Planning and operation of a transmission grid under the N-1 criterion
Since approximately 2010, the power sector has been transitioning from a centralized, unidirectional model to a distributed, prosumer-driven system. This transformation originates from a need of higher reliability, power quality, market efficiency, and decarbonization needs. The smart grid emerged a...
| Autor: | |
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| Tipo de recurso: | tesis de maestría |
| Fecha de publicación: | 2025 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:upcommons.upc.edu:2117/445628 |
| Acceso en línea: | https://hdl.handle.net/2117/445628 |
| Access Level: | acceso abierto |
| Palabra clave: | Electric power transmission Electric power distribution Multiagent systems Energia elèctrica -- Transmissió Energia elèctrica -- Distribució Sistemes multiagent Àrees temàtiques de la UPC::Enginyeria elèctrica |
| Sumario: | Since approximately 2010, the power sector has been transitioning from a centralized, unidirectional model to a distributed, prosumer-driven system. This transformation originates from a need of higher reliability, power quality, market efficiency, and decarbonization needs. The smart grid emerged as an advanced approach: integrating sensing technologies, secure bidirectional communication, and distributed control to build new market structures while enhancing resilience and reducing emissions. However, the integration of large-scale distributed energy, microgrids, and electric vehicle charging infrastructure triggers rapid power fluctuations and bidirectional power flows, posing challenges to voltage/frequency stability. To address these challenges, smart grids employ Multi-Agent System (MAS) control, where autonomous local agents actively regulate inverters, transformer taps, and loads to achieve fault isolation and parallel optimization. To correcly coordinate all these agents, precise power flow analysis has become critical to avoid congestion, where it must ensure the satisfaction of the N-1 criterion, that ensures the grid meets voltage and thermal limits during any single-point equipment failure. This paper models a 16-node 110kV Catalan transmission grid, that includes a 190MW nuclear power plant, four major load nodes, one external grid backup node, and four 20kV subnetworks connected via step-down transformers). As depicted in the base map, the network exhibits a radial configuration, centered at the Tarrega node, that expands toward Manresa-Terrassa, Lleida, Igualada, and Montblanc/Vandellós. The grid was constructed using PandaPower to solve AC power flows (employing timeseries powerflow) for various scenarios. Monte Carlo N-1 fault analysis was implemented: each simulation randomly selected one component (line or transformer) to simulate a fault, followed by recalculation of power flows. System outage duration was accumulated based on assumed repair/switching times, and interrupted energy was quantified using interruption penalty factors. Three upgrade strategies were evaluated: (1) Adding a 33 km high-voltage line between Terrassa and Igualada; (2) Adding two lines, one of 90 km Lleida-Vandelòs, and another of 80 km Terrassa-Montblanc; (3) Integrating new renewable energy (50 MW solar, 100 MW wind) with supporting interconnectors. The baseline analysis revealed critical vulnerabilities: Critical transmission corridors are severely overloaded (e.g., Terrassa-Manresa line at 99.9%), and grid voltage stability under normal conditions is low: with an average voltage stability of 33% over the year. Moreover, N-1 fault tests show that failures on lines cause widespread blackouts, spiking the line loading or dragging the voltage to abnormal values. Annual power losses due to outages represents a cost that is negligible compared to import expenses, indicating that enhancing resilience is more critical than short-term cost savings. Each upgrade delivered significant benefits: Upgrade 1 alleviated pressure on both the TerrassaManresa-Tarrega corridor, and the adjacent lines. Overall voltage stability was also significantly improved, and blackouts were avoided. Upgrade 2 eliminated blackouts, and boosted stability to approximately 74.2%. Upgrade 3 significantly reduced external energy demand, achieved near-100% grid voltage stability, and completely solved line overloading problem. Finally, an economic analysis was performed, where although the payback period is long, the technical and societal value is evident: the N-1 standard strengthens the grid with ultimate resilience, where security and public reliability must prevail over economic considerations. |
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