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Electrical networks

Medium-term horizon

The Conceptual and Conservative case studies give no indication that the anticipated development of the electricity industry might require any substantial changes to be made in the planned development of electrical networks beyond the scope of what their operators currently envision. Changes affecting selected sources and consumption at HV and LV levels will create the need for investment at relevant locations only, no system-wide investments will be required.

In the New Technologies case study, the impact of new distributed sources operation begins to manifest as early as in the medium term; despite the decommissioning of existing sources linked to distribution networks, energy supplies from transmission to distribution systems continue decreasing along with the load levels of 110 kV networks. The requirements for sufficient capacity of the transformation link continue to apply regardless. The utilization of new distributed sources is contingent on their involvement in system operation. For expected volume of new RES installations, it is necessary to include them into system operation and control.

Long-term horizon

  • The development and future operation of electrical networks is affected by the decentralization of the electricity sector. Changes in the source base, in consumption location, in the size and shape of loading charts, in power balance and cross-border power flows, as well as changes in the implementation and utilization of accumulation produce fundamental shifts in the character of network operation and in further development requirements over the long term.
  • Development of the transmission system will be affected by the implementation of new nuclear blocks, especially in the Conservative case study. The Conceptual case study will be affected similarly by the development and structure of additional sources connected to the PS. In the New Technologies case study, the transmission system is primarily used for cross-border electricity transmissions and on securing reliable supply to distribution networks following the decommissioning of major sources.
  • In the long term, the transmission system development plan for expects gradual transition to unified voltage level of 400 kV by 2040. Strengthening of the transmission system by new 400 kV lines together with the growing share of distributed sources will result in lower loading of the power system elements. Keeping voltage within operating limits will require the installation of new compensation devices in the TS with a capacity of up to 1 300 MVAr. Total annual supply of electricity from TS to DS reaches 48 TWh in the Conceptual case study by 2030 and is similar to that in the Conservative case study. This figure is lower by 4 TWh in the New Technologies case study. In 2060, energy outflow from TS to DS is 64 TWh, while in the New Technologies case study this outflow is lower by 19 TWh and in the Conservative case study by 3 TWh.
  • Further development of the LV and HV distribution systems will be affected by the continuing increase in generation from distributed sources and by changes in the consumption structure (involving electromobility, in particular). Decentralization of the generation base will require considerable strengthening of distribution systems at lower voltage levels. The need to change organization of the operation and control method of the DS – by means of electricity accumulation and implementation of both generation and consumption management – will also be quite significant.
  • In the Conceptual and Conservative case studies, currently planned investments in networks of all voltage levels will need to be supplemented with local investments in areas experiencing greater increases in distributed sources and new offtakes. Network operation in the New Technologies is unsecured, unless significant investments with a view to developing and strengthening distribution networks are made.
  • For the integration of distributed sources to be successful, especially with regard to the New Technologies case study, the way of operating and controlling networks at all voltage levels will have to undergo substantial changes. Investment measures such as network reinforcement and accumulation construction must go hand in hand with the implementation of both consumption and generation management at the level of HV and LV networks, which are expected to take advantage of smart network technology.  Voltage and line loading in distribution systems will need to be addressed not only by strengthening system elements, but also by flexibility utilizing the regulation potential of distributed sources with respect to both voltage control and active/reactive power regulation. A properly implemented flexibility of distributed sources is necessary to ensure compliance with the required technical criteria for the safe and reliable operation of LV, HV and 110 kV networks. Given the proposed volume of new sources in the distribution networks, it will be neither technically nor economically viable to ensure that all production of these sources is released into the system at any given moment, meaning that a portion of their production will essentially remain unused.

Figure 9.1 TS line load incidence rate under non-fault conditions – 2060


Figure 9.2 TS line load incidence rate during N-1 inspections – 2060