Design and Implementation of A State of the Art SCADA System.
This paper describes the design and implementation of a state of the art SCADA system for the gas production and transmission facilities of the Bahrain National Oil Company. It replaced a previous obsolete system. Primary considerations in the design of the new system included maximal independence from vendor configuration services for on-line addition of and modifications to production and transmission facilities, user friendly man machine interfaces using advanced workstation concepts, a highly responsive system using high speed communication links with remote terminal units and the use of a variety of media including dedicated cable lines, UHF radio and PSTN communications, all of the above to be obtained in a cost effective manner.
BANOCO has oil and gas production facilities that supply natural gas to the State of Bahrain for power generation, as feed stock to island industries and for domestic use. Major customers include Aluminum Bahrain, The Bahrain Petroleum Company Refinery, The Bahrain National Gas Company, the thermal power stations located at Sitra, Riffa and Juffair, and other smaller customers. Gas is also injected for reservoir pressure maintenance and gas lift. The total gas production capability of the field is about 1 BSCFD.
A SCADA system that was installed in 1980 was nearing the end of its life cycle. In 1990, it was decided to replace the system with a state of the art system that would meet BANOCO's requirements through this decade and beyond. This paper focuses on the concepts used and the methodology adopted to ensure that the most cost effective system was put in place with the above objective in view.
A basic premise that was followed throughout this project was to place no restrictions or mind sets on the technology of the vendor or the requirements of users of the system in regard to what could be achieved within the primary constraints of budget and the (then) current state of the art. For example, the specification specifically stated that the vendor could propose functionally superior alternatives to the hardware and software functions that were identified in the tender specification, for purchaser's consideration.
In line with the above theme, the generic term Remote Processing Unit (RPU) is used in this paper, to describe any of RTU.s, PLC.s and other smart communicating devices. The term Host system is used for the central computer system that monitors and controls the field facilities.
First, the design concepts used in preparing the tender specifications are presented in detail with reference to each of several functional areas common to most SCADA systems and as applicable to both the Host system and the RPU.s. Next, the implementation methodology is presented in the context of standard procurement procedures applied for purchasing the tendered system, as opposed to in-house design/implementation. Next, system installation and commissioning is described and finally the conclusions and lessons learned from the project.
The underlying theme for the design was configurability, ie. to achieve the maximum on line user configurability to meet the changing requirements of a dynamic production and process environment, apart from the usual requirements of system reliability, use of standard off the shelf hardware and software products, local support, etc.
As an example, not only should it be possible to add a point at any of the remote sites with the system on line, but complete surface facilities (eg an entire Gas Dehydration Unit (GDU), the corresponding station/RPU, etc.), should be capable of being added, along with any additional workstations, printers, communication channels, etc., without shutting down the system and without any reference to the supplier for making such additions.