Transients in Distribution Networks: Field Tests and Demand Models

Computerized transient-flow models have been used with great success in the analysis of water-hammer events in topologically simple pipeline systems, and the performance of these models is well documented. This paper addresses the relatively unexplored area of transients in complex pipe networks. A new formulation permitting system demands to be represented as a distributed pipe flux is presented. This approach is compared with two conventional methods for modeling demands in pipe networks. The results of a field test conducted on August 29, 1990, by the City of Calgary Waterworks staff on one of the city's major transmission and distribution subsystems is presented. The results are compared with the behavior predicted by a network transient model. The computer model was generally in good agreement with the field test data, with all three demand models giving comparable results, particularly with respect to the initial downsurge and the first upsurge following the pump trip. However, the transient's long-term decay was poorly represented by all three demand models.