Overvoltage Control Research Articles

Control of Overvoltages on Energizing Capacitor Banks

Transient voltage phenomena occurring during the energization of shunt capacitor banks, due to prestrike and temporary interruption in the switching device of inrush currents have been considered. An analysis is made of a generalized capacitance circuit and energization transient voltage pattems are shown for a range of circuit permutations. An application guide is discussed for reduction of overvoltages during capacitor bank energization by proper choice of circuit elements. The influence of circuit resistance on the bus voltage patterns is reviewed.

Overvoltages Due to Line Energization and Reenergization Versus Overvoltages Caused by Faults and Fault Clearing in EHV Systems

One of the main problems in EHV and UHV systems is the control of transient overvoltages of internal origin. The first part of this paper investigates different approaches to limit over- voltages due to line energization and reenergization; the second part deals with fault and fault-clearing overvoltages. Finally, the relative severity of the former type of overvoltage versus the latter in EHV and UHV systems is compared.

A Laboratory Investigation of Ferroresonance in Cable-Connected Transformers

Results of a full scale laboratory investigation into the ferroresonance phenomenon are presented. The investigation consisted of energizing and de-energizing three-phase 13-kV padmounted distribution transformers with single-phase cutouts. Applied cable lengths ranged from 100 to 5000 feet. In addition to three- phase switching, the application of resistive loading from 1 to 4 percent was also investigated as a preventive measure. Results indicate that three-phase switching, the use of a wye-wye transformer with both neutrals grounded, and the presence of secondary load are all effective in the control of ferroresonant overvoltages.

Overvoltage detection in single and multigenerator aircraft A-C systems

OVERVOLTAGES resulting from fault conditions in aircraft a-c electric systems being designed at present can cause extensive utilization equipment damage. Until such time as aircraft power generating and regulating equipment design results in reduced overvoltage possibilities, it is likely that an overvoltage control relay will be installed in many single-generator systems.