Open Cut » Maintenance & Equipment
ACARP project C21030 looked at the applicability of using power electronics for voltage stabilisation in open cut and underground coal mining. The primary outcome has been the analysis of voltage stability issues and the systematic validation of the capability of a Static Compensator (STATCOM) to mitigate these issues. The cost/benefits of the mitigation strategy are rather difficult to evaluate due to lack of data associated with operational loss.
Electrically, the STATCOM has been shown to improve voltage stability through the dynamic injection of reactive power to reduce voltage sag under severe load conditions. Key performance characteristics have been derived from captured mine electrical data and applied to the STATCOM control algorithm. Simulation mine models were validated as accurate using the captured mine data, then results were collected with modelled STATCOM compensation added to the network. These results showed the applicability of STATCOM technology to provide voltage stability in a mining environment. Transient voltage dip due to DOL induction motor start was reduced by more than 50% to remain within .95pu under severe transient load increases, and general voltage stability during simulated operation was kept to within 99% of nominal voltage at all times.
Whilst definite electrical benefits can be seen, the cost/benefit of implementing a STATCOM solution to voltage stability may prove marginal, except in extreme cases. Technology benefits are not limited to voltage stabilisation however, more gains may be found in harmonic compensation as VFD technology uptake increases in Australian mining. Smaller and lower cost active harmonic filters may be more cost effective in this area if other technologies such as mine automation and electronic monitoring are going to be adopted. The bigger issue for surface mining seems to be harmonic compensation. Machine electrical interaction is already an industry issue and can be ideally mitigated using power electronic technologies.