Operator Training Systems (OTS) are traditionally used for training pipeline controllers in how to deal with normal and abnormal operating conditions, however OTS can serve to provide multiple uses in an Oil & Gas pipeline software environment. One of these is as a test platform for a Liquid Computational Pipeline Model Leak Detection System (CPM LDS).
This paper demonstrates such a use and outlines the benefits of providing a testing environment that takes into consideration normal operating conditions (NOC) as well as abnormal operating conditions (AOC) and their impact on LDS performance. LDS performance maps can then be generated for most anticipated pipeline conditions. Details of hydraulic modeling, control system emulation, and SCADA telemetry simulation will be discussed as well as their impact on the fidelity of the OTS response and subsequent accuracy of LDS predicted performance. Review of the level of abnormal operating conditions and their implementation on the OTS will also be outlined and the resulting OTS behavior. Lastly, the determination of expected LDS performance for a range of normal and abnormal operating conditions will be summarized.
The use of offline methods to establish performance metrics for leak detection systems has been common in the pipeline simulation industry. Regardless of the leak detection method, the necessity to define the anticipated performance and validation of the design of the system is important. Several papers have addressed this topic. A previous study has used historical SCADA data provided to the LDS and analyse the response of the LDS with the use of statistical methods to superimpose leak events (1). In the absence of real pipeline data, as in the case of greenfield projects, the LDS vendor is left to wait until such data is available to be able to create an initial performance map for the LDS. Conditions of the pipeline that are not normally encountered are also problematic as the historical data would not exist. This pertains to failure modes not normally encountered or combined effects of transients and failure modes. To address this, we propose to use the OTS as a leak detection test bed.
The use of the operator training environment as a test bed for defining LDS performance is based on the assumption that the training environment provides a reliable platform that will allow for realistic recreation of pipeline operating conditions. Based on Schneider Electric's SimSuite Pipeline™ modeling tool the test bed used to illustrate this has several components of the real pipeline operating environment. These are the duplication of the SCADA system and its functionality, the duplication of the field response in terms of PLC/RTU algorithm and device switch gear response, and lastly the modeling of the pipeline hydraulics. All these components integrated together serve as the test bed that will provide a high level of fidelity to the real pipeline response as seen by a LDS in the production environment. The Figure 1 shows the functional architecture of these components.