Vol.11, No 2, 2012 pp. 141 - 151
UDC
621.311.22:621.317.36
ANALYSIS OF THE CONDITION OF COAL GRINDING MILLS IN THERMAL POWER PLANTS BASED
ON THE T² MULTIVARIATE CONTROL CHART APPLIED
ON ACOUSTIC MEASUREMENTS
Emilija Kisić1, Vera Petrović1, Sanja Vujnović2, Željko Đurović2, Milan Ivezić1
1School of Electrical Engineering and Computer Science of Applied Studies, Belgrade, Serbia
2School of Electrical Engineering, University of Belgrade, Belgrade, Serbia
Abstract.
In modern thermal power plants coal grinding mills are an important and very frequent subsystem. As time passes the grinders in the mills become depleted and the functionality of these mills decreases. Because of that the mills need to be stopped periodically, every 1500 hours, so they can be checked and, if necessary, repaired. During this maintenance check the production of electricity decreases, which often results in a significant financial loss in case when this maintenance was unnecessary. In this paper we propose a new approach based on a measurement of acoustic signals in order to determine the time when it is necessary to stop the mills for repair. The goal is to increase the energy efficiency of the process by eliminating the need to unnecessarily stop the entire subsystem. The proposed procedure is based on an application of T2 multivariate control chart on extracted parameters of acoustic signals in frequency domain.
Key Words:
T ² control chart, spectrogram, coal grinding mills.
ISPITIVANJE STANJA MLINOVA U TERMOELEKTRANAMA NA OSNOVU T² MULTIVARIJABILNOG KONTROLNOG DIJAGRAMA PRIMENJENOG NA AKUSTIČKA MERENJA
U savremenim termoelektranama mlinovi za mlevenje uglja su važan i veoma čest podsistem. Tokom vremena, udarne ploče u mlinovima postaju istrošene i efikasnost ovih mlinova postaje sve manja. Stoga se mlinovi moraju zaustavljati periodično, svakih 1500 sati, kako bi se proverilo njihovo stanje i po potrebi izvršio remont. Tokom ove redovne provere stanja mlinova, proizvodnja električne energije opada, što veoma često dovodi do značajnih finansijskih gubitaka ukoliko remont nije bio neophodan. U ovom radu je predložena nova metoda bazirana na merenju akustičkih signala kako bi se odredio vremenski trenutak kada mlin treba da se zaustavi radi remonta. Cilj je povećanje energetske efikasnosti procesa izbegavanjem nepotrebnog zaustavljanja mlinova. Predložena metoda se zasniva na primeni T2 multivarijabilnog kontrolnog dijagrama na izdvojene parametre akustičkog signala u frekvencijskom domenu.
Ključne reči:
T² kontrolni dijagrami, spektrogram, mlinovi za mlevenje uglja
