Evaluation of Overvoltage Inverse Time Characteristic Use at Distribution System Protection and Its Impact on Voltage Sags and Interruptions Performance

摘要

The overcurrent protection philosophy has been generally employed as the only method to clear faults in power systems. However, digital relay and reclosers may have protection capability based on abnormal voltage changes, acting on overvoltages or undervoltages, not just overcurrent. Since single-phase-to-ground faults normally cause non-faulted phase overvoltages, a possible alternative for fault clearing would be to use protection based on voltage. Thus, a comparative study of a recloser protection operation at a distribution system is performed in this work. The recloser implements the overcurrent and overvoltage inverse time characteristics, given by 51 and 59 functions. It is analyzed the cases where both functions act, comparing the changes on the voltage sags and interruptions performance, as would be observed by industrial consumers. It can be noticed that the duration of more severe voltage sags decreased for some consumers when 59 function was used, although the number of interruptions increased for others.