Successful project behind Krafring's extended fault monitoring
The electricity grid that supplies us with electricity is monitored so that grid owners who The power ring can get information about when and where there are disruptions or interruptions. Monitoring can be done with the help of sensors. Of course, it is a matter of cost how many sensors can be installed and how large areas they will monitor.
It was in 2019 that Kraftringen began to consider what it would be like to monitor the power grid using an expanded number of sensors with wireless connectivity as part of the project Smart Public Environments (AS). At the start of the project Kraftringen monitored the network primarily in Lund's four distribution stations. The project had previously also installed a network suitable for transmission of sensor signals, a LoRa network, in Lund. Krafring felt that it could be practical and cost-effective if the existing network could also be used for wireless communication of signals from an increased number of sensors for fault monitoring.
When the network was only monitored in the four distribution stations, it took relatively long to pinpoint where the fault occurred and large areas had to be shut down while troubleshooting was ongoing. Sometimes it was customers who were not really affected who were left without electricity. The project had the ambition to find opportunities to monitor smaller parts of the network. The distribution stations pass the power on to loops of grid stations. In the project, sensors were installed in two of these loops.
- With sensors and measurement in one or more network stations in the loop, we can directly obtain information about where in the loop the error has occurred. This makes it easier for us to locate the fault and turn off the right part, which means that customers who are not directly affected only get a short interruption,” says Håkan Skarrie, business developer at Kraftringen.
The experiment with the two sensors in the loops with network stations went well and now Kraftringen has deployed a total of twelve sensors in a similar way. In the fall of 2022, it is planned for another 20. There are approximately 500 network stations in Lund, and Kraftringen expects to deploy a total of 100 sensors over a two-year period in Lund and the surrounding area. It should provide good monitoring, both in Lund and in Kraftringen's other owner municipalities Lomma, Eslöv and Hörby.
- The idea is not to have sensors in all stations, but we choose strategically to get as much benefit as possible on as few sensors as possible, continues Håkan Skarrie. For example, if you have monitoring in the middle of the loop, you can immediately cut the problem in half.
The cables in Lund are often buried and it is very rare that there is a power outage.
- Therefore, it is especially important that the equipment works when it is needed. But there has also been an evolution in how we use the sensors. From the beginning they only showed when it was wrong, now they also make a current measurement. The current values show how loaded a transformer is, which is good to know so that we can make an action if they are on the verge of what they are capable of. In addition, this measurement gives us a check that the sensor is working.
Much of what is being done now is similar to the attempt made in the SOM project. As in the project, Kraftringen uses Sensativas IoT platform Yggio. In the project linked Protrol up the sensors via the LoRa modem developed within the project. After the end of the project, they have developed their own modem which is now in use. Kraftringen has produced a visualization of fault monitoring via lund company Qliks system. As for the connection, some small adjustments await.
- We will be able to look and analyze how the communication via the LoRa network itself works. Kraftringen has a LoRa network in Lund, but at the moment there is not good coverage in all of Lund, but it is gradually being expanded as needed. We need to know how good coverage is required for us to get the signal in. We need to learn what types of antennas are needed each and then build out according to our needs. We can connect with other communication technologies, it is not certain that LoRa technology is the best everywhere, for example in rural areas.
What would you say the biggest benefit of the project was?
- We had set up surveillance even without the SOM project, but most likely it would have been a different communication technology. The value of the project was that we can now do it via LoRa, and since the network already existed in Lund, it became an easy and inexpensive way to communicate data,” concludes Håkan Skarrie.
In the SOM project, Sensative, Kafringen, DLaboratory, Intive, Protrol, T-maps, Mobile Heights and DivM participated in the development of the fault monitoring.
The subproject within SOM lasted between 2019-06-30 and 2020-12-18. Financier was IoT Sweden.
Picture: Håkan Skarrie at Kraftringen in front of a network station.