A Systematic Methodology to Assess Hydraulic Reliability and Gas Supply Reliability of the Natural Gas Pipeline Network

Reliability of the natural gas pipeline network is related to security of gas supply directly. According to the different required functions of the natural gas pipeline network, its reliability is divided into three aspects, namely mechanical reliability, hydraulic reliability, and gas supply reliability. However, most of the previous studies confused the definitions of the hydraulic reliability and gas supply reliability. Moreover, the uncertainty in the process of supplying natural gas to the targeted market and the hydraulic characteristic of the natural gas pipeline network are often ignored. Therefore, a methodology to assess hydraulic reliability and gas supply reliability of the natural gas pipeline network is developed in the study, and the uncertainty and hydraulic characteristic of the natural gas pipeline network are both considered. The methodology consists of four parts: establishment of the indicator system, calculation of the gas supply, prediction of the market demand, and assessment of the hydraulic reliability and gas supply reliability. Moreover, a case study is applied to confirm the feasibility of the methodology, and the reliability evaluation results provide a comprehensive picture about the abilities of the natural gas pipeline network to perform the specified gas supply function and satisfy consumers' demand, respectively. Furthermore, a comparison between these two types of reliability is presented. The results indicate that the natural gas pipeline network may not be able to meet the market demand even if the system completes the required gas supply tasks due to the impact of the market demand uncertainty.

Designing Water Distribution Network To Aledekhar and Alshababia and supporting it by new Pipes by using genetic algorithms technic

This research involves the redesigning (replacement) of the water disterbution network at Aledekhar and AlShababia , using genetic algorithm technology,then studying Add new Pipes to the current network with in parallel with the old, comparing the two solutions economically and hydraulically, and determining the coefficient of Hydraulic Reliability based on the study of the status of the network designed usingthetechnology of genetic algorithms by testing under the Fire situation, to achieve a more optimal solution, by Using software called Darwin Designer, this software was designed by the South African hydrologist Zheng WU in 2003. The results of the study showed that using genetic algorithm technology can achieve significant savings in water network projects of more than 23%, access a better hydraulic solutions and achieve hydraulic reliability of up to 100%.

Water Distribution Network Reliability: are Surrogate Measures Reliable?

Water distribution networks (WDNs) must be reliable infrastructures since they provide an essential service to society. Reliability assessment is a complex task and involves various aspects: mechanical, hydraulic, water quality, water safety, among others. This paper focuses on the hydraulic reliability. Hydraulic reliability is computationally hard to measure directly, therefore researchers came up with surrogate measures, like the resilience index, the modified resilience index, the flow entropy or the diameter-sensitive flow entropy, that are simple and fast to compute. But, are these surrogate measures reliable to be used in the design of WDNs?This paper proposes a new reliability index based on the surplus flow available on each node to mitigate the effects of a pipe failure. To illustrate the applicability of this new index, a WDN example is optimally designed using a simulated annealing algorithm. Results show that the solutions based on the flow entropy or on the proposed index are more reliable than the others, and, also, the maximization of the other reliability indexes gives only a residual contribution to the global reliability (or even no contribution at all).