The VariSim Leak Detection technology provides high accuracy, high capability leak detection on all single phase pipelines yet it is SSLs firm belief that it is much more preferable to prevent the leak occurring in the first place (the cause) rather than relying on their detection (the symptom). The causes of leaks can be many, but they can often be reduced by using the simulator based montoring functions. These functions analyse pipework that is subjected to continual over and under pressurisation and assist in calming system operation by identifying the source of transients and minimising their effects.
As a company, Simulation Software Limited has significant experience in the pipeline leak detection environment, and this has been fully exploited within VariSim to create some of the best leak (and theft) detection approaches for liquid and gas systems. Our systems expand the capabilities of the two principal software-based methodologies that analyse the physical reaction to a leak in the pipeline.
VariSim uses balancing techniques to detect seeping leaks over extended timeframes, while pressure monitoring techniques detect large leaks very quickly. It makes sense to combine these effects to ensure the full range of leak detection capability. Although the physical reaction to a leak will never change, the way that the physical reaction is interrogated can always be improved.
Pipelines rarely operate in a steady state. In order to attain the highest leak detection capability (highest accuracy and lowest false alarm rates), it is therefore necessary for the leak detection system to accommodate the effects of transient behaviour. If the instrumentation permits, SSL will always recommend the inclusion of a transient simulator model which can incorporate the effects of variable product properties, temperature effects and changing flow regimes if required.
Balance and Pressure Wave monitoring both provide a response that can be analysed to detect the presence of a leak. The simulator-based balance methods produce imbalance responses in addition to important divergences between measured and calculated values of pressure and flow at key locations on the pipeline or network.
The pressure wave method monitors the change in pressure at key locations on the pipeline and verifies the presence of a true leak by analysing the magnitude of the responses and the times at which the pressure changes occur.
The presence of responses indicates an unexpected disturbance in the pipeline or an inconsistency in the systems’ calculations. Advanced methodologies are employed by the leak detection process to detect the presence of a true leak without raising false leak alarms. The methodologies include traditional filter and threshold comparison methods, statistical analysis methods and more recently, the application of artificial intelligence processes that self learn the pipelines’ behaviour.