Fire Safety at French CCGT Power Plant

Construction of the turnkey project, valued at €360 millions, was originally awarded to Siemens Power Generation Group (SPG) by Spanish power company, Endesa, which had acquired the French electricity generation and sales company, La SNET (Société Nationale d'Electricité et de Thermique) in 2004. La SNET was then sold to the German group E.ON in 2008.

The original thermal coal fired plant operating today was built over 60 years ago on the 1.87 square kilometre site at Saint Avoid, and named after the great French mining engineer. Situated approximately twenty kilometres west of the German border near Saarbrücken and halfway between Metz and Sarrebruk, it occupies a strategic position at the heart of the European electrical networks.

With a combined output of 1086 megawatts, the plant currently comprises three thermal tranches, which have been continually upgraded with the latest technology available, thus establishing the Emile Huchet plant’s reputation in the field of combustion of hard fuels and protection of the environment.

The two new combined cycle gas turbines (CCGTs) constructed alongside, were the first to be built by La SNET and are France’s largest combined cycle facility to date. Each has an output capacity of 430 megawatts, giving a combined total sufficient to supply as many as one million households, and together increased the installed capacity of La SNET by 30%. They utilise natural gas and feature high cost-efficiency, flexibility and environmental compatibility.

Working Together.

Siemens has been operating in France for over 150 years and built the Emile Huchet power station with specialist help from CMI (Cockerill Maintenance and Ingénierie) Energy, the manufacturer of waste-heat boilers. The Belgian boiler-maker has a long history of designing and installing boilers for electrical power plants and industry.

Siemens’s scope of supply encompassed the two gas turbines, two steam turbines and two generators as well as electrical systems and equipment, instrumentation and control systems and all mechanical equipment. Main civil works included building for the turbines and boilers, the cooling building, the administrative buildings and control rooms and all conducts and ancillary networks on site.

Supply Continuity.

Of vital importance and integral to Siemens’ turnkey project at Emile Huchet, were the safety and security systems. That is because supply-reliability is now identified as a critical issue, requiring considerable investment of effort and resources in the planning, design and implementation of systems by all parties involved.

The changes in world politics as well as those in megatrend demographics – that is urbanisation, the increasing and ageing population and climate change – all pose specific challenges to Energy Security. Concerns regarding the impact of traditional methods of energy production on the climate are prompting efforts to improve overall efficiency of power plants. Against a background of increased risk of terrorist attack on critical infrastructure, and where fires represent 50% of losses in fossil fuelled power plants, these efforts are driving safety and security standards higher in order to keep the plants operating at maximum productivity while making minimum impact on the environment.

The best way of ensuring supply continuity is to make power generation, transmission and distribution as efficient as possible and by safeguarding facilities with high-performance, risk management systems based on the very latest, proven technologies available. Integrated solutions cover equipment monitoring, fire detection, extinguishing, security, surveillance, access, intrusion, evacuation, energy, lighting, building management and comfort systems.

At Emile Huchet, Siemens helped address these challenges via a complete offering in the fields of fire safety, security and building automation. With field devices and integrated systems and solutions, the facility’s operators manage their risks better and respond to incidents more efficiently and effectively. Because, in doing so, they can optimise process efficiency, improve business continuity and safeguard supply reliability.

Fire Safety.

In any power plant, heavy power loads and defective equipment can quickly lead to overheating and/or short circuits. A fire could then typically occur following a long period of overheating and smouldering erupting into flames. On the Emile Huchet site, Sinteso S-line detectors are installed to provide the very earliest, essential “aspirating” detection of smoke. Through “advanced signal analysis” they offer detection accuracy and rapid notification through signal evaluation, even under the difficult detection conditions caused by frequent deceptive environmental phenomena such as dust, steam or welding fumes that occur on parts of the site.

There is also the potential for the site to upgrade to the video fire controller, which can be connected to the fire detection loop for visual verification of any alarm situation. In addition to a network of detectors and alarm sounders, there are hard-wired command points and manual extinguishing units for particularly vulnerable areas.

For extinguishing purposes, there are thirteen fire hydrants at strategic locations around the perimeter of the site connected to a 2,500-metre ring-main system and a large water tank with back-up connection to the existing water main. The tank holds 750 cubic meters of water reserves – sufficient to meet the demand of any outbreak by providing 120 minutes’ supply to the generators. The pump room houses a timed electric pump, a diesel pump (in case of large fire incidents) and a jockey pump to maintain a fixed pressure of 9 bar in the main ring system. There are fifteen indoor fire hydrants, again strategically located in various buildings around the site. All of the extinguishing measures were developed in consultation with the local fire service to ensure that, in the event of a fire, they have the optimum means to tackle it.

The main control room, the transformer station and other small transformer buildings are protected by fire detection and Siemens’ Sinorix gaseous “deluge” extinguishing systems. Sinorix extinguishes flames without harming people, assets or the environment, safely and reliably. It does so by utilising innovative technology such as CDT (constant discharge technology) or the combined gas/water Sinorix H2O. Constant discharge technology is based on using natural agents under controlled and constant gas discharge – that allows a reduction of overpressure flaps by up to 70% - to extinguish fire. Sinorix H2O Gas is an efficient extinguishing solution for protection of the power supply rooms through the combined advantageous use of nitrogen and water. Nitrogen displaces the oxygen and the water mist lowers the ambient temperature, resulting in reliable extinguishing and effective prevention of re-ignition. The system is individually tailored to bring the exact amount of water for the specific risk of fire.

Each main turbine building has its own dedicated XC10 fire extinguishing panel and the large open areas of the turbine hall are protected by a spray-deluge, sprinkler system, which is capable of delivering 4,000 litres of extinguishing agent a minute. The areas of the turbine building in which oil is used, such as the pump and motor stations, are covered by a system of foam/water mix. All cabling is carried out in anti-smoke pairs (“low smoke” and “fume”) and all cableways are also protected by detector and sprinkler systems.

Along with systems giving the earliest possible, reliable, error-free detection, alarm notification and the activation of pre-programmed control functions, fast and effective evacuation can be covered by the integrated solution. Pre-defined configurations of Siemens’ E100 voice system allows the appropriate announcements to be made in an evacuation scenario depending on the situation, the risk and pre-determined, phased evacuation schemes.

Full Integration.

There is also the potential to fully integrate the fire system with the site’s other electronic systems (security, energy and building management) via a central management system - Siemens’ M8000 Danger Management Station. This allows for the control room operators to monitor actual alarms, system faults, security breaches and equipment failures. It also creates an “early warning” system through the creation of fault detection diagnostics (FDD) based on historical data, to pinpoint potential problems with plant and equipment.

The plant went into production in early 2010 (after a rapid construction period of only 30 months) to help meet peak and intermediate load needs that have been increasing since full deregulation of the French market in 2007.

Contact: For further information, go to www.siemens.com/bt/utilities

(Author)

Horst Köhler is Head of Utilities Solutions at Siemens Building Technologies.