Tiny signals can prevent major accidents

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Hossein Ehya used a specially built model generator to conduct experiments in NTNU’s SmartGrid lab. Credit: Juliet Landrø/HydroCen

By listening to the magnetic fields of electric machines, faults can be detected that could prevent potential disasters with electric vehicles. The new method could also save electricity producers large sums of money.

“What we do can be compared to what a doctor does, where the electric motor is our patient. In the same way that a doctor performs an electrocardiographic examination of the patient’s heart, we collect the signals from the machine and analyze them. “, explains Hossein. Ehya, researcher at HydroCen and NTNU.

A power failure can cause an accident

Imagine driving your Tesla down the highway, maybe 100 or 110 kilometers per hour. Suddenly your car starts to accelerate, the speed increases and you are no longer able to control the car. Then you crash into a rock wall.

The dramatic consequences of an electric motor failure are easy to imagine.

“Several accidents like this have happened since 2010. Imagine what could happen if you had this kind of failure in an electric airliner. Politicians are pushing for all-electric planes, and Norway is one of the countries leaders in electrification. If an engine in an electrically powered aircraft suddenly shuts down, in the worst case, the aircraft could crash,” says Ehya.

Study of generators in hydroelectric power plants

Ehya holds a master’s degree from the University of Tehran, but chose Norway and NTNU to continue her research in electric motor monitoring and diagnostics. Ehya’s PhD work at HydroCen, an eco-friendly energy research center in Trondheim, has the potential to create new technology workplaces related to electrification and greening.

Tiny signals can prevent major accidents

Here, the signals indicate that one of the coils has a short circuit. The resistance and length of the bar showing the broken coil is reduced. Credit: Norwegian University of Science and Technology

“What we need is affordable equipment that is easy to use and can detect failures preemptively,” says Ehya.

So far, large generators at Norwegian hydropower plants have been researched into machine learning and troubleshooting using magnetic field measurements. Breakdowns and damage inside plant generators can result in significant expense for Norwegian hydropower plants, when they are forced to interrupt production to find and repair faults.

As a medical check for electric motors

Hydroelectric power plant generators were often installed decades ago without understanding the zero state of the machine, that is, how it should operate before an error occurs. This makes it difficult to troubleshoot with today’s diagnostic tools, says Ehya.

“Many methods for finding faults in generators require knowing how they behave when they are ‘healthy’. But often such precise analyzes are not carried out before the generators are commissioned. For example, we can measure the vibrations in the generator and thus determine that something is wrong, but we cannot say exactly what is wrong,” he said.

Any number of things can go wrong inside an electric motor. You can get a short in the stator, the stationary part of the motor where the coils are, or in the rotor itself, the moving part that together with the stator creates the magnetic field in the motor. The rotor may become crooked or other vital components may suffer mechanical damage.

“An electric motor gives us no sign of failure, until it breaks down. That is why periodic inspections must be carried out. The machine must be stopped to check for faults and carry out maintenance, but if the defect can if not found during inspection, the machine fails,” says Ehya.

Tiny signals can prevent major accidents

Signals of a “healthy” generator. Each bar shows signals from one of the eight stator coils. The eight columns inside the red frame thus show a complete mechanical revolution of the rotor. Credit: Norwegian University of Science and Technology

saving time and money

With current methods, the machine must either be disassembled to install an internal sensor or inspected using external measuring equipment.

Installing a sensor is a big job that power plant owners are often not very keen on doing. External inspections measure vibrations or voltage variations, which can tell us if something is wrong or not, but the equipment is not very sensitive and is often used when it is already too late.

“With our method, we use a very affordable sensor that can be mounted in minutes outside the machine. The sensor measures the machine’s magnetic field and analyzes it. Researchers can then determine if the machine is ‘ healthy’ or shows symptoms of failure. They can also identify the problem,” says Ehya.

According to HydroCen researchers, the new technology can save electricity producers large sums of money. The costs of shutting down and dismantling a generator set can quickly add up to tens of thousands of euros, while running the risk of losing revenue when production stops.

With Ehya’s sensors, the machine can instead be monitored and the data analyzed in the cloud using artificial intelligence.

Norwegian manufacturing

So far, the new method has been tested on generators at two Norwegian hydropower plants, but Ehya and his colleagues expect it to be useful in the automotive and transport industry, on Norwegian oil rigs as well as for wind energy.

The project is now in a commercialization phase where the research team is collaborating with Rolls Royce, IKM, Statkraft and Captiva. And Ehya has no intention of withdrawing the patents from Norway.

“The Research Council of Norway has donated 500,000 euros to enable us to continue our work. This is Norwegian oil money and Norwegian taxpayer money. If my work here can enable us to create jobs and income in Norway, I will. It’s my way of being able to give back a little for the support I’ve received here,” says Ehya.

Provided by Norwegian University of Science and Technology

Quote: Tiny Signals Can Prevent Major Accidents (November 15, 2022) Retrieved November 16, 2022 from https://techxplore.com/news/2022-11-miniscule-major-accidents.html

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