diplomsko delo
Dušan Golubović (Author), Boštjan Blažič (Mentor)

Abstract

Per aspera ad astra, tako bi lahko opisali način, kako so električna vozila (EV) prišla do mesta, kamor sodijo danes. To mesto, kjer so danes, je sinonim za tehnologijo, inovativnost in luksuz v svetu avtomobilizma, ki je iz istih razlogov za marsikoga še vedno nedosegljiv. Po eni strani je ta tehnologija v veliki meri odvisna od elektroenergetskega sistema (EES), po drugi strani pa je stanje v sistemu odvisno od števila in razporeditve vozil. Zato je stabilnost in zanesljivost energetskega sistema izjemnega pomena tako za EV kot tudi za vse druge porabnike. V ta namen bodo v diplomskem delu obravnavane različne strategije polnjenja in praznjenja EV, da bi pridobili vpogled v vpliv EV na stanje EES. V sklopu diplomskega dela bodo obravnavane različne strategije polnjenja in praznjenja EV. Na začetku si bomo ogledali obratovanje omrežja v primeru nenadzorovanega polnjenja. Temu bo sledil ogled ugodnosti, ki jih prinaša pametno oz. nadzorovano polnjenje. Pregled različnih strategij polnjenja bomo zaključili z uporabo koncepta Vehicle-to-Grid (V2G), ki predstavlja korak dlje v primerjavi s pametnim polnjenjem. Za ta namen bodo simulacije izvedene v programskem okolju Matlab s posredno uporabo OpenDSS-a. Na podlagi statističnih podatkov, kot so profili, trajanje in dolžine voženj, bomo določili bremenski diagram EV. Simulacije bodo izvedene na reprezentativnemu vzorcu nizkonapetostnega omrežja, vendar tako dobljene rezultate v nadaljevanju lahko posplošimo na širše območje. Omrežje je sestavljeno iz 97 odjemalcev in je napajano s transformatorjem TP 21/0.42 kV. Izvedli bomo več simulacij za različne strategije polnjenja in na podlagi tega ocenili vpliv EV na EES ter kako koncept V2G pomaga pri razbremenjevanju omrežja. Kot rezultat diplomskega dela pričakujemo nabor različnih rezultatov, ki na razviden način ponazarjajo oz. prikazujejo dogajanja v omrežju pri različnih strategijah polnjenja. V primeru nenadzorovanega polnjena oz. ko se porabniki enostavno priklapljajo na omrežje in polnijo EV, kadarkoli to želijo, pričakujemo dodatno obremenitev transformatorja. Če rezultat posplošimo na širše območje, bi to pomenilo, da je celotno omrežje preobremenjeno, kar lahko v skrajnem primeru privede do njegovega izpada. Po drugi strani bomo v primeru nadzorovanega polnjenja sledili konceptu pametnega polnjenja, kar pomeni, da bomo porabnike ‚‚spodbudili‘‘, da EV polnijo izključno v nočnih urah, ko je omrežje neobremenjeno. Takrat pričakujemo, da dnevna in popoldanska konica ostaneta na enaki višini, dokler se ostali del diagrama ne bo ustrezno povečal. Predvsem imamo v mislih del, ki reprezentira potrebe po energiji od 22. do 6. ure. Zadnji primer se bo nanašal na uporabo koncepta V2G. Takrat pričakujemo dokaj enak odjem tekom dneva, kar dosežemo z glajenjem. Z drugimi besedami, vozila se bodo polnila v časih, ko so razmerje v omrežju dokaj ugodne, kar pomeni, da se bo diagram porabe za te dele dneva povečal. Po drugi plati se bodo vozila v časih konice praznila in energijo vračala proti omrežju nazaj. V tem primeru omrežje EV vidi kot dodatne izvore in ne porabnike. Posledično se bosta dnevna in popoldanska konica znižali v določeni meri in na ta način bomo razbremenili omrežje. S tem dosežemo, da je diagram porabe tekom dneva manj ali več konstanten, medtem ko dejanska potreba po energiji precej variira.

Keywords

električna vozila;elektroenergetski sistemi;nizkonapetostna omrežja;polnjenje;V2G;univerzitetni študij;Elektrotehnika;diplomske naloge;

Data

Language: Slovenian
Year of publishing:
Typology: 2.11 - Undergraduate Thesis
Organization: UL FE - Faculty of Electrical Engineering
Publisher: [D. Golubović]
UDC: 629.331-83:621.315(043.2)
COBISS: 122281475 Link will open in a new window
Views: 16
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Other data

Secondary language: English
Secondary title: Electric vehicle charging strategies
Secondary abstract: Per aspera ad astra. How electric vehicles (EVs) got to where they are today could be explained with that one phrase. This place, where they are today, is synonymous with technology, innovation and luxury in the motoring world, which, for the same reasons, is still out of reach for many. On the one hand, this technology is largely dependent on the electric power system, and on the other, the state of the system largely depends on the number and distribution of vehicles. Therefore, the stability and reliability of the energy system is extremely important, both for EVs and for all other consumers. For this purpose, the thesis will discuss different EV charging and discharging strategies in order to gain insight into the impact of EVs on the state of the grid. At the beginning, we will look at the operation of the network in the case of uncontrolled charging. This will be followed by a look at the benefits brought to us by smart (controlled) charging. We will conclude the overview of different charging strategies by using the Vehicle-to-Grid (V2G) concept, which represents a step further compared to smart charging. For this purpose, the simulations will be carried out in the Matlab environment, with the indirect use of OpenDSS. Based on statistical data such as profiles, duration and length of trips, we will determine the load diagram of the EV. The simulations will be performed on a representative sample of the low- voltage network, but the results obtained in this way can later be generalized to a wider area. The network consists of 97 consumers and is powered by a distribution transformer with 21/0.42 kV ratio. We will perform several simulations for different charging strategies and based on this, we will evaluate the impact of EVs on the power system and how the V2G concept helps to relieve the grid. As a result of the thesis, we expect a set of different results that clearly show what happens in the network for different charging strategies. In the case of uncontrolled charging, when consumers simply connect to the grid and charge EVs whenever they want, we expect additional load on the transformer. If we generalize the result to a wider area, it would mean that the entire network is overloaded, which in the extreme case, can lead to its outage. On the other hand, in the case of controlled charging, we will follow the concept of smart charging, which means that we will "encourage" consumers to charge EVs exclusively at night, when the network is free of load. At that point we expect the day and afternoon peaks to remain at the same height, until the rest of the chart increases accordingly. Above all, we keep in mind the part which represents energy needs from 10 p.m. to 6 a.m. The last example will refer to the application of the V2G concept. At that time, we expect somewhat even consumption during the day, which is achieved by flattening. In other words, the vehicles will be charging at times when the network conditions are favorable, which means that the consumption diagram for those parts of the day will increase. On the other hand, during peak times, vehicles will discharge and return energy back to the grid. In this case, the grid sees EVs as additional sources rather than consumers. As a result, the morning and evening peaks will decrease to a certain extent and in this way, the network will be relieved. With this, we achieve that the consumption diagram is somewhat constant during the day, while the actual need for energy varies considerably.
Secondary keywords: electrical vehicles;power system;low voltage network;charging;V2G;
Type (COBISS): Bachelor thesis/paper
Study programme: 1000313
Embargo end date (OpenAIRE): 1970-01-01
Thesis comment: Univ. v Ljubljani, Fak. za elektrotehniko
Pages: XIII, 60 str.
ID: 16469408