Electricity pylons are very sturdy. The Swiss extra-high-voltage grid is made up of steel lattice pylons that are spaced 300 to 500 metres apart. These pylons carry the conductors. The position of the pylons is chosen according to precise criteria. In exposed locations such as alpine landscapes, the pylons are subject to climatic and other variations such as changes in topography, shifting foundations and vibrations. These aspects can affect the inclination of the pylons, thereby altering their structural conditions and stability. Swissgrid launched the Pylonian innovation project in 2021 to constantly measure changes in these potentially dangerous environmental impacts. The name of the project is a reference to the English word «Pylon». Pylonian symbolises the «language of pylons», which Swissgrid is learning to understand with the help of telemetric data.

Round-the-clock monitoring

The first step of the project involved identifying exposed and potentially vulnerable electricity pylons in collaboration with internal experts. Internet of Things sensors were then placed on these pylons. The sensors are hardware components that recognise changes in their environment and collect the corresponding data. At the same time, Swissgrid’s Research & Digitalisation team developed and programmed data-driven algorithms to identify patterns and anomalies in the measured values. The next step was to create a monitoring tool in the form of a dashboard based on cloud infrastructure and internal tools. Since August 2022, this set-up has made it possible to monitor twenty electricity pylons around the clock in real time. 

The entire life cycle at a glance

The aim of Pylonian is to observe the condition of electricity pylons over their entire life cycle so that structural damage can be recognised as early as possible and any necessary maintenance work can be carried out in good time. For the test phase, an average of two to three sensors were installed at different heights on each pylon in order to register all the potentially harmful environmental influences that might affect the structure. The main factors measured are excessive vibrations and large inclinations, and to a lesser extent high temperature fluctuations or solar radiation. These four parameters are recorded around the clock, then monitored and analysed using the dashboard. If anomalies are measured, more precise analyses are carried out. In case of doubt, Swissgrid informs specialists from the Grids and Installations departments so that they can inspect the affected pylons on site. In principle, small variations in the measured values are normal and do not constitute an anomaly.

Durable, robust sensors

The IoT sensors used in Pylonian are extremely energy efficient and particularly robust. The battery is designed to last for at least five years, making it perfect for use in the field. The measured variables – vibration, inclination, temperature and solar radiation – are transferred using LoRa technology, i.e.  long-range low power, which enables energy-efficient transmission of data over long distances.

Improving predictability

Since the launch of Pylonian, no relevant deviations or anomalies have been measured that would have required the intervention of specialists on site. Although high vibration levels were occasionally detected, for example, these effects were associated with drilling work by a nearby company that produces cement. However, given that two-thirds of the grid infrastructure, including the electricity pylons, was built several decades ago, the longer it is in use, the more signs of wear and tear will occur that need to be kept under control. On the positive side, Pylonian can automate and continuously optimise the detection of emerging defects. This substantially improves the predictability of the infrastructure’s lifespan.

Gradual expansion possible

Based on the positive experience gained with Pylonian, Swissgrid is investigating the possibility of gradually expanding the project to hundreds or even thousands of pylons. This would bring considerable added value. Firstly, expansion of the project would make it possible to permanently observe the condition of pylons, and to apply and use monitoring tools and software for this purpose. Secondly, the measurements obtained would allow existing processes to be improved and damage to be prevented. In addition, Pylonian will enable expertise to be built up in relation to IoT projects which collect measurements via LoRa systems.