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Electrical networks

Development and future operation of electrical networks mainly affected by changes in source base, electricity consumption, shape of the load diagram, utilization of accumulation, power balance and the resulting cross-border electricity exchanges. Length of new transmission system lines by 2050 is shown in the following table.

Length of new transmission system lines by 2050 (km)

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Mid-term horizon

  • The Conceptual and Gas case studies do not indicate any substantial changes to be made in the planned development of electrical networks on top of that currently being prepared by their operators.
  • By contrast, the Renewable case study requires significant modification and reinforcement of distribution networks at all levels as early as in the mid-term horizon due to the anticipated increase in installed capacity of distributed sources connected to LV and HV grids. Voltage within grids and line loading in distribution systems will need to be addressed not only by investments in the networks, but also by utilizing the regulation potential of distributed sources with respect to both active and reactive power and using new accumulation elements as well. A properly implemented flexibility measures are necessary to ensure compliance with the required technical criteria for the operation of LV, HV and 110 kV networks.

 

Long-term horizon

  • Development of the transmission system will be affected by the development of the source base, especially in case of commissioning of new large nuclear and units in the Conceptual case study. Apart from that, operation of the transmission system is to a large degree affected by the flows on cross-border lines due to the inter-state power transmission. It mostly manifests on the CZ-PL and CZ-AT cross-border profiles where 220 kV cross-border lines are to be cancelled.
  • In the long-term horizon, the plan for development of the transmission system anticipates gradual transition to a 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 the 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 46 TWh in the Conceptual case study in 2025. In 2050, electricity transfer from TS to DS is 58 TWh, while this outflow is lower by 37 TWh in the Renewable case study and by 8 TWh in the Gas case study.
  • Further development of the LV and HV distribution systems will be affected by continuing increase in generation from distributed sources and by changes in consumption structure (involving electromobility, in particular). It will require considerable strengthening of distribution systems at lower voltage levels. The need to change of the operation and control method of the DS – by means of electricity accumulation and implementation of new means of control – will also be quite significant.
  • In the Conceptual and Gas case studies, the currently planned investments are sufficient to ensure system operation at all voltage levels. The Renewable case study is inoperable without major investments in the development and reinforcement of the DS. For the integration of distributed sources to be successful, especially with regard to the Renewable 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.