Abstract
On-line partial discharge (PD)measurement is now widely applied to motors rated 6 kV and above that are fed from the 50/60 Hz power system. However, many motors are being powered from invertors which facilitate variable speed motors to improve process efficiencies. One of the most common drives now being used is of the voltage source, pulse width modulation (VS-PWM) type. Such drives generate high voltage spikes in the kV range with risetimes in the submicrosecond range. These high voltage spikes are a form of severe electrical interference which render the detection of PD (with magnitudes 1000 x smaller) difficult, due to the overlapping frequency content in PD and the spikes. Thus PD detection on VS-PWM has been a challenge, in spite of the serious insulation aging that such drives may cause. This paper will outline the challenges in measuring the stator winding PD in motors fed by VS-PWM drives and describe a measurement system that is often effective. Results from measurements obtained using this system will be presented.
Highlights
The application of voltage source, pulse width modulated (VS-PWM) drives, on medium and high voltage motors (2.4 kV to 13.8 kV) is increasing
Just as for conventional power frequency motors, there is a desire for reliable on-line partial discharge (PD) detection methods for these medium and high voltage motors
This paper describes the technical challenges in implementing on-line PD
Summary
The application of voltage source, pulse width modulated (VS-PWM) drives, on medium and high voltage motors (2.4 kV to 13.8 kV) is increasing. Other drive topologies, such as load commutated and current source pulse width modulated schemes are available, due to cost considerations, VSPWM drives are becoming more common. These drives have resulted in stator winding insulation problems [1 - 7]. This observation is due to such inverters producing bipolar, short risetime voltage pulses with a high repetition rate. This paper describes the technical challenges in implementing on-line PD detection on motors fed by VS-PWM drives and provides some examples of application on operating IFD motors
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
