Large metropolises are not the only place where infrastructure is struggling to keep up with the growing population. Even in smaller cities, the existing road, electricity and water networks have often not been adapted to the changing requirements. Now, however, a rethink is taking place. Radar-based level sensors provide the measured values necessary for this transformation.

Infrastructure systems are among the least digitally transformed sectors of the entire global economy. Even new infrastructure facilities have been planned, built, operated and maintained in the same old way for decades – even though intelligent solutions have been available for a long time.

In the Middle East, cities are now looking for intelligent solutions to challenges in urban development. True to the motto that you can only improve something if you have reliable information about the actual state of affairs, numerous parameters are now being acquired to monitor different operating conditions and make them suitable for use in digital applications. Typical measurements involve, for example, the monitoring of traffic flows, lighting conditions, fire detection systems, logistics, internet data consumption as well as drinking water and wastewater flows. In these areas, radar level measurement technology makes it particularly easy to obtain reliable data.

OUTDATED TECHNOLOGY IN USE

The current situation: Ultrasonic sensors are still used in many applications, be it in sewers, open channels or pump shafts. Until a few years ago, this was the preferred – and also inexpensive – measuring method. However, this method was only reliable if the ambient conditions were perfect. Changing temperatures, condensation, deposits or buildup led repeatedly to measurement uncertainties. In the event of flooding – a not uncommon occurrence in closed sewer networks – the instruments often transmitted incorrect values at key moments.

There are similar problems with pressure gauges, which are also used for measuring water levels. Both pneumatic and hydrostatic measurements reach their limits, for example, when sludge or fat deposits clog the membrane of the pressure sensor, preventing correct measurement.

Smart sensors using the LoRa network or the NB-IoT/LTE-ME network to send data to a server

Meanwhile, a much more reliable measuring method exists that is not bothered by the above-mentioned adversities. It is a non-contact measuring technique based on a different physical principle. Radar measurement technology lays the foundation for the digitisation of water and wastewater management.

UNDERGROUND DRAINAGE SYSTEMS

Level sensors measure the flow in underground water networks. They report when sewer pipes are clogged or when shafts are flooded during heavy rains. In such cases, the pumps in pumping stations have to remove the water. Early information in the form of sensor data helps cities to prepare for such events.

Monitoring the levels in natural bodies of water such as rivers, streams or lakes is also important, as it is key in preventing larger floods. The same applies to reservoirs and dams. Such monitoring also provides up-to-date information on fresh water levels, to help manage dwindling drinking water resources.

COMPACT RADAR SENSOR

One argument in favour of radar-based level measurement technology is its robustness and reliability – radar level sensors are thus not affected by ambient conditions. Until seven years ago, however, their use was limited to extremely demanding applications, like in the oil and gas industry, due to their price and size. In the meantime, the acquisition costs are a lot less, allowing the sensors to be used for applications in civil infrastructure. This is thanks to VEGA, who has perfected radar level measurement through the use of 80-GHz radar technology. The technology is now attractive even for price-sensitive applications. And at the same time, it is much more accurate and lower maintenance than previous measuring methods. The reason for this is that the beam angle is only 3-deg, a result of the higher frequency of 80 GHz. This very narrow beam easily avoids obstructions and offers a high dynamic range, which is particularly effective under conditions that make measurement difficult, such as foam generation or buildup on vessel walls. Moreover, due to its small size, the compact VEGAPULS can fit practically anywhere, even in tight, contorted spaces or narrow pump shafts. No matter where it is installed, it delivers reliable measured values.

Speaking of narrow shafts and sewers: In both water and sewage networks, the protective housing of the sensor allows it to withstand a water column of up to 30 metres. It can therefore be submerged in clean or dirty water.

In addition, the radar sensor has Ex approvals for Zone 1. This means that it can be used in potentially explosive areas such as sewer shafts without the need for expensive, intrinsically-safe barriers. The fully encapsulated construction of the radar unit makes this possible.

Intelligent systems link the level readings with a central SCADA system to enable central management of all measurement data. This allows flood events to be detected at an early stage, but it also notifies of impending water shortages. Until now, such remote management was often impossible because no power supply was available to maintain the measuring process.

The compact, 80-GHz radar measuring instruments VEGAPULS C 10, 20 and 30 have the lowest power consumption of all such devices on the market. This makes them very well suited for IIOT applications.

ENERGY-AUTONOMOUS SENSORS

But VEGA goes one step further, offering battery-powered solutions for smart city applications. VEGAPULS Air is a battery-powered, autonomous radar level sensor that takes the characteristics of 80-GHz radar and adds the capabilities of data transmission with LTE-M and NB-IoT. These standards are designed to optimise useful load, transmission time and power consumption. The future-proof design allows the sensor values to be transmitted directly to an IoT database.

LoRa – an acronym for Long Range Low Power Radio Standard – provides for the use of a wireless network to collect this data. Sensors operating with LoRa can relay information to gateways located up to 15 km away. The ability of a LoRa gateway to collect the data of multiple sensors over long distances makes it the ideal solution for smart cities and industries that operate their own LoRa network.

Manufacturers like VEGA provide a highly secure network via their certified gateways and databases. Equipped with ISO 27001 and SOC2 certification, these databases securely store data from any sensor source. The information is accessed through secure APIs or OPC UA.

The use of intelligent sensors to retrieve measurement data via a Wide Area Network makes it possible to analyse even large amounts of information with intelligent machine learning methods.

OUTLOOK

With the introduction of low-cost, intelligent and energy-autonomous sensors, it is now possible to create a huge pool of data that can be used to model and simulate drinking water and wastewater flows. This helps operators make better decisions. Events like blockages or leaks in sewer networks can be predicted just as well as imminent flooding due to heavy rainfall. What is more, regular, scheduled servicing can be replaced with needs-based servicing in order to maintain the infrastructure more efficiently and cost-effectively. Although it will never be possible to change the weather, operators will, thanks to the database, be better equipped to take suitable countermeasures at an early stage in a developing hazard.