International turnkey power plant provider

01/01/2012

Technical investigation of power fluctuations

Technical investigation of power fluctuations for an International turnkey power plant provider

Lloyd’s Register ODS was contracted by a leading provider of turnkey power plant solutions, to investigate observed power fluctuations of two generator sets at a fossil fired power plant in South America. The power fluctuation levels were below the allowable limits but the operator nevertheless wanted to pursue an investigation to get further insight into the matter.

A comprehensive measurement program was set up to identify causes of the power fluctuations. A high-resolution and versatile measurement system developed by Lloyd’s Register ODS was used to record various signals including rotating speed, dynamic torque, main currents, governor input, and vibration levels among other things. Measurements were taken at various operating conditions including loading, full load, and during coast-down, clearly showing that the power fluctuations occurred at the half-order frequency of the drive motors.

The key benefit from the study was a better understanding of the important mechanisms relevant for the observed power fluctuations, in this case the mechanical-electrical interaction and the influence of the electrical grid stiffness. With this knowledge, appropriate mitigation measures can be taken if deemed necessary. Further, the information can be used early in the design process to make the design less sensitive to the diverse properties of electrical grids in the different locations where power plants may be installed in the future.