Design of Archimedes Spiral Antenna to Optimize for Partial Discharge Detection of Inverter Fed Motor Insulation

Abstract

The partial discharge (PD) in inverter-fed motors generated from high frequency and short rise time impulsive voltage are more complex than traditional sinusoidal voltage operated motors due to the noise initiated from fast switching power electronics devices. Available PD sensors and related technology for DC and sinusoidal voltage cannot be used at repetitive impulsive voltage conditions. This work aims to report the design of antenna with optimized geometry and satisfied parameters to detect PD for impulsive voltage. The antenna is verified and the influence of both impulse voltage parameters and test configuration on PD features are discussed. The envelope detection technique after the filter in the frequency domain was proposed to reduce the complexity and cost of PD test hardware under impulsive voltages with fast rise times. The frequency domain energy of PD from motor insulation under is mainly distributed in the range of 0.6-1.8 GHz. By increasing the amplitude and frequency of input impulsive voltage, the range of PD energy spectrum is enlarged to (1.5-1.8 GHz) and by decreasing input amplitude the PD signal strength decays abruptly. Moreover, the high-frequency distribution of PD energy attenuates more severely with the distance and the electromagnetic energy of PD decays nonlinearly with the increase of propagation distance. Therefore, under the premise of satisfying the safety test, selecting the test distance below 15 cm can ensure that the test results have a high signal-to-noise ratio and signal integrity. The experience reported in this study could provide suggestions for off-line PD measurements for inverter-fed motor insulation evaluations for manufacturers.

Charge vibration behaviour in polyimide under the pulse voltage with different rise and fall times

“…On the other hand, the power electronic devices generate the pulse voltage and current with steep rise time at the time of turn-on and turn-off [5]. The polyimide (PI) film is widely used for insulation in different kinds of HV power electronic equipments, such as the inverter-ted motor, power electronic transformer and HV insulated gate bipolar transistor (IGBT) [6,7]. Thus, the stability and electrical strength of PI under the pulsed voltage is important for the safe operation of such HV power electronic equipments.…”

Numerical and Experimental Investigations on Influence of Internal Defect Parameters on Partial Discharge Induced UHF Signals in Gas Insulated Switchgear

“…The peak-to-peak voltage 𝑉 𝑝𝑝 of PD induced UHF signals gathered by the CMA and commercial disc sensors for defects in SF6 gas filled GIS test cells indicated nearly two-fold increase in the induced voltage for the UHF CMA. The CMA has the largest fractional bandwidth when compared to the spiral [23,34,35], slot [21], disc [22], fractal [36] and patch type [37] UHF sensors reported for PD detection. A detailed design and performance comparison of the CMA with commercial and existing UHF PD sensors can be found in [25].…”

Comparative Analysis of Partial Discharge Detection Features Using a UHF Antenna and Conventional HFCT Sensor

“…16 (a), the designed antenna has detected a PD pulse signal whose amplitude is 81.6mV as indicated in red color waveform trace. Since we know the value of background noise level detected by the same antenna was 8.8mV, therefore we can estimate the signal-to-noise ratio (SNR) of the designed antenna to be equal to (81.6mV/8.8mV= 9.3), this estimation was also used in the literature [19] . This clearly justifies that the designed antenna has a high SNR and signal integrity to detect PD signals with high sensitivity when it is even positioned at a distance ≥ 100cm from the PD source.…”

“…Performance was analyzed based on the SNR of the UHF signals captured by each antenna. P. Wang et al, [19], have recently proposed an Archimedes spiral antenna for partial discharge detection of inverter-fed motor insulation. This UHF antenna (whose frequency range is from 0.5GHz to 2GHz) has shown its potential in detecting PD under repetitive impulsive voltages with short rise times and high frequency voltage.…”