Pioneering the future of power testing and monitoring
PD monitoring is generally present in all stator windings on the rotating machines and is one of the common failure problems. There is no red line on the actual limit of a new machine that was set by IEC (standard says this should be decided between the end user and manufacturer) however rule of the thumb is – if PD doubles in 6 months is a clear sign that the machine is failing.
Measuring PD offline has no big significance on Generators (no mechanical forces which tend to move the components and no thermal expansion).
Vibrations monitoring has been used for decades as proven tool for early detection of mechanical problems. Some of the electrical problems also reflect in vibrations due to imbalanced magnetic field which affects the spinning and causes vibrations.
The system monitors relative vibrations (which are displayed as actual movement in each XY direction, absolute vibrations (which are represented as vibrations in all directions) and monitors axial vibrations (for axial movements). High end piezo electric and proximity sensors are part of this system controlled by National instruments Controller and Award winning software with many diagnostic tools which help in identification the root cause problem.
End windings vibrations
Air gap monitoring
Precise air gap monitoring helps in evaluating and understanding the thermal expansion , parts looseness and eccentricity in generators due to the following reasons. Generator stator windings tend to deform due to material imperfection , magnetic field, stress , temperature problems, loose wedges and pour maintenance. Rotor bars and poles also tend to deform and loose due to material imperfection, forces and temperature problems. Air gap monitoring helps trend each pole clearance distance to permanent sensors (4 per unit) which are mounted at 90 deg. Each clearance is measured and the software algorithm addresses: eccentricity issues.
Shaft current monitoring
Rotor flux monitoring
Motors online monitoring is most widely accepted as the best practice for predictive maintenance of electrical motors. Rotor flux monitoring system for synchronous motors monitors each pole magnetic flux as the pole passes the permanently installed flux probe and compares signals obtained from each pole for early detection of rotor windings shorted turns and ground faults.
H2 leakage current in turbo generators monitoring