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Abstract: This article examines the mechanisms for cross-border interchange of the regulating reserves (RRs), i.e., the imbalance-netting process (INP) and the cross-border activation of the RRs (CBRR). Both mechanisms are an additional service of frequency restoration reserves in the power system and connect different control areas (CAs) via virtual tie-lines to release RRs and reduce balancing energy. The primary objective of the INP is to net the demand for RRs between the cooperating CAs with different signs of interchange power variation. In contrast, the primary objective of the CBRR is to activate the RRs in the cooperating CAs with matching signs of interchange power variation. In this way, the ancillary services market and the European balancing system should be improved. However, both the INP and CBRR include a frequency term and thus impact the frequency response of the cooperating CAs. Therefore, the impact of the simultaneous operation of the INP and CBRR on the load-frequency control (LFC) and performance is comprehensively evaluated with dynamic simulations of a three-CA testing system, which no previous studies investigated before. In addition, a function for correction power adjustment is proposed to prevent the undesirable simultaneous activation of the INP and CBRR. In this way, area control error (ACE) and scheduled control power are decreased since undesired correction is prevented. The dynamic simulations confirmed that the simultaneous operation of the INP and CBRR reduced the balancing energy and decreased the unintended exchange of energy. Consequently, the LFC and performance were improved in this way. However, the impact of the INP and CBRR on the frequency quality has no unambiguous conclusions.
Keywords: frequency quality, load-frequency control, regulating reserves, cross-border interchange, cross-border activation
Published in DKUM: 16.06.2025; Views: 0; Downloads: 0
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Abstract: This paper analyzes the influence of inverter-interfaced distributed generations’ (IIDGs) response during transmission network faults. The simplest and safest solution is to switch IIDGs off during network faults without impacting the network voltages. A more elaborate and efficient concept, required by national grid codes, is based on controlling the IIDGs’ currents, involving positive- and negative-sequence voltage measured at the connection point. In this way the magnitude and phase of the injected currents can be adjusted, although the generated power will depend on the actual line voltages at the connection point. Therefore, an improved concept is proposed to adjust IIDGs’ fault current injection through the required active and reactive power, employing the same voltage characteristics. The proposed, i.e., power-based concept, is more definite than the currentbased one, since the required power will always be generated. The discussed concepts for the fault current injection by IIDGs were tested in different 110-kV networks with loop and radial topologies, and for different short-circuit capabilities of the aggregated network supply. Based on extensive numerical calculations, the power-based concept during transmission networks faults generates more reactive power compared to the current-based concept. However, the voltage support by IIDGs during transmission networks faults, regardless of the concept being used, is influenced mainly by the short-circuit capability of the aggregated network supply. As regards distance protection operation, it is influenced additionally by the network topology, i.e., in radial network topology, the remote relay’s operation can be delayed due to a largely seen impedance.
Keywords: distributed generation, fault current injection, voltage support, distance protection, transmission network faults
Published in DKUM: 16.06.2025; Views: 0; Downloads: 0
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Abstract: E-šport je v zadnjem desetletju doživel izjemen porast priljubljenosti in gospodarskega vpliva, kar ga postavlja v središče zanimanja številnih industrij, vključno s turizmom. Ta diplomska naloga preučuje potencial e-športnega turizma v Sloveniji, ki ima kljub svoji majhnosti dobro razvito infrastrukturo, visoko stopnjo digitalizacije in ugoden geografski položaj v osrčju Evrope. Raziskava analizira globalne trende v e-športu in hkrati preučuje specifične priložnosti ter izzive, s katerimi se sooča Slovenija kot možna destinacija za gostovanje e-športnih dogodkov na mednarodni ravni. Poleg pregleda trenutnega stanja in trendov v industriji naloga ponuja konkretne predloge za organizacijo in razvoj e-športnih dogodkov v Sloveniji, pri čemer se osredotoča na možnosti za spodbujanje lokalnega gospodarstva, ustvarjanje novih delovnih mest in povečanje mednarodne prepoznavnosti države. Prav tako naloga raziskuje, kako bi lahko Slovenija z vzpostavitvijo trajnostnega modela e-športnega turizma prispevala k dolgoročnemu turističnemu razvoju in gospodarski rasti, s čimer bi se država uveljavila kot pomemben igralec na globalnem e-športnem prizorišču.
Keywords: e-šport, turizem, razvoj, Slovenija, dogodki
Published in DKUM: 05.06.2025; Views: 0; Downloads: 2
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Abstract: Interpenetrating phase composites (IPC) are materials with two or more mutually continuous, interconnected phases. This structure allows each phase to retain its properties, while together they exhibit enhanced synergistic properties. In this work, polymer-metal IPCs with Triply Periodical Minimal Surface (TPMS) structures were fabricated and tested for their mechanical properties at different impact velocities (ranging from 0.1 mm/s to 250 m/s). Samples. The samples comprise a stainless steel reinforcement phase and two polymeric matrices (silicone and epoxy). Computed tomography was used to evaluate the internal structure and the fabrication quality. The results showed that the samples were thoroughly infiltrated with polymeric filler, achieving a high degree of homogeneity in the composite. The compression tests of silicone-filled IPCs showed an increase in stiffness. Still, the Specific Energy Absorption (SEA) was not improved due to the non-optimal stiffness ratio between the polymeric matrix and the metallic reinforcement phase. However, using epoxy as the matrix resulted in the SEA enhancement of 38 %. This is attributed to the interlocking mechanism between the two phases, which improved the macroscopic mechanical properties. The compression tests showed significant strain rate hardening due to the base material’s strain rate sensitivity and the inertia effects.
Keywords: TPMS, interpenetrating phase composite, polymer filler, hybrid structure, experimental testing, mechanical properties, strain rate effect
Published in DKUM: 26.05.2025; Views: 0; Downloads: 3
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Abstract: V diplomskem delu smo analizirali dejavnike uporabniške izkušnje, ter vpliv dostopnosti na njeno celovitost v digitalnih produktih. Raziskali smo, kako dostopnost izboljšuje izkušnjo za vse uporabnike, še posebej pa za tiste z omejitvami. Razvili smo prototip mobilne spletne trgovine za prehranske dodatke, pri čemer smo upoštevali smernice WCAG za zagotavljanje dostopnosti. Testiranje uporabnikov različnih starostnih skupin je pokazalo, očitno degradacijo vidnih, kognitivnih in motoričnih sposobnosti povezanih s starostjo ter, da je naš prototip dostopen in uporaben za uporabnike vseh starostnih skupin, saj nismo zaznali večjih točk trenja. Ugotovili smo, da dostopnost bistveno izboljša uporabniško izkušnjo, predvsem za uporabnike z ovirami.
Keywords: dostopnost, uporabniška izkušnja, prototip, spletna trgovina, uporabniki z ovirami
Published in DKUM: 08.05.2025; Views: 0; Downloads: 10
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