Abstract

Cross-country pipelines at times suffer unexpected leaks to the surrounding environment. The challenge faced by pipeline operators is to ensure that the field data is communicated to the Leak Detection System as quickly as possible to ensure a leak is caught and located. The communications system comprises sensors, RTUs, SCADA system and the supporting communication protocols, hardware, firmware and software systems deployed. All must work together to complete the cyclic information exchange for any data collected at sensors located along the pipeline to the Leak Detection System deployed in the control room. Data collection rates are typically in the range of about 5 to 15 seconds. Consequently, as “Real-time Transient Modelling” (RTTM) Leak detection systems needs time to build up evidence for and confirm the existence of a leak, it can take approximately 10–15 minutes to issue an alarm. By the time, corrective steps taken for “Abnormal Operational Condition” (AOC) occurs after the leak, an enormous quantity of product could have been lost from the pipeline, leading to safety and environmental concerns.

To address the “time to detect” issue an operator can turn to Negative Pressure Wave (NPW) technologies to provide a solution. However, the efficacy and location accuracy of such systems depends on the data sample frequency — with sample rates in the order of 10–100msec being preferred. Typically, NPW systems are deployed at the RTU, so that the required sample data rates can be achieved, which can make installation and maintenance difficult and expensive. Although sending all the sensor data to a centralised server for processing is possible, the collating, marshalling and sequencing of the data at the sample rates required for leak location accuracy makes this approach unappealing.

This paper presents a use case deployment of more advanced Ethernet protocol, the so-called Real-time Ethernet Deterministic Protocols, to reduce the data acquisition time. This is possibly the first time in the pipeline industry that data acquisition rates in the order of 10msec is achieved specifically for improvement of NPW leak detection performance.

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