On the Development of Overcurrent Relay Optimization Problem for Active Distribution Networks

Abstract

The goal of this review paper will be to address complex optimization functions in the area of overcurrent relay optimization, to inspect and valorize their objectives and to critically examine their application in real distribution networks. Special emphasis will be put on observing the optimization of discrimination time between primary and backup relay pairs, and methods which prevent the latter becoming penalty functions will be shown. Furthermore, the impact of distributed generation units on the overcurrent relay optimization problem will be elaborated in detail. Protection settings of all the existing and new relays must be thoroughly inspected before the connection of new production units, because contributing fault currents may have a significant effect on the solution of the overcurrent optimization problem. This is because the relays being used are of an inverse-type. Next, meshed network operation will be critically assessed in comparison with the actual practice of radial operation, and some topologies will be highlighted for future research, while others will be discarded. The distribution network in mesh operation implicitly suggests using numerical relays on both sides of protected elements (usually lines), so their total number will be much higher than in radial operation. Finally, a relatively new concept of adaptive distribution network protection will be reviewed, and its potential application to the overcurrent relay optimization problem will be examined. The purpose of this review paper will be to lay a groundwork for future research papers by inspecting the overall development of the overcurrent relay optimization problem for contemporary and future active distribution networks.

Optimal Protection Coordination of Active Distribution Networks Using Smart Selection of Short Circuit Voltage-Based Relay Characteristics

“…The normal current passing through the relay is indicated by I load , and the minimum allowed current setting of DOCRs has been shown by I b.min in (2). The time and current settings of DOCRs should be determined by the designer of the protection system [42,43]. In the proposed hybrid protective scheme, both time and current settings (TMS and I b ) are optimized.…”

A Comprehensive Review of Fault Diagnosis and Prognosis Techniques in High Voltage and Medium Voltage Electrical Power Lines

“…Their extremely branched and complex configuration requires the exclusion of the faulty branch and its safety before the utilities can be powered by alternative routes. Furthermore, the presence of generators from renewable sources that feed into the distribution network introduces a further factor of complexity for the management of the line in fault conditions [48]. Basically, in MV networks, the main protection activities are carried out by means of overcurrent relays in conjunction with auto-reclosers, fuses and/or section switches [49].…”