Auto-Reclosing on Overhead Lines: A SelectiveApproach to Improving Grid Reliability
In today’s power systems, where grid reliability is becoming increasingly critical, the effective management of temporary faults on overhead lines is of great importance. In this context, auto-reclosing schemes stand out as one of the key solutions for reducing outage durations.
Approximately 80–95% of faults on overhead lines are temporary in nature. These faults are typically caused by external factors such as momentary contact between trees and conductors, lightning strikes, or various environmental conditions. In many cases, re-energizing the line after a brief interruption allows the fault to clear itself and enables electricity distribution to continue with minimal disruption. For this reason, overcurrent relays equipped with an auto-reclosing function play a critical role in overhead line applications.
Relays with an auto-reclosing function detect the fault, trip the circuit breaker, and automatically reclose it after a predefined time interval. In this way, outages caused by temporary faults can be cleared without requiring physical operator intervention. This approach is particularly valuable in substations located in rural or hard-to-access areas, especially where remote access via SCADA is not available, as it helps reduce both outage durations and operational costs.
Developed by ARF Technology, the FdPro 401 Overcurrent Protection Relay features a five-stage auto-reclosing function designed to adapt to different field conditions and operating scenarios. In the FdPro 401, each reclosing stage can be selectively configured according to different trip causes. This enables the relay to apply auto-reclosing selectively based on the cause of tripping and the nature of the fault, maintaining service continuity in appropriate scenarios while prioritizing grid safety in the event of permanent faults.
Thanks to its auto-reclosing function, the FdPro 401 helps prevent temporary faults from turning into sustained outages, contributes to the improvement of grid reliability indices such as SAIDI and SAIFI, and supports continuity of supply.
