Monitoring system for power plant
January 1st 2009

A remote condition monitoring system is helping a nuclear power plant monitor more than 90 electric motors,pumps and fans,providing early warning of impending failures and helping to keep plant availability high

Since its initial implementation in 2003, a FAG VibroCheck online condition monitoring system from FAG Industrial Services, the maintenance and condition monitoring company within the Schaeffler Group has on several occasions identified damage to bearings, imbalance in fans and unstable machinery at an early stage. This has enabled the maintenance team to order the necessary spare parts and resources and to plan the replacement of the damaged part within the regular maintenance schedule or shift.

FAG VibroCheck is suitable for condition monitoring of critical rotating machinery and components, such as gearboxes, bearings fans and pumps. Using selective frequency monitoring, it automatically detects imbalance and misalignment in rotating plant and machinery, as well as damage to individual bearings and gears.

Selective frequency monitoring enables the detection of even minor damage or defects at an early stage, since these will cause an increase in the amplitude of the characteristic frequencies.

FAG VibroCheck also uses demodulated signal analysis as this is well suited to shock pulses.

The system enables the monitoring of up to 2048 measuring points and can be integrated easily into a plant's existing systems. Remote monitoring is possible and alerts can be sent via email or SMS text message to the appropriate individual.

At E.ON Kernkraft, 226 separate measuring points are monitored by FAG VibroCheck, which provides maintenance with information on the condition of rolling bearings, gear sets, shafts and imbalanced rotors in fans and pumps.

Although 12 staff at E.ON are trained to use the system, the company also has a teleservice contract with F'IS, which includes the online remote monitoring of the plant and technical support by vibration monitoring specialists, who help to analyse and evaluate recorded data.

For example, the FAG VibroCheck system at E.ON Kernkraft recently detected bearing damage in a pump at an early stage. This damage was then confirmed by visual inspection and the bearing replaced in plenty of time by the maintenance team. If left undetected, the bearing damage would have led to failure of the pump, resulting in secondary damages of housing and shaft.

As a subsidiary of E.ON Energie, E.ON Kernkraft is a major contributor of electricity generation in Germany. The company operates six nuclear power stations in Bavaria, Lower Saxony and Schleswig-Holstein and is involved in a further five plants. The company employs around 2500 staff and generates a total annual output of 8,500kW, making the company one of the leading international generators of electricity.

E.ON Kernkraft's Grafenrheinfeld nuclear power plant in Germany was commissioned in 1981. The pressurised water reactor is rated at 1275MW and is cooled by two, 143m high, natural draught cooling towers.

The plant generates electricity for base load applications.

The working availability of the plant at this site has to be very high, at more than 90%, not only for safety reasons but for efficient maintenance of plant and machinery. Failure of individual components or machines can cause costly secondary damage or shutdown of the complete plant and therefore result in more 'lost' production.

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