Pipeline Monitor (PLM)

The Pipeline Monitor (PLM) application performs leak detection by calculating the system balance based on a volumetric over/short calculation. The information used in the over/short calculation is derived from the GSVs (Gross Standard Volumes) measured by the Tanking application and the Metering application. PLM also takes into account the changes in current pipeline conditions represented by GSV changes in pipeline linepack.

Once per minute, the PLM application reads the associated devices that measure tank, meter, and linepack values. Using these values, the volumetric change is calculated and then rolled into 9 integration periods to determine system loss. Each integration period is compared to predefined limits so that when a violation of a limit occurs, the Controller is alerted through an alarm.

The PLM application also maintains total balances for the current and previous days, the past seven days, and the current and previous months. The previous-day balance is a summation of the volumetric variance within that contract day; the current-day balance is a running summation of the variance for the current contract day.