Project Overview
In response to suspected malfunctioning of some Automatic Sectionaliser Links (ASLs), together with wider industry supply chain challenges, PNDC partnered with SP Energy Networks to test alternative devices from multiple manufacturers at its Wardpark site, using both the controlled LV laboratory environment and the live HV distribution network to apply fault conditions that cannot be imposed on a customer-serving network.
the extension spindle can be seen at the bottom left.
Testing Programme
The project focused on performance under low load currents typical of rural networks, highlighting limitations in wake-up thresholds, fault discrimination, and inrush handling, while assessing the potential of configurable solutions such as the NOJA Ecolink, Inael SPIN, ABB WiAutoLink, and Hubbell Three-Phase Programmable Resettable Sectionalizer (PRS).
Testing was carried out in two phases. Initial characterisation in PNDC’s Low Voltage (LV) laboratory assessed key operational parameters under controlled conditions, followed by High Voltage (HV) network testing to evaluate earth fault protection and the ability to distinguish between fault currents and magnetic inrush detection.
Findings
Manufacturer datasheets and vendor claims provided a useful starting point, but several operational behaviours only emerged once the devices were exercised under realistic fault and network conditions. Some performed in line with published specifications; others showed unexpected behaviour around ganged operation, wake-up functionality, communication reliability and magnetic inrush discrimination — none of which would likely have been identified from datasheet review alone.
Testing devices from four manufacturers to the same programme, on the same network, also allowed direct comparison across the parameters that matter operationally: wake-up current and time, pickup current, reclaim time, inrush discrimination and earth fault response.
Close engagement with manufacturers’ technical teams was central to the work. Direct collaboration supported troubleshooting, device configuration and firmware adjustment as issues arose, and gave manufacturers evidence of operational limitations that factory testing had not exposed — in several cases feeding into planned product development.
Video of LV lab testing with the Inael, ABB and Hubbell ASLs
SMARTer selection of Automatic Sectionaliser links.
Some of the behaviours we saw only appeared once the devices were on a live network under real fault conditions — they weren’t in any datasheet, and they hadn’t shown up in factory testing. Working through those findings with SP Energy Networks and each manufacturer meant the issues could be understood and addressed, which is ultimately what gives a network operator confidence in what they’re deploying.
