Study of generator modes effects on electric power quality and air gap

Abstract

The study examines hydroelectric power generator characteristics, voltage quality, air gap and vibration, in different operational modes -no-load mode, 90, 45, 10 MW load, 90 MW load with −50 MVAr to 20 MVAr reactive power and synchronous compensator mode with 0 MW-20 MW active power and synchronous compensator mode with −10 MVAr to −60 MVAr reactive power.Developed framework for power quality and air gap measurements assessment of hydropower generator shows that correlation exists between voltage, air gap and vibration characteristics. Analysis and comparison of different operational modes are performed to identify, which modes are important during diagnostics of machine condition in hydroelectric generators.

Eccentricity Of Slow-Speed Salient-Pole Generator: Analysis Based On Air Gap Spectrum

“…In our previous study [13] it was stated that for eccentricity evaluation the spectrum analysis should be used. From the frequency response theory it is known that frequency-domain considerations are applicable even when the signals are not periodic.…”

“…(2013) [16] found that correlations between the air gap, magnetic and vibration measurements performed for hydrogenerators are extremely important for detection of magnetic imbalance. In our previous study [13] a relationship was also established for the air gap and electromagnetic force (EMF) values, but the numerical correlation has not yet been obtained. The EMF-related unevenness of air gap [17] is the subject for future research.…”

“…the maximum air gap variation and delta value, or the deviation from average in % [2,12]; 2. the air gap spectrum [2]; 3. the air gap for each pole and rotor shape [1]. In our previous study [13], such evaluation was performed based on the delta value defined by the standard (Appendix F in [2]). This is a convenient tool for the evaluation, since the acceptable and the critical limits are clearly defined.…”

“…This case study refers specifically to a slow-speed hydropower generator and its eccentricity on site, and to the applicability of spectrum analysis proposed previously [13] for mathematical and computer models of the generator under different loads. The objective of this work was to present experimental results of air gap measurements for a hydropower generator and to evaluate its condition by different methods available to date.…”