the field of power system protection automatics and the system of controlled connection of the circuit breakers poles will be installed. General interruption recording systems, emergency signalling, tele-signal, control panels, line energy measurement systems and chokes will be adjusted or expanded, as well as the necessary accompanying works related to the commissioning of the connection of Rzeszów substation – Khmelnytskyi Nuclear Power Plant at 400 kV. In the field of telecommunications, it is planned to install telecommunication cabinets, construction of redundant fibre optic connecting cables, installation of a LAN node, installation of high-frequency devices with an integrated tele-protection section, replacement of coupling filters, blocking chokes, high-frequency cables and participation in commencement of communications.To perform the above works, it is also necessary to make an inventory of the existing circuits in order to put aside the secondary circuits, telecommunications, measurements and automatic systems intended for disassembly. Due to the necessity to operate the substation of the remaining 110 and 400 kV voltages and the complicated connections of 750 kV secondary circuits with other switchgears, for example by means of triple differential protection system or complex power system automation extending beyond the Rzeszów substation, shutdowns and selective immobilizations of the station's operating devices are quite a challenge for engineers. The one-and-a-half circuit breaker system of the existing 400 kV switchgear additionally complicates the work on putting related to disconnecting and disabling secondary circuit devices. Eltel Networks Energetyka SA will be responsible for the entire scope.
   
• Fourthly, the 750 kV choke, which is designed to be energized, will be renovated. Scope provided by Hitachi Energy. In this case, the professionalism of our company's activities in the area in the field of operation and servicing of HV transformers has been appreciated and a significant scope of works related to the renovation of 750 kV chokes will be carried out by Eltel Networks Energetyka SA.
   

Bravo! Congratulations #ZałogaEltelNetworks! #TeamEltelNetworks!
We are proud that the transmission network operator (PSE S.A.) has entrusted our company with such a strategic scope of station work for the launch of the energy corridor between Poland and Ukraine.