Gas distribution: from networks' integrity management to new smart meters' performances technical evaluation

Safety represents the main goal for Natural Gas (NG) Distribution System Operators (DSOs) that have to operate very complex networks to supply gas to customers. However, the identification of the optimum strategy to manage NG distribution is a very challenging task for decision makers because of the size of the networks. Therefore, priorities have to be identified and many data about the operative conditions of the networks are required. While for the first topic a standardized and internationally accepted procedure has to be identified, for the second one the new NG metering philosophy, i.e. the Smart Metering gas, seems to be appropriate for the scope even if some technical issues have still to be solved. Consequently, the thesis is divided in two main parts. In the first one, attention is given to the distribution networks and to the proposal of a risk management approach to improve maintenance procedures. Thus, after a brief overview of the sector, existing safety performances of NG distribution sector are analysed. Furthermore, failure causes and consequences are investigated in order to propose a risk assessment approach in NG distribution. A case study is finally examined identifying several positive outcomes respect to the state of the art. In the second part of the thesis the NG smart metering is analysed with particular attention to the power supply that is one of the technical issues to be overcome for the success of the technology: in fact, because of the use of electrical batteries in smart meters, a limited capacity is now available. Consequently, the estimation of battery supply’s operative life is considered an important information for the success of the technology. For this reason, an experimental approach has been proposed and performed to estimate battery’s operative life.