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Voltage support in open pit mining power systems using electric drill rigs
Gomez Arguello, Juan Pablo; Pardo Galvis, Jaime Andres
The electrification of mining operations presents significant challenges in power quality, particularly in remote open-pit mines where limited grid connectivity results in reduced short-circuit capacity and increased susceptibility to voltage instability. High-power induction motor startups in drilling equipment frequently generate significant voltage sags, that compromise operational continuity and compliance with power quality standards. This thesis examines different configurations of the motor and drive system for electric drilling units and their impact on voltage profiles in mining grids. The study aims to determine how electric drillers can provide voltage support to improve grid voltage stability. A comprehensive electrical distribution grid model was developed in MATLAB/Simulink, incorporating typical mining environment loads. Critical scenarios were identified through parametric sweeps across different grid strengths to assess voltage sag depth, duration, and reactive power demand under multiple operational scenarios. Simulation results demonstrate that Active Front End (AFE) drives significantly reduce the severity of voltage sag, improve steady-state voltage profiles, and maintain system stability under weak grid conditions. When AFE control is modified to provide
dynamic reactive power compensation, additional voltage support is achieved, further mitigating voltage sags and enabling stable operation under even weaker grid conditions while maintaining voltage performance comparable to full AFE implementation. A key contribution of this work is to demonstrate that a single AFE-equipped driller with compensation capability can effectively support multiple Direct-On-Line (DOL) drillers during simultaneous operation, keeping Point-of-Common Coupling (PCC) voltages within acceptable limits without requiring full fleet AFE conversion. This selective deployment approach represents a technically robust and operationally viable solution to enhance power quality and resilience in mining electrical systems.
3D Scanning of naturally corroded steel bars. An assessment of corrosion behaviour and correlations to critical cross-sections
(2025) Das, Priyanka
The present study focuses on the effect of corrosion of steel reinforcement in reinforced concrete (RC) structures. Corrosion has a large impact on the structural performance of RC structures. A cross-section reduction of the steel bar occurs due to the oxidation of steel which unequivocally convey a non-uniform distribution of pits along the bar length. For a specific length, it is possible to identify a critical cross-section (CCS), which attains the highest loss of area. This thesis defines CCS and illustrates how the different characterizing parameters of the same can be described from the measured average corrosion level of a specific bar length.
To cover this objective naturally corroded steel bars from a real bridge situated in Stallbacka were employed. After structural testing of the edge beams of the bridge, the steel reinforcement was extracted, cut into suitable lengths, and subsequently cleaned. Thereafter the average corrosion level of each specific bar was obtained by using two different techniques, gravimetric and 3D scanning. By weight loss method accurate measurements of the average corrosion level were obtained; by 3D scanning discrete corrosion level in each cross-section was quantified. In addition, variables such as pit depth, pit length, pit width, and, corroded perimeter, were measured from the CCS by combined physical and numerical post-processing of the 3D scanning techniques. These measurements led to a precise description of the CCS.
Finally, relations between all the measured parameters to the average corrosion level were obtained, hence possible predictions of the CCS from the estimated average corrosion level of a specific bar length could be described. Furthermore, in further works, the tensile properties of the utilized steel bars can be correlated to the CCS description and later estimate the reduction of capacity of the steel bars because of the presence of corrosion.
User Experience of Electric Vehicle Energy Use and Range
Li, Annie; Palmberg, Paulina
Electric Vehicles (EVs) are rapidly gaining popularity, but with the transition from Internal Combustion Engine Vehicles (ICEVs) to EVs comes a learning curve for new users. Through internal surveys, Volvo has discovered a dissatisfaction amongst
some of their users when it comes to the range of their EVs. Range in EVs is influenced by both driver behaviour and external factors. Volvo’s existing Range Assistant interface is designed to help users understand and optimise their energy
consumption, and potentially alleviating range anxiety. However, some users find the interface difficult to interpret, leading to frustration and confusion. This project therefore aims to identify potential knowledge gaps amongst EV users regarding range estimation and energy consumption. Using a user-centred design approach, questionnaires and usability tests were conducted iteratively to explore user needs and challenges. Based on the findings from the iterations, a list of 10 design recommendations to improve range assistance interfaces has been established. These recommendations cover aspects such as information visualisation, feedback, and coaching, offering guidance for enhancing user trust and understanding in EV
range estimation interfaces.
Audience engagement in immersive installations
(2025) Böckert, Julia; Ermeryd Tankred, Isabelle
Immersive installations can be defined as real-world spaces where walls and floors are covered with moving projections, combined with surrounding sounds and light, to create an immersive and multi-sensory environment [1]. Visual Arena is a platform that brings together multiple stakeholders from the XR industry, and they have observed a growing interest in exploring immersive installations in Gothenburg. This thesis is a part of Visual Arena’s feasibility study on audience engagement within such installations. The project was guided by design thinking and followed an iterative design process proposed by Visual Arena, inspired by to the well-known double diamond framework. It includes four phases: empathize, frame, experiment, and deliver. The approach resulted in the creation of a high-fidelity prototype in collaboration with Visual Arena’s partner network to facilitate the development of an immersive installation. Visitor feedback indicated that visuals, sound, and interactions contributed to a sense of engagement and immersion. While the onboarding areas helped visitors engage with the theme, they were less effective at preparing users for interactions within the immersive installation. Only a small subset of visitors identified a clear narrative, which may be a consequence of the less prominent storytelling due to technical challenges and time constraints. As a result, conclusions regarding the impact of narrative on user engagement remain ambiguous. Future work should further investigate the role of storytelling in immersive installations and evaluate the technical feasibility of implementing such installations.
Digital Fika - Designing Accessible Digital User Experiences for Older Adults
(2025) Nilsson, Anna; Svensson, Klara
This thesis explores accessibility and digital commensality through creating a set of recommendations and developing a website prototype called Digital Fika. Through an iterative process the prototype was developed and tested with a user group consisting of older adults around the ages of 70 and 80 years. The users were a bit skeptical towards Digital Fika at first, but when the concept had a more refined and responsive prototype interface they were more interested and positive towards
it. Throughout the process, a set of recommendations for how to build an accessible web page were also created. It became clear during the process that the testers were not diverse enough to create and test a broad set of accessibility recommendations, rather they fit able bodied older adults with some experience of technology and a variation of visual impairments. To further the research in this thesis, one should test the concept and accessibility guidelines with a test group with a more varied set of impairments to give a more accurate account of which accessibility recommendations are important, and more varied in cultural background to see how that affects socialization. In addition to this, one could look at the accessibility of the technology users use to interact with the website.