Reliability analysis of distribution network

The knowledge of the reliability of distribution networks and systems is important consideration in the system planning and operations for development and improvements of power distribution systems. To achieve the target as minimum interruptions as possible to customers, utilities must strive to improve the reliability but at the same time reduce cost. It is a known fact that most of customer interruptions are caused by the failure in distribution system. However, valid data are not easy to collect and the reliability performance statistic not easy to obtain. There is always uncertainty associated with the distribution network reliability. For evaluation and analysis of reliability, it is necessary to have data on the number and range of the examined piece of equipment. It’s important to have database for failure rates, repair time and unavailability for each component in distribution network. These studies present the analysis of distribution networks and systems by using analytical methods in SESB’s distribution substations and network systems. These studies use analytical methods to determine the reliability indices and effect of distribution substation configuration and network to the reliability indices performance. Then the result obtained will be compare with the actual data from SESB to determine the area of improvement required for mutual benefit and also for improvement in the future studies

Can Negligible Cooperation Increase Network Reliability?

In network cooperation strategies, nodes work together with the aim of increasing transmission rates or reliability. This paper demonstrates that enabling cooperation between the transmitters of a two-user multiple access channel, via a cooperation facilitator that has access to both messages, always results in a network whose maximal- and average-error sum-capacities are the same---even when those capacities differ in the absence of cooperation and the information shared with the encoders is negligible. From this result, it follows that if a multiple access channel with no transmitter cooperation has different maximal- and average-error sum-capacities, then the maximal-error sum-capacity of the network consisting of this channel and a cooperation facilitator is not continuous with respect to the output edge capacities of the facilitator. This shows that there exist networks where sharing even a negligible number of bits per channel use with the encoders yields a non-negligible benefit.Comment: 27 pages, 3 figures. Submitted to the IEEE Transactions on Information Theor

Communication Networks with Endogenous Link Strength

This paper analyzes the formation of communication networks when players choose endogenously their investment on communication links. We consider two alternative de?nitions of network reliability ; product reliability, where the decay of information depends on the product of the strength of communication links, and min reliability where the speed of connection is a¤ected by the weakest communication link. When investments are separable, the architecture of the efficient network depends crucially on the shape of the transformation function linking investments to the quality of communication links. With increasing marginal returns to investment, the efficient network is a star ; with decreasing marginal returns, the con?ict between maximization of direct and indirect bene?ts prevents a complete characterization of efficient networks. However, with min reliability, the efficient network must be a tree. Furthermore, in the particular case of linear transformation functions, in an e¢ cient network, all links must have equal strength. When investments are perfect complements, the results change drastically : under product reliability, the efficient network must contain a cycle, and is in fact a circle for small societies. With min reliability, the e¢ cient network is either a circle or a line. As in classical models of network formation, e fficient networks may not be supported by private invesment decisions. We provide examples to show that the star may not be stable when the transformation functions is strictly convex. We also note that with perfect substitutes and perfect complements (when the e¢ cient network displays a very symmetric structure), the e¢ cient network can indeed be supported by private investments when the society is large.communication networks ; network reliability

Reliability of genetic networks is evolvable

Control of the living cell functions with remarkable reliability despite the stochastic nature of the underlying molecular networks -- a property presumably optimized by biological evolution. We here ask to what extent the property of a stochastic dynamical network to produce reliable dynamics is an evolvable trait. Using an evolutionary algorithm based on a deterministic selection criterion for the reliability of dynamical attractors, we evolve dynamical networks of noisy discrete threshold nodes. We find that, starting from any random network, reliability of the attractor landscape can often be achieved with only few small changes to the network structure. Further, the evolvability of networks towards reliable dynamics while retaining their function is investigated and a high success rate is found.Comment: 5 pages, 3 figure

Better safe than sorry? Reliability policy in network industries

This report develops a roadmap for reliability policy in network industries. Based on economic theory, we analyse the relationship between reliability and various types of government policy: privatisation, liberalisation, regulation, unbundling, and 'commitment policy'. We let government policy depend on (1) the feasibility of competition between networks, (2) contractibility of reliability, and (3) the relation between profit maximisation and public interests. We test this roadmap on the basis of the empirical literature and case studies on electricity, natural gas, drinking water, wastewater, and railways.

Condition monitoring and prognostic indicators for network reliability

Large-scale investment in transmission and distribution networks are planned over the next 10-15 years to meet future demand and changes in power generation. However, it is important that existing assets continue to operate reliably and their health maintained. A research project is considering the increased use of simulation models that could provide accurate prognostics, targeting maintenance and reduce in service failures. Such models could be further refined with parameters obtained from on-line measurements at the asset. It is also important to consider the future development of the research agenda for condition monitoring of power networks and with colleagues from National Grid, PPA Energy and the Universities of Manchester and Strathclyde, the research team are preparing a Position Paper on this subject