Analiza energijske učinkovitosti električnih pogonov v procesu hlajenja tehnološke vode

KOPRIVC, LUKA (author), Fišer, Rastko (mentor)

Električni pogonski sistemi (EPS) so že vrsto let nepogrešljiv člen v industriji. Sposobnost vodenja in prilagajanja bremenu nam omogoča večjo fleksibilnost in zanesljivost v sistemu in nenazadnje tudi bolj varčno porabo električne energije. S tega vidika je zelo pomemben izkoristek EPS, če lahko določamo delovne točke in iščemo optimalen izkoristek glede na trenutno konfiguracijo. Magistrsko delo obravnava metodo določanja dejanskega izkoristka EPS v industrijskem obratu. Cilj je bil, da z meritvijo pridobimo potrebne podatke za izračun izkoristka inštaliranega EPS med njegovim obratovanjem v sklopu industrijskega proizvodnega procesa. Na začetku so opisane posamezne komponente EPS, njihovo delovanje in sistemi, v katerih delujejo. Gre za centralno hlajenje tehnološke vode porabnikov ter hlajenje hladilnega agregata. V prvem se EPS prilagaja potrebam bremena in je vrtilna hitrost spremenljiva, v drugem pa je vrtilna hitrost konstantna. V nadaljevanju je opisana merilna metoda, po kateri je potekala meritev ključnih parametrov pogona s konstantno vrtilno hitrostjo in pogona s spremenljivo vrtilno hitrostjo. Na vhodu EPS smo s pomočjo analizatorja moči merili električne parametre, na izhodu pa z diferenčnim merilnikom tlaka in ultrazvočnim merilnikom pretoka hidravlične parametre. Merjenje je potekalo v industrijskem okolju, nemoteno glede na proizvodni proces. Med meritvijo smo bili omejeni tudi časovno, saj bi v primeru dolgotrajnih merjenj lahko prišlo do odstopanj v obratovanju proizvodnega procesa, kar bi neposredno vplivalo na točnost in uporabnost merilnih podatkov. Na podlagi pridobljenih podatkov in meritev smo analizirali dejanski izkoristek EPS na letnem nivoju in opisali delovne točke obratovalnih stanj za celotno obratovalno leto. V analizi merilnih rezultatov je razvidno obratovalno stanje delovnih točk EPS na letnem nivoju. Ugotovili smo, da je EPS P195.60 najbolj obremenjen v poletnem času, najmanj pa v zimskem. Izkoristki EPS so manjši od pričakovanih in nikoli ne presežejo 60 %. Prav tako smo ugotovili, da je omenjeni EPS predimenzioniran, saj najvišja vrednost toka na letni ravni predstavlja 57 % nazivne vrednosti. Na podlagi razvitega modela smo simulirali, kako bi se EPS P195.60 obnašal v drugačnih pogojih ter kako bi se to odražalo na končni porabi električne energije. To smo izvedli s spremembo vhodnih podatkov (Δp in Q) za 10 % in ugotovili, da se izkoristek EPS bistveno ne spremeni. V zaključku so podane ugotovitve in predlogi za nadgradnjo trenutnega modela pri obravnavi dejanskega izkoristka EPS.

• Language: Slovenian
• Keywords: električni pogonski sistem, izkoristek, analiza sistema, industrija, asinhronski motor, črpalka
• Work type: Master's thesis/paper
• Organization: FE - Faculty of Electrical Engineering
• Year: 2018
• PID: 20.500.12556/RUL-99479
• Publication date in RUL: 25.01.2018

Secondary language

• Language: English
• Title: Energy efficiency analysis of electrical drives in technological water cooling process

Abstract

Electrical drives (ED) have been an indispensable part of industry for many years. The ability to manage and adapt to the load enables greater flexibility and reliability in the system, and moreover, a more economical use of electrical energy. From this point of view, the efficiency of the ED is very important, if we can determine the operating points and look for optimal efficiency in relation to the current configuration. The master thesis deals with the method of determining the actual performance of ED in an industrial plant. The goal was to obtain necessary data for the calculation of efficiency of the installed ED during its operation, in the course of the industrial production process. At the beginning, the individual components of the ED are described, their operation and the systems in which they operate. It is central cooling of the technological water of consumers and cooling of the cooling unit. In the first, the ED adapts to the load requirements and the rotational speed is variable, while in the other the speed of rotation is constant. The systems are also shown schematically. In continuation it follows description of measuring method, according to which the measurements of the drive with constant speed and variable-speed drive are carried out. At the ED input, electrical parameters were measured using the power analyzer, while hydraulic parameters were measured at the output, using a differential pressure gauge and an ultrasonic flowmeter. Measurements were carried out in an industrial environment, not being interrupted by production process. We were also limited in time, as in the case of long lasting measurements, there could be critical breaks in the operation of the production process. On the basis of data and measurements obtained, we analyzed the actual ED efficiency of the annual level and described the operating points for the entire operating year. The analysis of the measured results shows the operating state of ED at the annual level. We found out that ED P195.60 is the most loaded in the summer, and the least in the winter. The efficiency of ED is lower than expected and never exceed 60 %. We also found out that this ED is oversized, since the highest value of the current at the annual level represents 57 % of the nominal value. Based on the developed model, we simulated how the ED P195.60 would behave in different conditions and how this would affect the final consumption of electrical energy. We did this by changing the input data (Δp and Q) by 10 % and found out that the efficiency of ED does not change significantly. Finally, conclusions and suggestions for upgrading the current model of ED are given.

• Keywords: electrical drives, efficiency, system analysis, industry, induction motor, pump