Introduction: UK Power Networks have experienced disruptive link box failures over the last five years. Mitigations have been put in place to reduce the volume of these, and to limit the impact of this failure. However, there is more we could do to further reduce failures and we believe the root cause is high temperature and moisture ingress. In-situ monitoring of link boxes has not previously been conducted for a number of reasons, primarily because cost effective remote communications from link boxes has not been possible.  This cost barrier has been compounded by the harsh environments link boxes are installed in with a lack of auxiliary supply and extremely poor radio reception.  Due to this, link boxes require more frequent inspections than the majority of our assets which is expensive and resource-consuming. Having remote monitoring of link boxes will allow the time between inspections to be increased whilst concurrently improving the safety of the network.
 
Communication with link boxes were demonstrated in previous projects (SULVN and FUN-LV). In these trials, there were a number of data communication issues. These included missing measurement data and incorrect current direction. We believe advances in technology and our learnings from these other projects will enable us to develop a solution with higher reliability.

Objectives: The project objectives are two-fold:

1. Reliably communicate with devices installed under the bell cover of link boxes in a variety of environments.

2. Remotely monitor link boxes for abnormal running conditions and increases in temperature and moisture level.

3. Develop fault passage indicators which can be interrogated without lifting the bell cover of a link box.