Problem:
The HV supply feeding three water pumping station which are absolutely essential for the operation of the mine, were suffering severe damage due to lightning discharging onto the HV lines or poles. The massive over - voltage destroyed the HV insulators causing line failure. This means that the mine would go off line for at least 24 hours for the repairs to be undertaken only to have the same problem occur during the next storm. An initial solution of an earth catenary wire was installed a number of years earlier with the intention of intercepting the lightning strike. Unfortunately this catenary wire solution was unsuccessful.
Solution:
LDU was approached by the mine to investigate and propose a solution to the problem. The major problem was that the HV lines extended in 3 directions for kilometers, and we could not install a system on each and every pole. Therefore our consulting company, LDU Consultants Pty Ltd, conducted a statistical analysis of all the damage to the feeds for the past 10 years to discover a number of hot spots which indicated the common paths for lightning storms. Next we developed a plan and designed a trial which saw us install 14 systems consisting of a Prevectron S6.60 terminal and a HV Surge protection for each phase, on the 14 poles. The terminals were selected to protect not only the pole, but the cables in between the two poles where possible.
Outcome:
Since the installation completion in 2008, LDU has not received any reports of damage to the areas we protected. This means that the excessive downtime experienced by the mine were reduced considerably if not totally, saving millions of dollars of lost productivity.
