Η παρούσα διπλωματική πραγματεύεται την μελέτη της ηλεκτροδότησης ενός αντλιοστασίου, καθώς και του ιδιωτικού Υ/Σ που θα έχει ο καταναλωτής από το δίκτυο ΜΤ της ΔΕΗ. Στα πρώτα κεφάλαια γίνεται μια θεωρητική προσέγγιση του προβλήματος. Ειδικότερα, παρατίθενται οι τύποι παροχής των ιδιωτικών Υ/Σ, ενώ αναλύονται τα μέσα ζεύξης και προστασίας της ΜΤ. Στη συνέχεια παρουσιάζονται τα είδη γείωσης των ιδιωτικών Υ/Σ ΜΤ-ΧΤ καθώς και οι κατηγορίες καλωδίων για την ΧΤ και την ΜΤ και τρόποι εγκατάστασης τόσο των καλωδίων ΧΤ όσο και αυτών της ΜΤ. Ακολουθεί μια περιγραφή των Μ/Τ ισχύων που χρησιμοποιούνται για την ζεύξη με το δίκτυο ΜΤ και τα μέσα προστασίας των Μ/Σ . Ταυτόχρονα αναπτύσσονται τα μέσα ζεύξης - απόζευξης και προστασίας XT αλλά και ο τρόπος λειτουργίας τους με σκοπό την αντιμετώπιση των ρευμάτων βραχυκύκλωσης που ενδεχομένως εμφανίζονται σε μια ηλεκτρική εγκατάσταση. Τέλος περιγράφονται οι πίνακες ΜΤ και ΧΤ μέσα στους οποίους τοποθετούνται τα μέσα προστασίας και ζεύξης - απόζευξης ΜΤ και ΧΤ του Υ/Σ, ενώ παράλληλα επισημαίνεται η αναγκαιότητα και τα πλεονεκτήματα της αντιστάθμισης της άεργου ισχύος και οι τρόποι επίτευξής της. Γίνεται ακόμη ιδιαίτερη αναφορά στην συντήρηση ενός Υ/Σ και στην αναγκαιότητα της. Στο 11ο κεφάλαιο έχουμε την μελέτη ενός αντλιοστασίου και ένα ένα τα βήματα που ακολουθούμε για την ολοκλήρωση της μελέτης από την επιλογή των κινητήρων , την διατομή των καλωδίων ΜΤ και ΧΤ , τις προστασίες τόσο στην ΜΤ και την ΧΤ όσο και στους κινητήρες , την επιλογή του Μ/Σ έως τον υπολογισμό των ζυγών ,τους πίνακες ΜΤ και ΧΤ και την αντιστάθμιση της άεργου ισχύος. / This thesis deals with the study of power supplying of a pump-station, as well as of a private Substation that the consumer would have, from the Medium Voltage network of DEH. In the early chapters is a theoretical approach to the problem. In particular, lists the types of provision of private M/L Voltage Substation, while analysing the connection and protection structures of MV. Then presents the types of groundings in private M/L Voltage Substations and also the categories of cables for LV and MV and ways of installation. Follows a description of power transformers used for coupling with the MV network and the protection of them. At the same time develop the means decoupling – coupling and protections at LV and their operation for dealing with potentially short-circuit currents appear in an electrical installation. Finally describes the MV and LV fields within are placed the protectιons of LV and MV coupling of the M/L Substation, while pointing out the necessity and advantages of counterbalancing the reactive power and ways of achieving it. Is a special reference to maintenance of M/L Substation and the need of it. In the 11th chapter we study a pump-station and one by one the steps to follow to complete the study from the choice of engines, the cross-section of cables LV and MV, protections both in MV, LV and engines, and the selection of suited power transformer till the calculations of bars, fields of LV and MV and counterbalancing the reactive power.

Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: There is a general lack of published research on sewage pump station problems and the removal of solids in South African sanitary sewers. Research was undertaken to investigate the problems at sewage pump stations by means of site visits, interviews, literature reviews and laboratory experiments. An in-depth literature study is presented on sewage pump stations, pump station problems and solids in sewers. The problems at sewage pump stations were categorised into identifiable groups with possible generalised solutions. The site visits and literature review indicated a specific lack of knowledge regarding screening baskets used to remove solids at sewage pumping stations. This led to the experimental testing of a screening basket on full scale in a controlled environment to develop an efficiency index for screening baskets. The efficiency index was determined using fuzzy logic methodology with predetermined solids load, basket height above the sump level and solids retention time. The fuzzy logic proved that the basket is best operated halfway submerged, after one hour retention time and with degradable solids in the system. The literature compiled and problems identified in this study were used as the backbone for the development of a conceptual Decision Support Tool (DST) for sewage pump stations. The DST is aimed at requiring limited inputs and providing maximum knowledge output and is presented as a software tool in MS Excel format. The functionality was added by applying visual basic applications in MS Excel user forms. The idea of developing a DST is to assist designers, sewage service providers and operators with understanding the various components and for problem identification pertaining to sewage pump stations in the future. The DST is relatively self-explanatory with a user friendly visual interface that is easy to operate. This study sets the scene for further research into efficiency indices pertaining to different components of sewage pump stations and their application in comprehensive sewage pump decision support tools. / AFRIKAANSE OPSOMMING: Daar is 'n algemene gebrek aan gepubliseerde navorsing oor probleme met rioolpompstasies en die verwydering van ongewenste voorwerpe in Suid-Afrikaanse sanitêre rioolsisteme. Navorsing is gedoen om die probleme by rioolpompstasies te ondersoek deur middel van terreinbesoeke, onderhoude, literatuurstudie en eksperimente in „n laboratorium. 'n Omvattende literatuurstudie is op rioolpompstasies, probleme by pompstasies en ongewenste voorwerpe in rioolnetwerke gedoen. Die probleme by rioolpompstasies is verdeel in identifiseerbare groepe met moontlike oplossings. Die terreinbesoeke en literatuuroorsig het 'n spesifieke gebrek aan kennis met betrekking tot skermmandjies, wat gebruik word om ongewenste voorwerpe by rioolpompstasies te verwyder, aangedui. Dit het gelei tot die eksperimentele toetsing van 'n skermmandjie deur die volskaalse opstelling in 'n beheerde omgewing om 'n doeltreffendheidsindeks vir skermmandjies in die praktyk te ontwikkel. Die doeltreffendheidsindeks is bepaal deur gebruik te maak van “fuzzy logic” metodologie met voorafbepaalde insette naamlik, die mandjie se hoogte bo die watervlak, soort ongewenste voorwerpe en die tyd wat die voorwerpe aan water blootgestel is. Die “fuzzy logic” bewys dat die mandjie die beste werking toon, halfpad onder die water, na „n een uur van blootstelling aan water en met degradeerbare voorwerpe in die stelsel. Die literatuur wat saamgestel is en probleme wat in hierdie studie geïdentifiseer is, is gebruik as die inhoud vir die konseptuele “Decision Support Program” (DST) vir rioolpompstasies. Die DST het ten doel om met beperkte insette die maksimum kennis te verskaf en word aangebied as 'n sagteware instrument in MS Excel formaat. Die funksionaliteit is bygevoeg deur die toepassing van die “visual basic applications” in MS Excel gebruikersvorms. Die doel van die ontwikkeling van 'n DST is om ontwerpers, riooldiensverskaffers en operateurs te help om die verskillende funksies en probleem-identifikasie met betrekking tot rioolpompstasies te begryp. Die DST is relatief selfverduidelikend met 'n gebruikers vriendelike visuele koppelvlak wat maklik is om te bedryf. Hierdie studie bied die basis vir verdere ondersoek na die doeltreffendheidsindekse met betrekking tot die verskillende komponente van rioolpompstasies en die toepassing daarvan in omvattende rioolpomp “DSTs”.

Transport of wastewater in sewer networks causes potential problems associated with gases which include ammonia, carbon dioxide, carbon monoxide, hydrogen sulfide and methane, in regard to odor nuisance, irritation, toxicity, and microbially induced corrosion. The extent of these problems depends on the emission rates of gases in the sewer atmosphere. To limit these kinds of problems an estimate of the gases emitted from the sewer network is to be known. In consideration to the above mentioned problems, a research has been taken up to estimate the two gases, namely, carbon dioxide and hydrogen sulfide from sewer wet wells. In this method, using Landtec GEM-2000 plus a multi-gas analyzer, the sample gases were collected from the wet well of pump stations for five days. Using the collected samples the emission rates of carbon dioxide and hydrogen sulfide are estimated.