Optimal Sensor Placement for Pressure Wave Detection for Leakage Localization in a District Heating Network

The occurrence of a large spontaneous leakage in a district heating network leads to a pressure wave through the entire network. For safe operation, it is necessary to determine the leakage location and to exclude the affected network part. For optimal evaluation of the pressure wave, pressure sensors must be placed in the network to provide high-quality data. Already installed sensors can be used, but improved transmission technology is needed. For practical application, as few sensors as possible should have to be equipped accordingly. This paper addresses the questions of how many sensors are needed and where they need to be placed for a given network. In a joint research project, a method was developed that allows the evaluation of the pressure wave even with noisy input data. The method used for pressure wave evaluation works in two stages. In the first stage, the pressure drop times are determined from the measurement data. In the second stage, these times are compared with test leakages, for which corresponding pressure drop times are calculated. The second stage provides the test leakage locations at which the leakage can probably be localized. For the placement evaluation, all possible leakages should be included and compared with all test leakages. This paper shows how the resulting large amount of data is consolidated to achieve a suitable metric for the quality of the placement. This procedure is used for the optimal positioning of the sensors and the network is currently equipped accordingly. From the calculations, results for different positioning and with different numbers of sensors are shown. Additionally, it is addressed that some positions in the network might be unsuitable due to unfavorable superposition of traversing waves and resulting difficulties to detect the pressure drop time points. Exemplarily simulation results and measurement data are shown.