1. Detrich CZ Session 2 – Block 4 Barcelona 12-15 May 2003 1 SOME NEW RESULTS OF RELIABILITY ANALYSES CARRIED OUT IN MV DISTRIBUTION NETWORKS Vaclav DETRICH, Karel MATONOHA, Zdenek SPACEK EGU Brno a.s. - Czech Republic Milos GÖHLER PRE a.s. – Czech Republic

2. Detrich CZ Session 2 – Block 4 Barcelona 12-15 May 2003 2 Approaches Applied Principle of non  homogeneity - components of the same type do not reveal similar behaviour as to failure rate, Principle of non-linearity – in some cases there is no linear dependence between the length of a feeder and its failure rate, Principle of respecting the factor of time - there can be a variation in failure rate in the course of time, when considering a ten-year period of observation.

3. Detrich CZ Session 2 – Block 4 Barcelona 12-15 May 2003 3

4. Detrich CZ Session 2 – Block 4 Barcelona 12-15 May 2003 4 Dependence of the probability of occurrence of failures on a string of supply and distribution feeders occurring more frequently than k-times during the period of observation

5. Detrich CZ Session 2 – Block 4 Barcelona 12-15 May 2003 5 Envelopes of trend characteristics of the development of the duration of supply restoration up to fixed time limits on 22 kV supply cables