Absolute maximum slope difference method for NPW real-time localization of leakage in pipelines

Pipelines provide an economical mode of transportation for hauling gas and liquids such as oil over long distances. Pipeline explosions cause massive loss of lives, and adversely impact both the environment and the economy. Accurate and automated detection of the arrival times of negative pressure waves (NPW) because of leakages is the key parameter in many pipeline leakage detection approaches. The method introduced here uses the absolute maximum difference in the slopes of NPW time-domain signals for accurate determination of the time of signal arrivals at the sensors. The proposed method involves Fiber Bragg Grating (FBG) sensor-based detection of the leakages, and determination of the arrival of NPW signals for accurate detection of the knee-points in the signals. The main advantage in using the proposed approach is determination of exact arrival time of NPW for accurate detection of leakage point locations along the lengths of pipelines. The experimental program includes construction of two separate gas and liquid pipelines for evaluation of the absolute maximum slope difference (AMSD) method. The study includes evaluation of the differences between the proposed method and conventional visual determination of the NPW arrival times, and the actual locations of the leakage sources in the experiments. The numerical approach introduced herein enables direct integration of the proposed method, for automated real-time monitoring of pipeline leakage locations.