THE IMPACTS OF SOLAR PLANT ON POWER QUALITY

Ob množičnem vključevanju sončnih elektrarn v elektroenergetsko omrežje se postavlja vprašanje o kakovosti električne energije. Diplomsko delo obravnava vpliv na kakovost električne energije sončne elektrarne priključene na distribucijsko omrežje. Ta je različen od primera do primera, kjer so vključeni številni dejavniki s strani zasnove sončne elektrarne ter prav tako s strani distribucijskega omrežja. Pri tem ima najpomembnejšo vlogo kakovost razsmernika, moč transformatorja in impendanca omrežja. Da bi bili vplivi sončnih elektrarn na omrežje čim manjši, morajo razsmerniki izpolnjevati vrsto zahtev, ki so predpisane s standardi, kot osnovna zahteva pa velja, da mora biti tok, napetost in frekvenca sončne elektrarne skladni s parametri distribucijskega omrežja. Ker na kakovost električne energije v distribucijskem omrežju vplivajo številni dejavniki se je za ta namen vpeljal standard SIST EN 50160, s katerim je postala kakovost električne energije merljiva. Slednje smo raziskali na podlagi meritev kakovosti električne energije skladno z omenjenim standardom pred in po priključitvi sončne elektrarne. Ugotovili smo, da preučeavana elektrarna ni bistveno poslabšala kakovosti električne energije. Zaznali smo povečanje pete in sedme harmonske komponente v toku na izhodu razsmernikov, kateri nista izrazito vplivali na prispevek k obstoječim harmonikom v distribucijskem omrežju. In recent years, importance of solar power plants as a source of electric energy increased, but there are some concerns about the quality of this energy. The aim of the graduation thesis was to study the impact of solar power plant on the power quality in selected distribution network. The latter is determined by both, solar power plant design and distribution network and differs from case to case. The most important factors that influence the power quality are: quality of inverter, transformer power and impendence of the network. To minimize the impact of solar power plant on the distribution network, certain standards for inverter must be followed and current, voltage and frequency of solar power plant must be consistent with distribution network parameters. For power quality measuring, standard SIST EN 50160 was introduced. In our study, voltage quality was measured in agreement with latter standard before and after of connecting the solar power plant to the network. Our results show that solar power plant in studied network did not change power quality. We detected an increase in fifth and seventh harmonic component in current at the inverter exit, but its impact on the distribution network was not significant.