The design and implementation of a control system for a multifeed gas network

In order to increase the efficiency of the gas supply system and to exercise more effective energy management British Gas have been concerned with the development of active feedback control systems, where the control objective is to reduce the average operating pressure in the low pressure network. This however poses a number of interesting control problems: gas networks are large, several hundred pipes, thousands of demands (consumers) several major infeeds per network, so it is a truly multivariable, large-scale control problems; with so many demands, how many measurements should be used and where should the measurement points be sited? An important factor here is the cost and reliability of data links from remote sites to a central control station; each gas network is different, can a common design approach be adopted? and how feasible is it to model such systems for control system design purposes? The paper addresses each of these problems and gives an overview of the design, development and implementation of the control system for a network with 30 miles of pipework, modelled as 650 sections, 4 infeeds and 4000 consumers