Nowadays, distribution networks are being subjected to an increasing penetration of active users on both low and medium voltage levels, typically based on small size power plants from renewable energy sources (known also as distributed generation). Distribution grids are designed for providing electricity to the customers and could take some advantages from the renewable energy sources production such as sustainability, less maintenance and low carbon emissions. However, upward trends of installing dispersed generators cause some power quality challenges for distribution system operators, such as harmonics, voltage regulation issues, interface protection problems and power quality in general. Therefore, the focus of the present thesis is on appropriate management of distributed generation. However, as available electrical network data in some power system networks are limited, it is required to estimate the unknown grid parameters using available measurements data such as active power, reactive power and voltage magnitudes. Then, the evaluation of maximum active power injection to the grid by dispersed generator (named Hosting Capacity), its applications and its voltage control are studied. To do so, a novel procedure to estimate the single bus hosting capacity even in case of uncertainties in grid parameters or lack of data is presented, named Bricks approach. This approach could be used when the possibility of data collection is very low or complex. Then, multi-generator hosting capacity is evaluated using the combination of Bricks approach and a suited Monte Carlo procedure. In addition, electric vehicle integration as the other discussed application in this thesis is looked into by Monte Carlo simulation for different charging processes. At the end, to increase the hosting capacity a novel procedure based on optimal power flow is proposed. The goal is to avoid over and under voltages violations and preserve the grid efficiency. Actually, the procedure is proposed in order to optimally set-up the standard voltage control setting, i.e. to be directly integrated into the already in place voltage regulators. All of the mentioned simulations in this thesis work are coded in MATLAB and then validated for a real-life case studies in Italy and Tanzania.
Oggigiorno, le reti di distribuzione sono soggette a una crescente penetrazione di utenti attivi sia in bassa che media tensione, basati in genere su impianti di produzione di piccole dimensioni alimentati da fonti rinnovabili (noti anche come generazione distribuita). Le reti di distribuzione sono progettate per fornire elettricità ai consumatori e potrebbero trarre alcuni vantaggi dalla produzione di energia rinnovabile, per esempio in termini di sostenibilità, minore manutenzione e ridotte emissioni di anidride carbonica. Tuttavia, la tendenza all’aumento di generazione diffusa causa alcuni problemi di power quality per gli operatori del sistema di distribuzione, come presenza di armoniche, difficoltà di regolazione della tensione, problemi di coordinamento delle protezioni e qualità dell’alimentazione in generale. Pertanto, il focus della presente tesi è la gestione appropriata della generazione diffusa. Tuttavia, poiché i dati disponibili sulla rete elettrica in alcune parti del sistema di generazione sono limitati, è necessario stimare i parametri della rete non noti utilizzando i dati misurati a disposizione come potenza attiva, potenza reattiva e tensione. Viene quindi valutata la massima potenza attiva che può essere immessa in rete dalla generazione distribuita (denominata Hosting Capacity), le sue applicazioni e il relativo controllo di tensione. Per fare ciò, viene presentata una nuova procedura per stimare l’hosting capacity di un nodo, anche in caso di incertezza dei parametri di rete o mancanza di dati, chiamata approccio Bricks. Questo può essere utilizzato quando la possibilità di raccolta dei dati è molto ridotta o risulta complessa. L’hosting capacity multi-generatore viene valutata utilizzando la combinazione dell’approccio Bricks e di una procedura Monte Carlo appropriata. Inoltre, l’integrazione di veicoli elettrici viene discussa in questa tesi come ulteriore applicazione e diversi processi di ricarica sono esaminati tramite il metodo Monte Carlo. In conclusione, viene proposta una nuova procedura basata sull’optimal power flow, al fine di aumentare l’hosting capacity. L’obiettivo è evitare violazioni di sovratensione e sottotensione e preservare l’efficienza della rete. La procedura viene di fatto proposta per impostare in modo ottimale il setting di tensione standard, per essere quindi integrata direttamente nei regolatori di tensione già presenti. Tutte le simulazioni citate in questo lavoro di tesi sono codificate in MATLAB e convalidate per casi di studio reali in Italia e Tanzania.
Renewable energies integration on distribution grid
MIRBAGHERI GOLROODBARI, SAYEDEH MINA
Abstract
Nowadays, distribution networks are being subjected to an increasing penetration of active users on both low and medium voltage levels, typically based on small size power plants from renewable energy sources (known also as distributed generation). Distribution grids are designed for providing electricity to the customers and could take some advantages from the renewable energy sources production such as sustainability, less maintenance and low carbon emissions. However, upward trends of installing dispersed generators cause some power quality challenges for distribution system operators, such as harmonics, voltage regulation issues, interface protection problems and power quality in general. Therefore, the focus of the present thesis is on appropriate management of distributed generation. However, as available electrical network data in some power system networks are limited, it is required to estimate the unknown grid parameters using available measurements data such as active power, reactive power and voltage magnitudes. Then, the evaluation of maximum active power injection to the grid by dispersed generator (named Hosting Capacity), its applications and its voltage control are studied. To do so, a novel procedure to estimate the single bus hosting capacity even in case of uncertainties in grid parameters or lack of data is presented, named Bricks approach. This approach could be used when the possibility of data collection is very low or complex. Then, multi-generator hosting capacity is evaluated using the combination of Bricks approach and a suited Monte Carlo procedure. In addition, electric vehicle integration as the other discussed application in this thesis is looked into by Monte Carlo simulation for different charging processes. At the end, to increase the hosting capacity a novel procedure based on optimal power flow is proposed. The goal is to avoid over and under voltages violations and preserve the grid efficiency. Actually, the procedure is proposed in order to optimally set-up the standard voltage control setting, i.e. to be directly integrated into the already in place voltage regulators. All of the mentioned simulations in this thesis work are coded in MATLAB and then validated for a real-life case studies in Italy and Tanzania.File | Dimensione | Formato | |
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Thesis_Mirbagheri_SecondSubmission.pdf
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Descrizione: THESIS OF RENEWABLE ENERGIES INTEGRATION ON DISTRIBUTION GRID
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https://hdl.handle.net/10589/146134