Drax Power - Common Services

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Business Challenges

Station services systems are the ancillary plant control systems, which control the plant that is common to all six generating units and includes such plant as the 275KV/400KV electrical switching plant, cooling water, water pre-treatment and demineralisation plants, boiler
fuel oil, air compressors and many more.  The project included the refurbishment and modernisation of the main control room, which gives Drax Power a completely computerised ‘soft desk’ based control room, allowing them to operate the power station safely, flexibly and efficiently from one central location.  Their ability to operate competitively in the power generation market is significantly enhanced by this
project.

Common plant items serve all six generating units so this work had to be carried out whilst the generating units were running and with minimum disruption.  Similarly, minimal disruption to the main control room during the project was essential to permit continued operation at the station.
The geographical dispersion of the plant at Drax also posed some challenges given that the site spans at least a mile across with some plant located in remote areas.

As a result it was a very demanding project to manage safely and consideration had to be given to system design and working procedures. All of this presented significant challenges for both Drax and Capula to overcome.  A detailed plan was jointly developed,
which included a carefully orchestrated programme of work involving temporary connections of equipment, mini plant item outages, reduced operation and extended working, which included working overnight and at weekends.

How We Helped

Capula designed and installed amodern station services process control system solution that met all of the needs of the new scheme.
The new system replaced existing legacy systems including digital control systems such as Cutlass, a number of disparate PLC systems, conventional electrical control and instrumentation equipment.

The entire system controls around 10,000 signals and comprises 4 APMS SCADA computers and 22 Schneider Electric PLC systems. Around 320 new plant instruments were also installed and the new systems interfaced to the relevant protection interlocking systems and existing plant equipment which was retained.  One of the key features of the architecture is the introduction of a site-wide fibre-optic
communications backbone. This involved significant civil works and provides a 100Mb self-healing fibre ring using switched Ethernet technologies.

Included in the project was the complete modernisation and automation of the Water Treatment Plant (WTP) which was a significant project in its own right. Across the plant Capula installed many new instruments tomeasure flows, pressures and levels etc. to increase the ability to monitor process parameters and enable increased automation and monitoring.

A key feature of the architecture are the interfaces between the station’s services systems, water treatment plant system and the existing six generating unit control systems. Key information, controls and alarms have to be presented to different operators, according to the operation rules defined by Drax, to enable the operation team to safely and efficiently operate the plant in all conditions.

The modernisation of the central control room involved removal of all existing control desks and replacement with a modern ‘soft desk’. A number of large LCD display screens were installed along with a number of workstations. These had all been carefully designed by Drax Power to ensure safe and ergonomic operation of the plant.