Saudi Arabia is facing a major increase in the demand for power and is expected to invest approximately $24 billion by 2011. The country’s population versus power demand in 1976 was 7.7 million/0.9 GW, in 2006 it was 23.7 million/29.9 GW and in 2024 it is expected to be 50 million/70 GW. In 2006, Saudi Electric Company (SEC) had 70 plants with generation capacity of 31 GW. To meet such major increased demand, foreign investors are being invited to participate in constructing independent power plant (IPP) and independent power and water plants (IWPP) under build, own and operate (BOO) agreements.
Gas turbines are monitored with IPS Asset Management
The PP8 plant in Saudi Arabia’s Central Province is one of two major power stations that supply capital city Riyadh with electricity. The plant is currently rated at 1850 MW, which will rise to 2330 MW after this expansion. The plant is currently controlled by four independent distributed control systems (DCS), two from IPS using Foxboro I/A, and two from other vendors. These latter DCSs have been struggling with obsolescence issues.
As part of the PP8 phase III expansion project, SEC has approved the plant’s expansion with the addition of four new gas turbines to increase capacity by 480 MW. The company was looking for a DCS that has the capability to control and monitor the new gas turbines, the overall balance of plant (BOP), and to provide a seamless interface with the existing DCS systems.
Defining a DCS
A DCS is defined as a hardware/software system that has, as its primary function, the collection and analysis of feedback from a given set of functions, for the purpose of controlling these functions. Control may be implemented by monitoring and/or systematically modifying parameters or policies used in those functions, or by preparing control reports that initiate useful action with respect to significant deviations and expectations.
A DCS distributes major control functions, such as controllers, historians and display units (HMI) into different components. The key advantage of a DCS is that it divides control tasks among multiple distributed systems, so if any single part of a system crashes, the plant keeps operating. The DCS also brought the benefits of data networking to the industrial world, avoiding the need to hard wire each control point, adding flexibility and reducing the cost of making changes in the production processes.
There are some control vendors looking to distribute control closer to the instruments and valves, potentially eliminating a layer of more robust processors. Moving control closer to the valves and instruments may save on automation costs here and there, but even greater value can be achieved by extending the control domain beyond the plant floor.
More so than minimizing the role of the conventional DCS and moving it deeper into the plant, we see the need to make it more powerful and extend its functionality to the business, supply chain and even customer systems. This could not only reduce costs in areas such as material and energy, which have a far more significant bottom-line impact than the cost of the automation, it couldalso drive much more revenue into the business through closed-loop control of throughput, yield, equipment utilization and other strategic variables.
New generation of control systems
This new breed of control system is called an enterprise control system (ECS). Instead of a DCS, an ECS can include a conventional DCS, SCADA or other control technology, but it must also involve an architecture that enables full plant floor inter-operation; open communication access across the business enterprise; support for asset performance management (APM) tools that enable unified maintenance and operations management; and a unified engineering environment across all plant floor domains. We know that sustainable improvement in production value that drives real revenue and reduction of the far more significant costs, such as materials and energy, requires an extended definition of the control domain, one that could include the instruments and valves. More importantly, it must distribute control to enterprise financial, supply chain and even customer systems.
An ECS enables manufacturers to develop solutions that span manufacturing business enterprises without concern for constraints traditionally imposed by crossing the boundaries of the different classes of systems.
The following four characteristics define an ECS: full plant floor inter-operation; open communication access across the business enterprise; support for asset performance management (APM) tools which enable unified maintenance and operations management; and a unified engineering environment across all plant floor domains. Depending on the control needs driven by client business strategy, an ECS could include the following components:
- A control system, which could be a traditional DCS, PAS or even a PLC-driven system, if the requirements are simple enough
- Drivers for seamless integration of systems and sub-systems regardless of vendors
- A standards-based, engineering and applications development environment, that fosters reusability of components
- A standards-based historian that facilitates data capture and sharing across enterprise applications such SAP NetWeaver or Microsoft Sharepoint, enabling, for example, better visualization of the relationships between plant floor and financial data
- A standards-based HMI that supports cross-enterprise views.
Going from managing one’s business to controlling it can reduce maintenance, materials and energy costs, but it can also reveal millions of dollars worth of production value, improve safety, and environmental compliance.
Integration of controllers and software
One value of a standards-based architecture is that tactical decisions, such as whether to use PLCs, PACs and general purpose HMI/SCADA software, become secondary. The primary issue is to determine the integration needs of the business, determine what is already in place to meet those needs, and then, and only then, bring in any additional control technology you might need to accomplish those goals. Open architecture means that companies no longer need to define their business around the limitations of their technology ” they can implement technology around their business.
It is difficult to compare one control technology to another outside of the context of the business strategy. The primary difference is that conventional systems involving PLCs, PACs, industrial computers, etc., are just not robust, flexible or integrated enough to drive try business value.
