Medvedeva M. L. – Expert center LLC, Ekaterinburg, the Russian Federation. E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
Kuz'min S. V., Kuz'min I. S., Shmanev V. D. – Research and Production Enterprise “Rutas” LLC, Ekaterinburg,
the Russian Federation. E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
ISSN 0536-1028 «Известия вузов. Горный журнал», № 5, 2017 73
At the present stage of mining enterprises power supply development, the main reasons for emergency shutdowns are
connected with the emergence of single-phase ground faults (SPGF). SPGF occurs 3.88 times more often than the short
circuits (SC). In the article the causes of SPGF and SC in the networks of 6–10 kV of the mining enterprises are analyzed.
To the main reasons for emergence of SPGF and SC refer: the switching overstrain (SO), overstrain in SPGF mode, and
natural aging of isolation. It has been shown that from 2005 to 2015 switching overstrains transformed from minor factors
into the main reasons for SPGF and SC. It is connected with the growth of a share of vacuum switches in the total of the
switches used at mining enterprises and low efficiency of nonlinear surge arresters by means of which SO is limited.
The share of vacuum switches at mining enterprises changes from 57% to 67% from the total quantity of switches
depending on the type of the mining enterprise. Wide use of vacuum switches has led to the growth of SPGF and SC 1.9
and 1.8 times respectively. The article indicates the need of effective restriction of SO, whereas in order to reduce the
number of group shutdowns it is necessary to limit overstrain effectively in SPGF mode. Besides it has been indicated
that the natural aging of isolation connected with technology and climatic factors influences SPGF in the networks
of 6–10 kV in pits and coal mines.
Key words: single-phase ground faults; short circuits; switching overstrain; natural aging of isolation; overstrains of arc
single-phase ground faults.
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