Optimum Selection of Hydraulic Devices for Water Hammer Control in the Pipeline Systems Using Genetic Algorithm

Genetic algorithms have been used to solve many water distribution system optimization problems, but have generally been limited to steady state or quasi-steady state optimization. However, transient events within pipe system are inevitable and the effect of water hammer should not be overlooked. The purpose of this paper is to optimize the selection, sizing and placement of hydraulic devices in a pipeline system considering its transient response. A global optimal solution using genetic algorithm suggests optimal size, location and number of hydraulic devices to cope with water hammer. This study shows that the integration of a genetic algorithm code with a transient simulator can improve both the design and the response of a pipe network. This study also shows that the selection of optimum protection strategy is an integrated problem, involving consideration of loading condition, device and system characteristics, and protection strategy. Simpler transient control systems are often found to outperform more complex ones. INTRODUCTION Distribution networks are an essential part of all water supply systems. The construction and maintenance of these pipeline systems cost many millions of dollars every year. Traditionally, optimization processes have focused on steady (or nearly steady) state conditions. Even though this preoccupation in most water supply projects is understandable, transient phenomena are themselves unavoidable and often crucial to system performance and reliability. Despite their intrinsic importance, transient considerations have frequently been ignored or relegated to a secondary role when supply systems are designed or constructed. In order to protect a system from the impact of water hammer, various kinds of strategies are commonly suggested. Protection approaches range from installing specialized devices such as relief and reducing valves, air chambers and tanks to the selection of pipe properties and the modification of operational procedures. However, the selection, installation and operation of these hydraulic devices strongly depend on the specifics of the particular pipe system as well as on the experience/comfort of the designer/operator with the various approaches. Unfortunately, systematic exploration