The operational availability of mining shovels is the focus of this work. The hypothesis is that energy quality is responsible for the frequent shut downs of the shovels. Previous engineering studies have highlighted a large presence of harmonics and reactive power in the mine loop electric system. A common solution proposed was to use a combination of active filters, larger mobile substations, shorter mining cables and equipment location constraints. The aim of this paper is to produce a precise diagnosis of the source and nature of the energy quality issues. Mine loop electric quality monitoring, system modeling, equipment technologies and shovel´s histograms are considered. Results are measured against IEEE standards and shovel´s voltage regulation susceptibility. With the diagnosis the goal was to produce a reliable cost effective solution. Different alternatives are crosschecked with this paper proposal. The solution presented provides energy quality well within shovel´s susceptibility and improves energy efficiency. The lower energy consumption pays the investment required and is currently under construction.
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Mining Cable (7.2[kV]) Power Line (13.8[kV])0093-9994 (c)
This paper presents an energy quality evaluation of an open pit mine distribution system. A number of operational disruptions affecting mine shovels have been related to energy quality. Previous investigations have highlighted the large presence of harmonics as the main factor responsible for these problems. The aim of this paper is to produce an energy quality baseline and a precise diagnosis of the source and nature of the energy quality issues based on standards and the susceptibility of different technologies used by the shovels at the site. The random nature of the load composed by multiple shovels and drills requires computer simulation to predict worst-case scenarios. For this purpose a voltage regulation and harmonic distortion study was conducted with the model parameters tuned by measurements taken in mobile substations of the mine energy loop. A major aim of this study is to establish the relationship between energy quality and energy efficiency.
The proposed system is suitable for current-mode segmented intercell bars. Previous developments show that these bars provide protection against short circuits but are sensitive to open circuits and dirt contacts. This new system adds segmented sidebars to interconnect in groups the otherwise electrically insulated cathode and anode hanger ends. The combination of a segmented main bar with these sidebars offers protection against short circuits, open circuits, and impaired contacts.
The proposed system is suitable for current mode segmented intercell bars. These bars are immune to short circuits but sensitive to open circuits and dirt contacts. This new system adds segmented sidebars to interconnect in groups the otherwise electrically insulated cathode and anode hanger ends. The combination of a segmented main bar with these sidebars offers immunity to short circuits, open circuits and bypasses dirt contacts. Moreover, exhibits the best current balance ever reported ensuring high energy efficiency.
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