Depending on strategy, moving some basic functions to field devices, including first level shutdown functions, might be effective, but the latest developments in plant design in the petrochemical and chemical plants show that integrated control requires robust process unit-related communication and high level of control and safety function, which cannot be supported by the device level.
Ten years ago a DCS was used to control plant floor processes and it did so with great precision. Although some companies were changing to open industry architectures at that point, many were still using proprietary control technology and a few were even using proprietary analogue technology.
Ten years from now the DCS will have evolved into an true ECS, which extends the precise control that manufacturers and utilities have for their production processes to the real-time control of all enterprise assets, including financial, supply chain, and transportation, as well as production assets.
But by then, the control technology itself will be fully commoditized and the value of a company’s automation investment will be the end user’s proprietary engineering and business rules that their ECS drives. The role of the controls vendor will have expanded not just from delivering and maintaining the technical infrastructure, but in working with clients to help them define their operations in ways that fully leverage the benefits that the automation system delivers.
The Foxboro solution
IPS’s solution for PP8 is a Foxboro I/A DCS, together with the Plant Performance Monitoring Solution and a Foxboro RTU SCD5200 that will interface with the load dispatch centre, based 400 km from the main plant. IPS is also to supply a Triconex system following a request from SEC for a valve shutdown safety system to be included in the project.
“PP8 operation, production and maintenance staff will have an open DCS system that handles the new functionality stipulated and be further reassured with life cycle support that guarantees no drop in spare part or technology support over time. Further, with IPS currently establishing its office in Riyadh itself, the local support by IPS qualified engineers is assured,” explained Nahidh Elshaer, Power Director, IPS in Saudi Arabia.
SEC chose to standardize on the Foxboro I/A to control the plant in its entirety. Foxboro I/A is widely recognised as being a “field proven” DCS. Foxboro I/A has open communication protocols that allow third-party systems to interface with the DCS and a high degree of fault tolerance achieved in this application through a sophisticated (1GBPS) MESH network.
The Foxboro I/A DCS will control the four new turbines under SEC’s PP8 phase III
Foxboro I/A was the first “open” DCS and has now been installed for over thirty years, during which time IPS have built up a wealth of experience in the power generation applications, particularly in the monitoring and control of gas turbines. This experience is in evidence in the design of the system that controls the PP8 phase III expansion project. The following key points were instrumental in SEC choosing IPS for this project.
- Foxboro I/A is the first DCS to provide a uniform control and operation environment where the two existing I/A systems at the plant can be operated from any existing console
- Due to the open nature of Foxboro I/A, the DCS is also able to seamlessly interface with two other existing third party DCSs and the turbine controllers, enabling the centralized monitoring and control of the BOP and turbines units
- A direct connection from the DCS to IPS’s own asset management and maintenance software, Avantis, allows the installed solution to automatically generate maintenance work orders based on asset conditions
- IPS could fully integrate Foxboro I/A and the two third-party DCSs under one common system. This could then be interfaced with the company’s ERP system through an InFusion upgrade. This level of integration provides real-time information at the ERP level, facilitating faster, more accurate business decisions and added value business applications integration.
The InFusion upgrade is a key component of the new system. InFusion is an enterprise control system that combines industry-leading capabilities from across IPS with advanced enterprise information and integration technologies from both Microsoft and SAP, that allows dramatic reductions in integration costs.
InFusion was launched by IPS approximately two years ago and is being used cost-effectively to integrate multiple DCS systems into a common platform, which in turn communicates directly with ERP systems, most commonly SAP.
In conjunction with a suite of new performance services, IPS’s InFusion is helping SEC in this case to more effectively align operations and maintenance departments with the business to optimize overall asset performance management.
By adopting the InFusion platform, SEC will be able to bridge the gap between their planning, scheduling and documentation systems/applications. Real-time data can be collected from plants throughout the country, via the SEC communication backbone, while maintaining security and the data integrity of the control systems.
A number of challenges faced IPS, such as the provision of uniform distributed operation and control, the functionality requested by plant personnel and the creation of a “solid” upgrade roadmap for the future. It was interesting to note that vendors of PLC-based integrated control systems (marketed as a DCS solution) could not meet the project specifications that emphasized the need for a field proven DCS with standard functionality.
Furthermore, those vendors, which already had a DCS installed within the plant, were unable to support their own obsolete systems. Finally, as delivery was required within eight months, IPS had the advantage of a strong local presence that could meet this demanding schedule.
This is the first time in Saudi Arabia that GE Frame 7E gas turbines are to be monitored and controlled by an IPS Foxboro I/A DCS. SEC is hoping for further successes in the future, too.
A new office in Riyadh has been planned to cover the IPS installed base in the region, including PP8. MEE
Nahidh Elshaer, Invensys Process Systems, Saudi Arabia