Grid operator Western Power Distribution has demonstrated detection of multiple automatic reconnection events, paving the way for incentivized reductions.
The initiative undertaken as part of the Power Pointer project for OHL (Overhead Line) has provided a sensor-based solution offering centralized recording of circuit breaker and short circuit breaker operations.
This is likely to be particularly useful for older switchgear that is not connected to a SCADA network and a switch to increase network visibility.
Rural overhead feeders are prone to intermittent failures, such as those caused by tree branches or blown insulators, with consequent outages to customers.
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It is estimated that up to 80% of outages in the UK’s distribution networks are short, lasting less than three minutes.
Due to the rural nature of its customer base, Western Power Distribution was experiencing a significant number of temporary outages along its feeder and branch lines. In turn, they often created constant outages, requiring the dispatch of a repair crew and increased O&M costs.
Reduction of short-term interruptions
The aim of the project, which started in 2019 and ran until May 2022, was to reduce the number of such outages with circuit breakers with automatic reclosing sequences, with their potential to detect transient events of short duration and help prevent them from becoming constant interruptions.
The solution, implemented in an overhead line grab sensor – called an “intelligent navigator” – has been deployed at several locations across Western Power Distribution’s networks and includes a counter system to record circuit breaker tripping operations on a phase-by-phase basis. Transient (and permanent) faults are captured in a series of additional counters, where a fault event (overcurrent or ground fault) causes the counter to change incrementally for each compromised phase.
In addition to the individual counters that record activity for each phase, there is a logic sequencer that reviews the events and increments the counters on a set basis (all three phases, i.e. per circuit), thereby accounting for short breaks and permanent breaks of an accident’.
Findings from field trials show that automatic recloser detection has been successful in multiple trial locations, the company said in its final report. Some technical irregularities were found in the error recording algorithms in the transient and persistent error counters, which will be updated in an over-the-air firmware upgrade.
The OHL Power Pointer project was funded by Ofgem through its Network Innovation Facility to trial a device that can operate autonomously and provide real-time information on voltage, current, directional power flow, conductor temperature and fault activity.
Western Power Distribution concluded that the technology readiness level (TRL) of the automatic recloser detection solution increased from TRL5 to TRL7 over the course of the project. It can also be used to help provide a regulatory mechanism to incentivize the reduction of short outages – the lack of reliable data across all network operators has hindered roll-out so far.
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Western Power Distribution trials smart auto-reclosers on GB networks
