Sinclair Knight Merz was commissioned by Western Collieries to design the power supply to Premier Mine with the following design criteria:
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ultimate electrical excavator fleet for substation design purposes of two P&H electric shovels
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a maximum demand of 7500 kW in five years
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mine distribution voltage of 22 kV.
The following considerations in the design of the power supply included:
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availablity of the power supply versus the consequence of power outage
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a high fault level was required to limit voltage fluctuation caused by excavator swinging loads
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the equipment had to be rated for the electrical impact loading caused by excavators, where the momentary load on equipment can substantially exceed equipment nameplate rating
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harmonic distortion due to static motion drives on excavators.
The main features of the proposed supply to the mine were:
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a 132 kV substation established adjacent to the mine infrastructure. The substation was separated into two sections; one operated and maintained by Western Power and the other by WCL
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the Muja-Worsley 132 kV transmission line routed into and out of the Western Power switchyard
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two 132/22 kV 10/13 MVA transformers, each capable of supplying the total mine load
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a 22kV indoor switchboard to distribute power to the mine. The existing WCL load was also to be transferred to this system.