  English: Solar eruptive events affect the close neighbourhood of the Earth.
They also affect human infrastructure, power grids mainly, due to the induction
of electrical currents. Only recently the attention was drawn not only to large
flares, but also to estimate the long-term effects of increased solar activity
by statistical methods. We analyse the failure rates in the main Czech power
transmission system operated by the Czech national operator \v{C}EPS. We show
that the effects of solar activity on failure rate in the main Czech power grid
cannot be excluded even for central-european country. This is a preliminary
study.
  Czech: Eruptivn\'i projevy slune\v{c}n\'i aktivity ovliv\v{n}uj\'i
bezprost\v{r}edn\'i kosmick\'e okol\'i na\v{s}\'i Zem\v{e} a postihuj\'i
prost\v{r}ednictv\'im indukce elektrick\'ych proud\r{u} i pozemskou
infrastrukturu, zejm\'ena rozvodn\'e s\'it\v{e} silov\'e elekt\v{r}iny. Teprve
v posledn\'ich letech byla v\v{e}nov\'ana pozornost nejen hodnocen\'i
bezprost\v{r}edn\'ich dopad\r{u} siln\'ych eruptivn\'ich ud\'alost\'i na
za\v{r}\'izen\'i rozvodn\'e s\'it\v{e}, ale tak\'e statistick\'emu zhodnocen\'i
vlivu zv\'y\v{s}en\'e slune\v{c}n\'i aktivity. Ve spolupr\'aci s \v{C}EPS,
a.s., jsme statisticky vyhodnotili \v{c}etnost z\'avad na za\v{r}\'izen\'ich
p\'ate\v{r}n\'i rozvodn\'e s\'it\v{e} \v{C}R v z\'avislosti na \'urovni
slune\v{c}n\'i aktivity a ukazujeme, \v{z}e vliv n\'ahl\'ych eruptivn\'ich
ud\'alost\'i na z\'avadovost za\v{r}\'izen\'i \v{c}esk\'e rozvodn\'e s\'it\v{e}
nelze vylou\v{c}it.
