Myth Busters for LV Networks

MYTH: Nothing ever happens on LV networks.

Recent developments have proven that this is not true. Thanks to advanced monitoring equipment deployed as part of the Foresight project, over 35,000 events relating to pre-fault activity and quality of supply issues have been recorded. This newfound visibility of the network has given Northern Powergrid the chance to address issues before they become critical and get ahead of potential faults. Moreover, they’ve been able to shed light on the quality of supply issues, which range from flicker to illegal extraction. 

MYTH: Most LV cable faults are single phase.

Not true. Faults that cause off supplies due to protection operations are mostly multiphase. Pre-fault events are however mostly single phase.

MYTH: Replacing just the fuse that is blown should be good enough for transient faults.

Most faults are multiphase, but reporting them as single phase is an easy mistake to make when only one fuse blows. In reality, the fuses on each phase are essentially in a race to interrupt the current first. And while one fuse will successfully do so, the others are unable to fully recover before being called to action again. This can lead to a dangerous and exhausting cycle as the weakest fuse is continually replaced each time the fault occurs. Ultimately, it’s important to address multiphase faults properly to avoid potential damage or harm.

MYTH: Phase-to-phase faults do not generate any significant neutral current.

Not true – most of them do. The VisNet Guard utilises this current to localise the source of the fault to a particular feeder.

MYTH: You cannot find faults until they go permanent, which usually means customers are off supply. 

Not true – actually, you can. This is what the Foresight project has proven. Not only can you find them, but you can fix them too. “Find and Fix before fault” is becoming a practical reality