Assessing whether a pipeline's balancing requirements can be met is a key day-to-day business process for system operators within the Gas industry. It is essential to manage the system to minimize compressor usage, unnecessary interruption, efficiently use linepack and maximise the use of capacity of the system to ensure a safe and secure supply. This paper describes how Advantica developed an automated decision support tool (the Nomination Acceptance Process, NAP) to simulate whether the shippers' nominations can be supplied over the forthcoming 48 hrs using both the current and predicted load on the system. Where demands cannot be met the decision support tool carries out a number of iterative on-line predictive simulations and provides details of the necessary actions required to balance the system to the system operators (e.g. buy/sell or interrupt). The inputs required to successfully manage this process are described, including data sources such as SCADA, hourly nomination profile data from external databases and user inputs. The paper includes details of how SCADA alarms are used to keep the operator informed of progress, and how the system is designed with redundancy, allowing it to fail-over between multiple instances of this business critical application.
Premier Transmission Limited (PTL) was acquired from the 50/50 joint venture owners, BG Group plc and Keyspan Energy Development Corporation, on 18 March 2005 by Northern Ireland Energy Holdings Ltd (NIEH). PTL is the owner of the majority of the Scotland to Northern Ireland natural gas transmission pipeline (SNIP), which comprises:
Scotland - Approximately 90km 24" diameter high-pressure pipeline connected to the BGE (UK) South West Scotland pipeline at Twynholm.
Sub-sea - Approximately 40km of 24" diameter high pressure pipeline.
Northern Ireland - Approximately 3km 24" high-pressure pipeline; a pressure reduction/off-take station supplying Ballylumford Power Station and an interconnection with the Belfast Transmission system. Phoenix Gas owns the pipeline beyond Ballylumford.
In 2004 Bord Gais completed the new 115 km "North West" pipeline connecting the SNIP pipeline to the Coolkeeragh power station in Derry. This pipeline resulted in an increase in contracted delivery pressure, and in flow rates along the SNIP pipeline. This reduced the margins on the SNIP pipeline and increased the likelihood of need for interventions. In order to validate the proposed operation of the pipeline and to consistently maximize the throughput on the pipeline, Advantica delivered an automated predictive capacity-modelling tool. This allows PTL to identify in advance their systems capacity, and identify balancing actions that may need to be taken. The design and creation of the bespoke NAP application formed part of a larger implementation for PTL covering pipeline simulation and leak detection software.
