POWER STATION THERMAL EQUIPMENT DIAGNOSTICS SECTION

Since early 1980s, Power Station Thermal Equipment Diagnostics Section has been involved in development and implementation rotating machinery diagnostics (mainly vibration-based) in utility power plants and CHP plants. Our activities have been focused primarily on steam turbines.

At present, we are involved mainly in diagnostics based on measurements performed at certain time intervals and utilizing portable and configurable measuring equipment (off-line mode). Such approach may be viewed compatible with current trends. On-line diagnostic systems are installed on the most important and largest units only, due to high costs involved. Many medium-size power generating units, which form the bulk of generating capacities in Poland and many other countries, are fitted with monitoring systems, which are important from the point of view of operational safety, but usually do not run diagnostic procedures. Small units, of which many still remain in operation (mainly in industrial and municipal CHP plants) are often fitted only with simple vibration measuring devices. In such cases, off-line measurements provide a convenient and cost-effective means of diagnostic supervision.

Since the very beginning, our approach has been based on vibration measurement and analysis in the broad frequency range. Consequently we can account not only for vibration components resulting entirely from rotation, but also for those generated by interaction between medium flow and fluid-flow system elements. This gives a unique possibility to trace and evaluate evolution of the fluid-flow system condition, which is of vital importance for turbine operation. According to various estimations, about 20 to 30 percent of total forced outage time is due to the fluid-flow system failures, which are usually costly and time-consuming to repair.

Our activities have followed the development of technical diagnostics as a whole: first fault identification and location (qualitative diagnostics), then quantitative condition assessment and finally prediction of condition evolution.

Recently we have developed techniques based on:

• so-called criterial vibration levels (basic and limit), which correspond to various stages of technical condition evolution and allow for quantitative assessment; these values are determined individually for each machine, measuring point and vibration frequency band;
• analysis of long-time vibration histories (trends) in the broad frequency range, employing theoretical models specially tuned to match the specific case of steam turbines (so-called evolutional symptoms).

Both these techniques are currently employed in our investigations, performed in power plants. And both are under continuous development.

Our offer includes:

• Investigations of dynamic behavior of rotating machines (turbines, generators, punps, fans etc.) and determination of vibration levels in the broad frequency range;
• Spectral analysis of vibrations in rotating machines, including harmonic (low-frequency) and blade (high-frequency) components, in order to determine machine technical condition and its evolution;
• Determination of criterial (basic and limit) vibration levels in the broad frequency range;
• Measurements of acoustic characteristics of rotating machines in power plants;
• Expert opinions and case studies concerning dynamic behavior deterioration;
• Training of plant staff in the field of rotating machinery diagnostics.

Our most important recent partners from the power industry have included Turow, Ostroteka, Kozienice and Dolna Odra power plants.

We have participated in several government-financed research projects in the field of technical diagnostics. Among them, 'Modeling and Diagnostics of Mechanical, Aerodynamic and Magnetic Interactions in Power Turbine-Generator Units', coordinated by the Polish Academy of Sciences, is noteworthy. This project, completed in 2005, involved almost 60 scientists and research workers from over a dozen scientific and research establishments.

Head of Section e-mail: tomasz.galka@ien.com.pl

Address: 02-981 Warszawa, ul. Augustówka 36
phone: +48 223451-431
fax: +48 226428379