Deregulation and power IT – the competitive edge22 February 1998
The radical changes wrought in the UK electricity industry over recent years come to a head this year. What began in 1991 with the break-up of the CEGB into separate, publicly-owned generation, transmission and distribution companies culminates in full competition in the UK market. With deregulation, a majority of business customers now choose to deal with independent traders or RECs supplying outside their geographical area. By 2000, all customers will be able to choose their meter operator. Syseca shows how generating stations can enhance their responsiveness, uptime and profitability by unifying control and monitoring functions under a common application layeer.
It is no surprise that with the massive changes in the distribution business brought about by deregulation, the IT focus has been on implementing best practice in customer-facing areas of business, as demanded by the market and the regulator. This means managing customer satisfaction by driving down interruptions, maintaining quality of supply, and efficiently handling customer queries.
But deregulation also creates an IT challenge for the generator. Power stations have moved from components in a vertically integrated, centralized, government owned organization into the major business assets of decentralized, competing, commercial entities. In the UK, the creation of three commercial thermal generation and energy trading companies, the opening of the market to independents, and the shift in fuel from coal to gas, has introduced competition which focuses on cost, integrity and timeliness of supply.
This level of competition means generating companies need to make greater demands on the real-time systems which control processes in the power station, and indeed has been the catalyst for the refurbishment and radical overhaul of many power stations. But overhauling the station itself is just one aspect. To make optimum use of their assets, generators need to extract more business information from raw data, to optimise through-life production against supply contracts and the spot market prices.
Proactive management, based upon this information, will yield competitive advantage through better service level management, enhanced plant information and business performance. But how do station operators ensure that they have the visibility of plant and process functions that they need? And how do they relate it to higher-level business systems?
The key issue is integration of systems station-wide. But true integration presents a real challenge to the generator; in fact, even interfacing data from the range of systems within the station can be difficult. Many stations have been operating for decades, with a mix of plant control systems which may not be easily integrated to provide the real-time data needed for maximum visibility. Such work may involve a great deal of labour-intensive software reconfiguration, interfacing work and follow-up maintenance. Furthermore, the data which forms the overall picture resides in multiple systems within the station, including DCS, legacy SCADA, PLC, incident and asset management systems, presenting a major obstacle to integration.
A further problem with existing plant and the mix of systems is the tremendous complexity of controls and machinery involved. Thousands of measurement points across the plant will provide the process control system with information on the changing conditions that apply at every stage of electricity generation. Performance details of machinery such as induced draught and forced draught fans, pulverising mills, burners and pumps, as well as boiler temperature and pressure readings have to be clearly displayed to enable operators to keep their units running smoothly.
Responding to this vast supply of information, an operator on a traditional control desk adjusts the plant or brings in standby plant by pressing switches or turning knobs. However, in order to co-ordinate resources, operators have to assimilate and react to the mass of data accruing from a variety of independent control systems and databases, taken from a huge range of dials and gauges. This lack of easy visibility creates inefficiency, and can inhibit a consistently fast response. Integration must therefore supply complete visibility of the generating process to the operators, giving them constantly updated, easily assimilated data on every resource in the plant.
Integration, not obsolescence
A total replacement of existing plant and control systems can be prohibitively expensive – both from actual implementation and from the lost revenue that would inevitably result from extended plant shut-down. Frequently the business justification is difficult to make in the fast-changing electricity market.
The alternative solution is to place a uniform control and visibility layer over all existing systems, placing a supervisory function which unifies the diverse control systems in a typical station to form a seamless operator interface, an integrated control system and a managed engineering interface. Ideally, the unified system would be able to integrate any future systems and act as a platform for the installation of strategic packages. It would also be managed by a 'soft' control desk – one in which all actions would be driven through computer screens – to enable flexible, responsive operation and easy management of tasks such as alarm handling, plant-automated control and automatic sequencing for start-up and shut-down.
Making the solution
So how can this level of integration be achieved? The best method is to use a single database which is able to handle the range of real-time data from the various systems in the generating station. Off-the-shelf products are available for this type of function, such as the well-established Hewlett-Packard Real Time Application Platform (RTAP) tool kit – running on Digital Alpha platforms. This single, hierarchical database can hold data from all plant, forming a picture of the processes in the station, and operates at speeds fast enough to monitor and control production processes in real time, while giving open access to other systems. Because the database is open, it also provides the conduit between plant and higher-level management systems.
This was the approach taken by Syseca in developing the Advanced Plant Management System (APMS) product in conjunction with National Power plc, which is now in place at five of their major UK power stations. APMS provides an industry-specific shell around RTAP and is able to hold all plant, derived and business data in a single hierarchical real-time database representing all coal plant.
It is able to recover long-term historic process data from an archive database, while holding recent process data in its own history tables.
Vertical integration of plant
The strategy driving the introduction of APMS was to close fully any functional gap that existed between business management, driven by external commercial factors, and the real-time management of power station plant. APMS achieves this vertical integration through the ability to correlate instructions (based on its own operational data) from the business side of the operation with plant data, and effect control accordingly to maximize efficiency. The integration of the plant-wide database provided by APMS and existing control systems facilitates further development.
Obviously, a key issue with integrating plant station-wide is the ability to interface with a wide range of external systems. Building upon the openness of RTAP, APMS interfaces with legacy systems such as CUTLASS and SWEPSPEED and modernises packages such as RTP 2000, OSI Software and corporate IT infrastructure. So that these systems can be configured and managed under the APMS database, Syseca utilise the ORACLE relational databases to link data variables across the various control and business systems.
In terms of plant monitoring and control, Unit operators interact with APMS through workstations. Typically a set of large back projectors enable the display of key overview graphics which can be seen clearly at a distance by a number of people.
APMS has already met with approval from plant operators. Drax power station in Yorkshire is National Power's largest and most modern coal-fired plant. Although designed for base-load operation, it faces a future where two-shifting and frequency regulation will become increasingly important features of a more flexible operating regime. The benefits that operators at Drax have perceived since the implementation of full APMS include:a better level of automatic control in the start-up and shut-down of a unit and an improvement in the fine control which can be exercised by the operator standardization in the way all operators control a unit in order to save energy costs, maximize start-up and shut-down efficiency and minimize possible future plant damage an instant view of the state of the unit at any time through clear schematic and overview diagrams; – provision of more relevant information to enable instant diagnosis to be made automatic control in an emergency shut-down situation such as results from an LP heater trip, which before APMS required the attention of four staff time saved in the control of plant frees the operator to manage important issues simplicity of communication with the system and the ability to change procedures quickly and easily improved control of plant helps minimize environmental emissions the ability to integrate existing systems, of which operators have experience and trust, together with the capability to add new systems in the future.
According to George Ecclestone, technical support engineer at the Drax coal fired power station: "The APMS installation is the cornerstone for the future operation of our units. It has enabled us to minimize our energy use during plant start-up and shut-down procedures, as well as minimizing plant damage by the use of advanced plant control techniques. The project has also delivered many fringe benefits beyond its original expectations."
The success of this cost-effective, integrated process management solution has led to a licensing agreement between National Power and Syseca to market the system world-wide. In the UK electricity generating companies Eastern Power and PowerGen are adopting and process control developers both in the UK and overseas are taking an interest in the APMS approach.
|Ultimate APMS at Drax|
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