The NPW method is based on the analysis of pressure signals. When a leak occurs, it causes a negative pressure wave propagating in both directions, upstream and downstream of a leak’s location. The wave induces pressure drops at measurement points. These events, including time series before and after an event, are recorded and pre-processed by RTUs or special processing units before being transmitted to the PSIpipelines LDS for analysis of data and wave front propagation.
The direct link between NPW and RTTM allows the use of the following hydraulic profile data in order to achieve accurate results: Density, temperature, pressure, pipeline diameter, pipeline wall thickness, sediments / waxing, batch interface
NPW takes the pipeline inventory into account. This is particularly important in case of batch operations. When systems do not consider pipeline inventory this inevitably leads to significant leak location errors.