Thesis (MTech(Electrical Engineering))--Cape Peninsula University of Technology, 2011 / In a situation, where there is a shortage of power generation or the power stations are operating with a very low reserve margin, as is typically the current position in South Africa, there is a need to operate distribution network at the highest possible efficiency by utilising network power loss reduction techniques. Such techniques are especially important when contingencies occur as they tend to increase loss, reduce efficiencies and cause power supplies to such networks to increase. This increase can cause the network or multiples of such networks to be load shed as the power stations do not have the reserve margins to meet this increased demand. The ideal situation would thus be to minimise network loss and in so doing decrease the amount of power needed and possibly avoid load shedding. Thus, there is a need to study efficiency, network loss reduction under contingency conditions and this is the focus of the research. Most large urban distribution networks are operated as ring main networks. Ring networks are considered to have less power loss. However, a major component in a ring network can cause the loss to substantially increase; resulting in power shortage in the network. There is an urgency to eliminate high network loss. An efficiency plan was developed for a large ring network that reduces the loss so that its input power can be decreased. In this way, the available power existing due to the contingency can be more evenly spread, and the number of ring main networks to be load shed could be reduced.

This Master’s thesis deals with the problem of distribution electrical network with a focus on solving the steady operation of the electrical distribution network for E.ON Brno - Lisen. The calculation is made by using BIZON PAS Off-Line. The first part of thesis is specialized on the distribution of individual LV and MV networks.The second part of thesis is specialized on the general calculation of the steady operation distribution network and describe criteria for the design and evaluation of this network. In the practical part is calculate existing network in selected area in which is located 53 distribution transformers. In the final part is evaluate the status of existing network and perform design optimization and assessment of this network.

Aqueous droplets submerged in an oil-lipid mixture become enclosed by a lipid monolayer. The droplets can be connected to form robust networks of droplet interface bilayers (DIBs) with functions such as a biobattery and a light sensor. The discovery and characterization of an engineered nanopore with diode-like properties is enabling the construction of DIB networks capable of biochemical computing. Moreover, DIB networks might be used as model systems for the study of membrane-based biological phenomena. We develop and experimentally validate an electrical modeling approach for DIB networks. Electrical circuit simulations will be important in guiding the development of increasingly complex DIB networks. In cell membranes, the lipid compositions of the inner and outer leaflets differ. Therefore, a robust model system that enables single-channel electrical recording with asymmetric bilayers would be very useful. Towards this end, we incorporate lipid vesicles of different compositions into aqueous droplets and immerse them in an oil bath to form asymmetric DIBs (a-DIBs). Both α-helical and β-barrel membrane proteins insert readily into a-DIBs, and their activity can be measured by single-channel electrical recording. We show that the gating behavior of outer membrane protein G (OmpG) from Escherichia coli differs depending on the side of insertion in an asymmetric DIB with a positively charged leaflet opposing a negatively charged leaflet. The a-DIB system provides a general platform for studying the effects of bilayer leaflet composition on the behavior of ion channels and pores. Even with the small volumes (~100 nL) that can be used to form DIBs, the separation between two adjacent bilayers in a DIB network is typically still hundreds of microns. In contrast, dual-membrane spanning proteins require the bilayer separation to be much smaller; for example, the bilayer separation for gap junctions must be less than 5 nm. We designed a double bilayer system that consists of two monolayer-coated aqueous spheres brought into contact with each side of a water film submerged in an oil-lipid solution. The spheres could be brought close enough together such that they physically deflected without rupturing the double bilayer. Future work on quantifying the bilayer separation and studying dual-membrane spanning proteins with the double bilayer platform is planned.