| Summary: | The power quality performance of South African utilities has been regulated through the
application of NRS 048-2 standard. The earliest edition of the power quality standard (NRS 048-
2:1996) defines compatibility levels for voltage dips in the form of annual dip limits for each
voltage dip type. Actual measured utility dip performance has consistently resulted in higher dip
numbers than the limits imposed in the standard. On the other hand, the dip limits were
considered to be less restrictive by industrial customers. The revised power quality standard
addresses the difficulties in managing voltage dip performance based on dip limits as specified in
the first edition of NRS 048-2. This new philosophy does not define dip limits; instead, utilities are
required to develop specific strategies to manage dip performance according to customer
requirements. This research work develops an alternative approach to the management of dip
performance as opposed to the application of dip limits. The study analyses measured voltage dip
records for a steel-processing plant and a pulp and paper plant. The supply network for each plant
is modelled to define dip influence zones as a function of fault locations. The principal results of
this study are critical circuits, causes of dips, dip influence zones and the key elements of the
proposed approach in communicating dip performance. The optimised approach was presented to
and adopted by the customers involved. === Thesis (M.Sc.)-University of KwaZulu-Natal, Durban, 2009.
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