During periods of high solar activity, millions of tonnes of highly charged particles are ejected away from the sun during solar flares. As these particles approach earth, depending on the polarity of the particles, the earths magnetic field will either deflect them or draw them into the upper atmosphere down the lines of magnetic field.

As the particles stream through the atmosphere, then induce ground level charge of the opposite charge (much like lightning only of several orders of magnitude higher current). This induced ground current (under earth rotation) travels across the surface of countries, passing along the easiest (or most conductive) route. Unfortunately this often means overhead lines and cables. On the whole, the lines and cables are able to cope with this, but the transformers at the end of each circuit are at significant risk of over-fluxing and consequently the AC power component spills out of the core windings and flows around sections incapable of supporting it.

Overheating and damage to internal components can be disastrous, causing potentially catastrophic damage to windings. In these cases, it is not enough to simply detect the presence of the DC current, but it is absolutely necessary to have in place the ability to detect the early signatures of gas being produced from early failure modes.

Objectives

This project will deliver the ability for National Grid to not only quickly access whether significant DC current (induced from charged particles streaming into the atmosphere from solar events) are passing through power transformers, thereby allowing instant notification of potential over-flux and failure, but also for the first time, an integrated system of on-line dissolved gas analysis systems which will produce the evidence of any fault activity caused by the DC current within minutes of the event. All data captured will be high resolution (second by second) and be handled, viewed and automatically alarmed through the condition monitoring SAM platform.