Westnetz GmbH relies on Smart Navigator 2.0
Toppled trees, lightning and other natural causes often lead to disruptions to power supply via overhead lines. Troubleshooting is usually time-consuming for network operators. In addition, disruptions have an impact on revenue ceilings in the context of quality regulation. That’s why Westnetz GmbH is pushing ahead with the digitalisation of its medium voltage grid. Following a pilot phase, 400 sets of Smart Navigator 2.0 (SN 2.0) intelligent overhead line short-circuit indicators from Horstmann will be installed in the medium voltage grid to monitor this.
As the largest distribution network operator in western Germany, Westnetz is responsible for numerous overhead lines in addition to the relatively fault-resistant underground cables. Many of them are located in rural areas with complex topography. This presents the network operator with some challenges because the overhead lines are not only more prone to faults, but also often cause time-consuming and cost-intensive troubleshooting measures. So far, the source of a fault in the overhead line network can often only be located locally – by reading short-circuit indicators in the overhead line sections – and not remotely. Therefore, service crews go out and narrow down the faulty line section kilometre by kilometre until the cause of the fault is found. They often have to work their way through forests and rough terrain, which further complicates the search. Since the duration of the fault and the service disruption in such cases are a significant factor for quality regulation, time and cost pressure is correspondingly high.
Intelligent fault detection: Smart Navigator 2.0
Westnetz was looking for a simple, safe and efficient solution to be able to locate faults and disconnect overhead lines much faster in the future. The network operator came across the Smart Navigator 2.0 intelligent overhead line short-circuit indicator from Horstmann. The robust and compact measuring device is mounted at strategic locations in the overhead line network, and continuously and reliably monitors them. It measures the current, load flow direction and conductor temperature. Faults and other information are transmitted to the control centre and help to quickly and clearly identify problems. In addition, faults are displayed on-site via an ultra-bright LED on the SN 2.0. To test the performance of the Smart Navigator in practice, Westnetz conducted a test phase lasting several months in three regional networks with increased local fault occurrence probability in the South Eifel, Sauerland and Siegerland regions.
The devices survived Storm Sabine
One test region was located in the Eifel. In the medium voltage grid monitored from Trier, four SN 2.0 sets were installed at particularly fault-prone locations. During the entire pilot period, they reported all relevant faults reliably and correctly, without a single false alarm. “This was very important for us, because lightning strikes, for example, can lead to fault messages that can then no longer be traced on-site,” explains André Felten, Operations Manager for Low Voltage and Medium Voltage Networks in the Trier Regional Control Centre. Storm Sabine was a special test for SN 2.0 devices – it caused power outages throughout Europe at the beginning of February 2020. Despite the extreme weather conditions, the four installed short-circuit indicator sets reported seven real faults during the hurricane, without a single false alarm, and thus relieved service crews and control centre staff of a considerable amount of pressure.
Next step: roll-out with 400 sets
After the successful pilot phase, Westnetz is now starting the large-scale installation of SN 2.0 devices. A total of 400 short-circuit indicator sets will be distributed over a network length of more than 8,500 km at strategically selected and fault-prone locations. André Felten expects much faster and more economical troubleshooting than before: “Our service crews no longer have to patrol the entire line pole by pole and know in which direction they have to look for the fault.” In view of the complex troubleshooting and the Federal Network Agency’s penalty scheme, a Smart Navigator 2.0 can pay off from the first fault in the monitored line – depending on the type and duration of the fault.
Easy handling, long service life
The installation and commissioning of SN 2.0 is particularly straightforward. Employing ‘live-line working’ procedures, the devices are simply hooked onto the overhead line using an insulating rod. They are powered using energy harvesting from the overhead line load current. The dynamic adaptation to load conditions means that a conductor current of 5 A is sufficient for the supply. Software updates and configuration adjustments are possible through an LTE connection via remote maintenance from the control centre. The long service life further increases the cost-effectiveness of the monitoring systems, a service life of 20 years can be expected with one battery change.
iHost server and software
The SN 2.0’s fault messages and measured values are transmitted via the integrated modem to the iHost software developed by Horstmann. In the test phase, Westnetz used Horstmann’s iHost Cloud server platform. “Our customers can log into this server platform to retrieve their monitoring data. This is especially true for pilot projects and is a quick and easy solution for smaller applications,” explains Vincent Vogt, Westnetz Project Manager at Horstmann. However, a different solution is required for the subsequent operation of the 400 SN 2.0 sets. That is why Westnetz has installed the iHost software on its own specially protected server from which data is fed into the control system. This is important because Westnetz, as an operator of critical infrastructure, has the highest requirements for IT security and data protection and is required to meet them.
Network digitalisation perspective
The introduction of the SN 2.0 short-circuit indicators is a further step in the direction of grid digitalisation for Westnetz. The intelligent devices not only detect faults, but will also provide more transparency in the overhead line network in the future. “The data provided by SN 2.0 opens up many new possibilities for us. Their subsequent evaluation will allow us to better understand what is happening in the network and what conclusions we need to draw for further network expansion, for example,” explains Anna Carina Schneider, Deputy Head of the Technology Department at Westnetz, who is leading the project together with André Felten.