Voltage sag solution

By S Kuwar-Kanaye, Impact Energy

 

Published in:

Electricity + Control, May 2015 (pages 32 – 33)

Enquiries: Email sishal@impactenergy.co.za

 

Download the full article on Voltage sag solution in PDF format.

 

Sags are short-term reductions in the RMS magnitude of the supply voltage lasting from a fraction of a second up to several seconds. Sags are described in terms of duration and retained voltage i.e. the percentage of the nominal supply voltage (RMS) remaining during the event.

Many dips are caused by faults on the supply network with the severity of the dip depending on the relative positions of the generator, fault and measurement point. According to IEEE 1159 voltage dip 0,5 to 30 cycles typical magnitude 0,1 -0,9 pu.

Voltage sags are becoming an increasing concern for process industries owing to an increase in the automation of systems. Automated facilities are more difficult to restart and the electronic controllers used are sometimes more sensitive to voltage sags than other loads. As a result, many voltage disturbances lead to disruption and financial deficits.

The enormous cost implications may seem trivial for events lasting less than a second. In particular for the continuous process industry, such as plastic extrusion or papermaking facilities, the effect of a dip is just as serious as a complete blackout that carries the same clean-up costs, raw material losses and loss of production.

 

Take note

  • Sags are short-term reductions in the rms magnitude of the supply voltage lasting from a fraction of a second up to several seconds.
  • Many dips are caused by faults on the supply network.
  • The Equalizer Turbo has been designed to provide a ride-through three phase voltage dip with a typical duration set for three seconds.