Vjerojatnost otočnoga pogona fotonaponske elektrane s više mrežnih izmjenjivačkih jedinica priključene na mrežu srednjega napona

doctoral thesis

• Title (english): Island operation probability for multi-inverter photovoltaic power plant connected to medium voltage grid
• Author: Mihovil Ivas
• Mentor: Ante Marušić (mentor)
• Committee member: Ante Marušić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Electrical Engineering and Computing; (Department of Energy and Power Systems); Zagreb
• Defense date and country: 2019, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Electrical Engineering; Power Engineering
• Universal decimal classification (UDC): 621.3 - Electrical engineering

Abstract

Otočni pogon distribuiranog izvora može se javiti u slučaju podudaranja proizvodnje distribuiranog izvora i potrošnje konzuma lokalne mreže u trenutku odvajanja takvog lokalnog sustava od ostatka mreže. Apsolutno pouzdane metode zaštite od pojave takvog pogona jedino su neekonomične komunikacijske metode temeljene na sustavu daljinskog vođenja. U ovom radu obrađuje se vjerojatnosno kvantificiranje pojave takvog neželjenog otočnog pogona s naglaskom na određeni tip elektrana - fotonaponske elektrane sastavljene od više izmjenjivača koja se priključuje na mrežu srednjeg napona. Ovaj specifičan tip elektrana ima nekoliko osobina koje ga čine različitim od drugih klasičnih tipova izvora na temelju čega se i pristup istraživanju otočnog rada ovog tipa elektrana mora razlikovati. U radu se prvo analizira struktura tipične fotonaponske elektrane sastavljene od više izmjenjivača koja se priključuje na mrežu srednjeg napona. Teoretski su određeni doprinosi ukupnoj radnoj i jalovoj snazi svih elemenata od kojih je elektrana sastavljena. Definiran je P-Q dijagram svih mogućih radnih točaka elektrane na mjestu priključka na mrežu te provedena usporedba mjerenja izvršenih na stvarnoj elektrani s izračunatim vrijednostima, analiza i korekcija modela. Zatim je predložena metodologija za izračun vjerojatnosti pojave otočnog rada. Pri proračunu vjerojatnosti definiranom metodom koriste se prije definirani P-Q dijagram elektrane, podaci o konfiguraciji mreže, statistički pogonski parametri mreže i potrošača te definirane krivulje gustoće vjerojatnosti snaga proizvodnje fotonaponske elektrane i potrošnje lokalne mreže modelirane trokutastom razdiobom koja je predložena analizom literature i dostupnih podataka iz mjerenja u mreži operatora distributivnog sustava. Metoda je primjenjiva na najčešće korištene pasivne metode zaštite od otočnog rada, za koje je u radu potom analizirana zona neprepoznavanja. Proračun vjerojatnosti u ovisnosti o primjenjenoj funkciji zaštite je proveden na primjeru stvarne elektrane i lokalne mreže, na temelju čega su izvedeni zaključci.

Abstract (english)

Island operation of distributed generation sources is encountered when there is a balance of generation and load power in local grid in the moment of disconnection from the main grid. Absolutely reliable protection methods in such case are only remote operation system based communication methods which are non-economical. This dissertation deals with probability quantification for the occurrence of such unwanted island operation, with emphasis on a particular type of power plant - a photovoltaic power plant consisting of multiple inverter units connected to the medium voltage power grid. This particular type of power plant has several characteristics which make it different from other classic types of energy sources, for which reasons also the approach to the research of island operation of this type of power plants has to differ from classical approach. First topic of research is the analysis of the structure of a typical photovoltaic power plant consisting of multiple inverter units connected to the medium voltage power grid. Theoretical contributions of all power plant elements to the total active and reactive power are determined. P-Q diagram of all possible operation points of the power plant, at the point of connection to the grid, is determined, then a comparison of calculated values with the actual measurements carried out on the case study power plant is performed, followed by analysis and correction of the model. Following that, the methodology is proposed for calculating the probability of island operation. For the probability calculation the following data is used: predetermined P-Q diagram of the power plant, network configuration data, statistical operating parameters of the grid and of the consumers, and the probability density curves for photovoltaic power plant generation power and load power of the local grid consumers, modeled with triangular probability distribution proposed from literature analysis and available data from measurements in the distribution system operator grid. The method is applicable to the most commonly used passive methods of island protection, for which the non-detection zone was then analyzed. The probability calculation for the applied protection functions was performed on the case study power plant and the local grid, on the basis of which conclusions were drawn.

• Keywords: otočni pogon; vjerojatnosna analiza rizika; distribuirani izvori; izmjenjivač; sunčana elektrana; pogonska karta; zaštita od otočnog pogona; vjerojatnost otočnog pogona
• Keywords (english): island operation; probabilistic risk analysis; distributed generation source; inverter; solar power plant; operation chart; island protection; island protection probability
• Language: croatian
• URN:NBN: urn:nbn:hr:168:515374
• Study programme: Title: Electrical Engineering and Computing; Study programme type: university; Study level: postgraduate; Academic / professional title: Doktor znanosti elektrotehnike i računarstva (Doktor znanosti elektrotehnike i računarstva)
• Type of resource: Text
• Extent: 208 str. ; 30 cm
• File origin: Born digital
• Access conditions: Open access
• Created on: 2020-01-21 10:01:52