Balance equations estimation with bad measurements detection in a water supply net

Abstract The development and the correct exploitation of a water supply net demands control increasingly dependent on flow measurements. The flow balance permits detection of flow measurement errors and evaluation of the performance of the net. If we detect an error in a flow balance, we do not know which measurement device is wrong, nor find what type of error exists. The reconciliation of the measured data is not easy. To solve this problem, we decompose it in the following parts: (1) Analysis of the system, according to the observability and redundancy of the water net: we should obtain the matrix of system incidence, H . (2) Assignment to the meters of measurement uncertainty: thus, we obtain the covariance matrix, R . (3) Estimate of water flows of the supply net, applying the maximum likelihood least-squares estimation to the set of flow measurements using H and R matrixes. (4) Comparison of the estimated values with the measured values. In this paper, the authors use a practical approach. We have selected a water supply net that illustrates well enough all the difficulties encountered in water flow measurements.