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Master thesis: Decentralized signal processing for travelling wave detection in embedded protection devices

Publicerad 2019-12-02

Om uppdragsgivaren
ABB Grid Automation Products provides world class products for protection and control for generation, transmission and sub-transmission. The product portfolio consists of Relion 650/670 series in a wide range of products such as line protection, transformer protection, breaker protection etc. The Västerås office is the largest within ABB Grid Automation Products and spans from marketing & sales to supply management and operation as well as R&D developing hardware, embedded software and application functions for the product portfolio.

Beskrivning av examensarbetet
Overhead line and cable fast-fault clearance, together with accurate fault location, are essential for power grid operators to maximize grid availability.
For the last 30 years, CPU-based embedded devices have been the dominant solution for integrating several fault detection and localization methods into one device. A modern conventional line protection device typically includes functions such as impedance, differential current or time overcurrent protection. These devices implement their functionalities thanks to analog input data collected from one or several, local or remote, I/O modules providing A/D converted sample data.
Recent power system research suggests that fault detection and localization using travelling wave detection can complement conventional algorithms to improve its performance, as it enables significantly faster fault detection as well as more accurate fault localization. In order to detect significantly higher travelling waves, roughly a factor of 103 MHz instead of kHz, sampling frequency is required for the power grid protection algorithms mentioned above. Determining the distance travelled for the wave also sets high requirements for time accuracy of detected waves. Therefore, travelling wave applications become a new paradigm in protection devices for filter design, amount of sample data to be processed, time synchronization accuracy and bandwidth needed for data transfer.
At the same time, it is a business advantage to integrate the travelling wave methods into products together with other protection functions. The method proposed for this thesis is to decentralize feature extraction for travelling wave detection from the CPU closer to the A/D conversion. The preprocessed results are then propagated to the CPU for evaluation and later combination with other data.

Your task will be to analyze and prototype the concept for decentralizing feature extraction for travelling wave detection regarding:

- Requirements on the sampling frequency, signal accuracy and resolution after A/D conversion.
- Identify and study filters/wavelets suitable for decentralized travelling wave detection.
- Analyze and evaluate time-synchronization requirements for decentralized travelling wave detection.
- Implement an SW prototype based on the existing HW prototype.

- According to ABB master thesis standard. The majority of the thesis work is expected to be performed at ABB facilities in Västerås

Experience in one or several of the fields:
- Embedded software development in C/C++
- Signal processing
- Electronics design and A/D conversion
- Power systems protection and control

Johan Lundberg


ABB Automation Grid SA


Sista ansökningdag

Thesis PDF

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