There are more reasons than ever for greater transparency through better monitoring of distribution networks – but the needs of network operators vary greatly. We have adapted our range of solutions to meet these different requirements.
According to the "Report on the Status and Expansion of Distribution Networks 2022", more than 860 companies in Germany operate a medium- and/or low-voltage network, and they are all currently facing the challenge of making the utilisation and condition of their operating resources more transparent. It is obvious that the individual companies differ considerably in terms of their existing facilities, the development of feed-in and loads in the network area and, last but not least, their budgetary possibilities. Solution providers must adapt to this situation – and they are doing so.
As a specialist provider of IoT solutions "from sensor to cloud", comtac AG has frequently dealt with tasks related to condition monitoring in industry and in the municipal utility sector. "The path to solutions for digital condition monitoring of distribution networks was therefore not far off – especially given our many years of experience in telecontrol technology," says Uwe Scholz, who is responsible for business development at the Swiss company: “We recognised early on that there was a considerable need for solutions for monitoring and controlling infrastructure facilities such as transformer stations, distribution boxes, mast switches and other network components.”
According to the "Report on the Status and Expansion of Distribution Networks 2022," more than 860 companies in Germany operate a medium- and/or low-voltage network, and they are all currently facing the challenge of making the utilisation and condition of their operating resources more transparent. It is obvious that the individual companies differ considerably in terms of their existing facilities, the development of feed-in and loads in the grid area, and, last but not least, their budgetary possibilities. Solution providers must adapt to this situation – and they are doing so.
As a specialist provider of IoT solutions "from sensor to cloud", comtac AG has frequently dealt with tasks related to condition monitoring in industry and in the municipal utility sector. "The path to solutions for digital condition monitoring of distribution networks was therefore not far off – especially given our many years of experience in telecontrol technology," says Uwe Scholz, who is responsible for business development at the Swiss company: “We recognised early on that there was a considerable need for solutions for monitoring and controlling infrastructure facilities such as transformer stations, distribution boxes, mast switches and other network components.”
Complete solution as a starting point
Transformer stations are ubiquitous in distribution networks, and the requirements for a monitoring solution are as diverse as these network elements themselves. Stadtwerke München (SWM) was one of the first network operators in Germany to launch a project to digitise and optimise the operation of its existing distribution network. The choice fell on a complete solution, which comtac AG implemented together with its partners EPS Energy and ACAL BFI and in close coordination with SMW. It is now available as the "Trafo Stationsmonitor (TSM)". These devices can record signals for rapid fault localisation as well as data for assessing the status of the network, faults and equipment, and transmit this information to the network control centre using LoRaWAN® long-range radio technology. As an alternative to LoRaWAN®, the TSMs also have an Ethernet connection.
What transformer monitors can do
The TSMs fulfil three tasks: The first and most important is to report acute faults and supply failures – primarily short circuits and earth faults – for rapid fault rectification. They have digital inputs for this function. The second task is to monitor potentially critical operating conditions such as compliance with voltage and current limits and transformer temperature.
The third task is the permanent monitoring of power quality on the low-voltage side: "To this end, comtac AG also offers 'intelligent' voltage and Rogowski current sensors that can be connected via Modbus. With the help of these components, the TSM provides not only current and voltage values but also quality parameters such as cosϕ active/reactive power and load flow direction," adds Uwe Scholz. These sensors are connected using the daisy chain principle ("clothesline"), which means that the cabling effort during commissioning is low and can be done with normal Ethernet patch cables. The Rogowski current sensors are characterised by high measurement accuracy, easy handling and an auto-ranging from 63 A to 2 kA. The sensor automatically determines its measuring range based on the measured value, thus increasing measurement accuracy without further settings or parameterisation. Modbus also allows the connection of additional external devices, such as short-circuit indicators.
In view of the high building penetration and comparatively low costs, SWM independently chose data communication via LoRaWAN. However, interesting alternatives – such as the 450 MHz network designed for operators of critical infrastructures – were not yet available at the time of the decision.
Solutions for different requirements
In sales practice, however, comtac AG found that even the "complete solution" does not meet all requirements: "Not every network operator needs the full range of TSM services. Instead, many are looking for a more compact solution that is also suitable for cross-current analysis in cable distributors," says Uwe Scholz. In addition, new technologies and even "ready-made" radio networks for monitoring applications in distribution networks are now available. "That's why we have developed a compact telecontrol device as an alternative to the TSM: the configurable controller and monitor Cluey." Originally designed purely as a short-circuit monitor for earth faults and short circuits, Cluey in its current form is designed for numerous applications in which digital signals, counting pulses, analogue values or temperatures and/or control commands are to be output – including and especially in transformer stations. The Cluey can operate with both a 24 V supply and low-power battery operation and is also available as standard for other radio technologies such as 450 MHz, CAT M1, LTE or mioty.
Cost-effective retrofitting
The integrated battery-backed power supply and easy connection to private or public networks allow cost-effective upgrading of transformer stations for faster fault localisation and restoration of power," explains Uwe Scholz. The Cluey MB enables flexible connection of various end devices via a Modbus interface. As standard, the device is therefore suitable for a range of applications in combination with Modbus devices and an I/O level. For monitoring transformer stations and cable distributors, the Cluey MB comes with additional application software that covers alarm and event handling, data preparation and compression, and other functions. The Cluey MB is particularly suitable for retrofitting existing systems, where installation space is usually very limited. Despite its small dimensions, it provides all the important measurement variables from the distribution network in conjunction with the modular voltage and Rogowski current sensor concept. The Cluey MB thus combines a wide range of applications with cost-effective installation and commissioning as well as a high degree of flexibility. Uwe Scholz: “If the customer has additional requirements, we can implement them on a project-specific basis. In addition, the system can be easily connected to all visualisation and control technology systems, so that the user does not have to commit to specific service providers or products.”
Operators have (no) choice
Monitoring distribution networks is a key element of a future-proof smart grid. Because heterogeneous networks require different monitoring approaches, comtac AG believes that offering network operators a choice between two solutions has nothing but advantages. Uwe Scholz: “Operators hardly have a choice anymore if they want to monitor their distribution networks more effectively and thus make them more transparent and resilient. This makes it all the more important that they have the choice of how and with which radio network they want to create more transparency and resilience.”
Read the full report in the trade magazine "50komma2": One goal, different paths (PDF in German)
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