Induction Machine Insulation Health State Monitoring Based on Online Switching Transient Exploitation

Abstract

Today's variable-speed drives are usually operated close to their maximum tolerable conditions. The fast switching of modern power electronic devices leads to high stress of the winding insulation. As a result, an insulation breakdown may lead to sudden breakdown and high economic loss. To avoid unpredictable downtimes and enable repair on demand, monitoring of the insulation health state is getting more and more important. This paper proposes a method to monitor changes in the insulation health state by evaluating the machine high-frequency properties. The deterioration of the insulation condition is usually linked with a change of insulation capacity and thus also influences high-frequency properties. Initiating a voltage step excitation of the machine by the switching of the inverter, the high-frequency properties can be identified by measuring the resulting current response. This response is usually seen as current signal ringing and contains the machine high-frequency information. By applying signal processing tools, changes in the high-frequency information are extracted, and an insulation state indicator is derived. The applicability of the method is verified by measurements on two test machines (5.5 kW and 1.4 MW) having different power ratings as well as different insulation systems.

Online Condition Monitoring for Diagnosis and Prognosis of Insulation Degradation of Inverter-Fed Machines

“…A cheaper method was investigated in [13], [14] using a shunt resistor based current sensor. An alternate method was used in [15] to use the high frequency components of the common mode current to characterize a resonance model to track the change of capacitance over time.…”

Modern Diagnostics Techniques for Electrical Machines, Power Electronics, and Drives

“…In fact, 9 these events have been clearly the only international forums 10 fully dedicated to diagnostics techniques in power electrical 11 engineering. For this particular issue, it has been decided to 12 separate the different submissions into six parts: 13 • state of the art; 14 • general methods;…”

“…In [14], a method for monitoring the insulation health of 277 IMs is proposed. As the authors highlight, the objective of 278 this work is not to detect sudden insulation faults but to ob-279 serve a trend of the insulation state indicator over time.…”

Degradation Monitoring of Low-Voltage Electromagnetic Coil Insulation Based on Microscopic Image Analysis

“…Zoeller [12][13][14] proposed a method for stator insulation defect detection in traction drives machine windings by evaluating the current response after a voltage step excitation, which is based on the fact that parasitic winding capacitances changes as the insulation degrades. Nussbaumer et al [15] proposed a method to monitor changes in the insulation health state by evaluating the machine highfrequency properties. Jameson et al [16] proposed an SOV coil insulation health monitoring method based on the impedance spectrum, in which the accelerated degradation test of the SOV coil was performed and Spearman correlation coefficient was used to find frequency regions of interest within the impedance spectrum.…”