VIBRATION ABSORPTION AND HEALTH MONITORING IN A HYDROELECTRIC POWER PLANT

In Sweden, it's common to have power plants along water courses. Today, Sweden has more than 1 800 hydroelectric power stations in various sizes. Together, they stand for approximately half of the Swedish electrical power capacity. Many of them are old and are being renovated and upgraded as time goes by, partly to prevent failure but foremost to increase efficiency and power output. However, when optimizing a water turbine application for high efficiency, it is not uncommon that disturbing vibrations can occur. This may happen even if maximum power is not withdrawn from the generator. Previous, such a case was under study, a hydroelectric power plant was renovated and for some operating conditions like "high power output," unacceptable vibrations were experienced. The root cause of the high vibration levels as such, was identified and a number of various solutions were proposed. Structural modification was too unprofitable or basically impractical and was thus not considered. Active control was implemented and did successfully attenuate the harmful vibrations down to acceptable levels. This paper presents a vast range of data and shows multiple measurements that have been performed. The method of monitoring and comparison between different operating modes of the power plant is presented.