Partial Discharge and Shaft Monitoring Quiz

What is the main benefit of online Partial Discharge (PD) monitoring?

• Reduces power generation capacity

• Allows early detection without machine shutdown

• Increases insulation stress

• Reduces generator size

Which part of the generator is most commonly affected by Partial Discharge issues according to failure statistics?

• Rotor winding

• Stator winding

• Bearings

• Shaft

What is the typical dielectric strength of air inside a void where PD may occur?

• 300 kV/mm

• 30 kV/mm

• 3 kV/mm

• 0.3 kV/mm

What failure mode is associated with the formation of voids due to improper resin application during coil manufacturing?

• Endwinding contamination

• Loose windings

• Poor impregnation

• Inadequate spacing

In shaft monitoring, what condition may be indicated by very low grounding brush current?

• High shaft voltage

• Proper grounding

• Poor grounding

• Shaft rub

What monitoring module is used with the IRIS GuardII+ system to detect shaft voltage?

• PDA

• RFA

• SM

• CSA

What component in the Partial Discharge system helps in noise separation using time-of-arrival?

• Voltage brush

• Shunt resistor

• Double-ended installation with couplers

• Thermocouple

What symptom can result from poor brush contact with the shaft surface?

• Rotor imbalance

• Shaft and bearing pitting

• Shaft alignment

• Temperature rise

Which of the following is NOT a cause of high shaft voltage?

• Magnetized nearby parts

• Vibration of stator core

• Static excitation spikes

• Turbine steam

Which issue does the term "ladder effect" in slot discharge refer to?

• Voltage imbalance in the generator

• Magnetic field asymmetry

• Electrical slot discharge from loose windings

• Misalignment of shaft