The paper looks at the issues of operation safety of the national power grid and the characteristics
of the national power grid in the areas of transmission and distribution. The issues of
operation safety of the national transmission and distribution grid were discussed as well as threats
to operation safety and security of the electricity supply related to these grids. Failures in the
transmission and distribution grid in 2017, caused by extreme weather conditions such as: a violent
storm at the night of 11/12.08.2017, hurricane Ksawery on 5–8.10.2017, and hurricane Grzegorz on
29–30.10.2017, the effects of which affected tens of thousands of electricity consumers and led to
significant interruptions in the supply of electricity were presented. At present, the national power
(transmission and distribution) grid does not pose a threat to the operation safety and security of
the electricity supply, and is adapted to the current typical conditions of electricity demand and the
performance of tasks during a normal state of affairs, but locally may pose threats, especially in
extreme weather conditions. A potentially high threat to the operation safety of the national power
grid is closely linked to: age, technical condition and the degree of depletion of the transmission and
distribution grids, and their high failure rate due to weather anomalies. Therefore, it is necessary
to develop and modernize the 400 and 220 kV transmission grids, cross-border interconnections,
and the 110 kV distribution grid (especially in the area of large urban agglomerations), and the MV
distribution grid (especially in rural areas). The challenges faced by the transmission and distribution
grid operators within the scope of investment and operating activities, with a view to avoiding
or at least reducing the scale of grid failures in the case of future sudden high-intensity atmospheric
phenomena, are presented.
In this paper, selected aspects of the national technical level of electric energy supply security is shown. An analysis and assessment of the electric power infrastructure in area of generation, transmission and distribution in aspects of electric energy security is conducted. The profile of the generation sector and grid infrastructure in the area of transmission and distribution is shown. The present and future situation in a range of operation of electric power infrastructure in the area of generation, transmission and distribution in the frames of the National Electric Power System in the electric energy supply security context is determined. The level of national electric energy supply security in area of generation and grid infrastructure is assessed. Threats of electric energy supply security are described and the catalogue of essential actions for the assurance of electric energy supply security are proposed. In the area of electricity generation, at present there is no danger to the electricity supply security in normal load conditions, but there is a high probability that it will occur in the future (after 2025) when the forecasted increase in electricity demand takes place and the new stringent environment protection requirements (Directive IED, BAT conclusions, Winter Package) enter into force. The network infrastructure in area of transmission and distribution is admittedly adapted for presently occurred typical conditions of electric energy demand and the realization of internal tasks in normal conditions, but can create a potential threat for electric energy supply security. In the context of the forecasted increase of electric energy demand, inadequate power generation sources in the National Electric Power System and available through intersystem connections, their uneven location on the territory of Poland in the shortage of proper network transmission capacities, the necessity of improvement of the quality and electric energy supply reliability to final consumers and the intensive development of renewable energy sources, the present network infrastructure in area of transmission and distribution will be insufficient.