Hi Steven
As far as I know to mitigate the adverse transsient effect it is necessary to analize from several point of wiew depending of the electrical equipment, for instance; some equipments or machines are so sensitive that not adfmit voltage dip above 0.1 sec. meanwhile other acept up to 1.5 sec duration sag in power system. This isseu have to be analize indidualy accourding to each case in particalar.
The IEEE-1159 standard define voltage sag as decrease for about 10% to 90% during 0.5 to 30 cycles( 500 ms).
This disturbance can cause serious problem to any sensitive load with electronic componet also in motor coupled to process equipment due to speed reduction etc.
To mitigate the voltage transient (voltage sag) feeding different sensitive equipments you will choice as follow:
* UPS (mainly for control systems or light power load)
* DVR (Dinamic Voltage Restorer) [ for power & control]
* Induction double cage motor coupled to a flywheel –generator allowing the flywheel inertial absorb the voltage dip. I myself experienced that in a chemical process plant with successful results in control system avoiding nuisance
plant trip (1975)
That all I can say about it
Bye