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Electrical networks

Development of the source base of the Czech power system (unit capacities, location of sources) is not the only factor to affect future operation and development of electrical networks. The effect of electricity consumption, shape of the load diagram, accumulation, power balance and the related cross-border electricity transfers might sometimes have higher effect on future form and operation of the electrical networks than the source base development.


Medium-term horizon

The Conceptual and EU – Energy Savings case study, with respect to the anticipated development of the source base, do not imply the need of considerable changes in the planned development of electrical networks as prepared and updated by the networks' operators. On the other hand, the EU – Low-Emission Sources case study, due to the anticipated increase in installed capacity of solar and wind power plants connected to low-voltage and high-voltage networks, requires significant renovation and development of these networks as soon as in the medium-term horizon especially in the areas where the new distributed sources are to be located. Local issues, particularly concerning voltage quality and line loading, will need to be dealt with not only by investment measures but also by the flexibility utilizing regulatory possibilities of distributed sources, both in the area of active and reactive power flows and also with the use of new accumulation elements. Adequately implemented flexibility ensures the fulfilment of the required technical criteria for the operation of LV, HV and 110kV networks.

Transmission system – development by 2025

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Long-term horizon

Development of the transmission system will be affected by conditions of the source base, especially by commissioning of new nuclear units and large power plants connected to the transmission system. Apart from that, operation of the transmission system is to a large degree affected by the loading of cross-border lines due to the inter-state electricity transmission. It is most of all manifested on the CZ-PL and CZ-AT cross-border profiles where the interconnection at the 220kV level is to be decommissioned without replacement by a 400kV line.

In the long-term horizon, concept of the transmission system development anticipates gradual transition to a unified voltage level of 400kV which shall be completed by 2040. Strengthening of the transmission system by new 400kV lines together with the growing share of distributed sources will result in lower loading of the power system elements, which will increase the reactive power generated by lines of the transmission and distribution systems. Maintaining voltage level within operating boundaries will require the installation of new compensation elements. The total annual electricity flow from TS to DS in 2050 is by 9TWh lower in the EU – Energy Savings case study and by 8TWh lower in the EU – Low-Emission Sources than in the Conceptual case study.

Further development of the low-voltage and high-voltage distribution systems will be affected by continuing increase in generation from distributed sources and by the change in consumption structure (electromobility etc.). It will require considerable strengthening of distribution systems at the involved voltage levels. The need to change organization of the operation and control method of the distribution system – by means of electricity accumulation and implementation of new control elements – will also be quite significant. Operability of the networks is sufficient in the Conceptual and the EU – Energy Savings case studies under the presumption that all the planned investments to networks at all voltage levels are realized. The EU – Low-Emission Sources case study requires considerable investment to development and strengthening of the distribution systems. For successful integration of the distributed sources, especially in the EU – Low-Emission Sources case study, the way of operation and control of distribution networks will have to change greatly.