Hosting Capacity Optimization in Modern Distribution Grids

The availability of distributed renewable energy resources and the anticipated increase in new types of loads are changing the way electricity is being produced and supplied to consumers. This shift is moving away from a network delivering power solely from centralized power plants towards a decentralized network which supplements its power production by incorporating local distributed generators (DGs). However, the increased integration of DGs into existing distribution networks is impacting their behavior in terms of voltage profile, reliability, and power quality. To determine the maximum amount of DG that distribution grids can accommodate the concept of hosting capacity is introduced. The distribution grid hosting capacity is defined as the amount of new production or consumption that can be added to the grid without adversely impacting the reliability or voltage quality for other customers. The study of the hosting capacity is commonly accomplished by simulating power flow for each potential placement of DG while enforcing operating limits (e.g. voltage limits and line thermal limits). Traditionally, power flow is simulated by solving full nonlinear AC power flow equations for each potential configuration. Existing methods for computing hosting capacity require extensive iterations, which can be computationally-expensive and lack solution optimality. In this dissertation, several approaches for determining the optimal hosting capacity are introduced. First, an optimization-based method for determining the hosting capacity in distribution grids is proposed. The method is developed based on a set of linear power flow equations that enable linear programming formulation of the hosting capacity model. The optimization-based hosting capacity method is then extended to investigate further increasing hosting capacity by also optimizing network reconfiguration. The network reconfigurations use existing switches in the system to increase allowable hosting capacity without upgrading the network infrastructure. Finally, a sensitivity-based method is described which more efficiently obtains the optimal hosting capacity for larger distribution systems. The proposed methods are examined on several test radial distribution grids to show their effectiveness and acceptable performance. Performance is further measured against existing iterative hosting capacity calculation methods. Results demonstrate that the proposed method outperforms traditional methods in terms of computation time while offering comparable results

Flessibilità nelle reti di distribuzione e regole di mercato: scenari e valutazioni economiche

Questa tesi di laurea ha avuto come obiettivo quello di studiare il funzionamento di un mercato locale per la gestione della flessibilità distribuita in una rete di distribuzione in media tensione. Nel dettaglio si sono voluti studiare i meccanismi di fornitura dei servizi flessibili da parte degli utenti finali (produttori e consumatori), atti alla regolazione delle tensioni nodali e alla risoluzione delle congestioni nella rete di riferimento. L’analisi si è focalizzata su due diversi approcci: un primo approccio di ottimizzazione tecnico-economica dove l’obiettivo è stato quello di minimizzare i costi di gestione sostenuti dal DSO favorendo la fornitura da parte degli utenti con il miglior rapporto efficienza-economicità e un secondo approccio di ottimizzazione del mercato, dove si è cercata una soluzione che non agevoli alcun utente su base tecnica, ma favorisca uno scenario competitivo esclusivamente sulla base dei prezzi di offerta dei servizi. L’ottimizzazione del mercato ha portato poi ad individuare diverse soluzioni per la risoluzione contemporanea di congestioni e problemi di tensione, le quali sono state analizzate e confrontate sotto aspetti funzionali e valutazioni economiche.This thesis aimed to study the operation of a local market for the management of distributed flexibility in a medium-voltage distribution network. In detail, the aim was to study the mechanisms for the provision of flexible services by end users (producers and consumers), suitable for the regulation of nodal voltages and the resolution of congestion in the reference network. The analysis focused on two different approaches: a first approach of technical-economic optimization where the objective was to minimize the operating costs incurred by the DSO by favoring provision by users with the best efficiency-economic ratio and a second approach of market optimization, where a solution was sought that does not facilitate any user on a technical basis, but favors a competitive scenario purely on the basis of service offer prices. The market optimization then led to the identification of several solutions for solving congestion and voltage problems simultaneously, which were analyzed and compared under functional aspects and economic assessments