For the earliest detection of insulation breakdown, partial discharge provides another level of high accuracy electric motor analysis over and above that achieved by the standard surge test. The partial discharge test has become more important to evaluate insulation in electric motors within the last few years. This is especially true do to the large increase of Variable Frequency Drives for the motor control.
The Partial Discharge test is characterized by detecting micro-discharges in a partial part of the insulation at an early stage. The micro-discharges in one part of the insulation system will, in due course, lead to increasing damage at this point. After hours, days, weeks, months or years the insulation system is weakened due to persistent micro-discharges and a complete failure occurs
Partial discharge and applied voltage sampled by the oscilloscope is sent to the computer to complete data storage and further processing and analysis. Phase Resolved Partial Discharge Based on partial discharge measurement data during the whole lifetime of PI films, phase resolved PD pattern under. Partial Discharge (PD) – Stator. Partial Discharge (PD) – Stator testing of HV machines was developed to detect and analyse the Partial Discharge (PD) signals found in HV Generators and Motors. Failures are caused by a combination of electrical, thermal, environmental and mechanical stress factors. DISCHARGE OF.MORTGAGE OR CHARGE. MORTGAGE OR CHARGE. Mortgage/Charge/Deed Vol. CT / SSCT / SCT Vol Fol. MORTGAGEE OR CHARGEE. ID / Co regn no Name. Address (within Singapore for service of notice). MORTGAGOR OR CHARGOR. ID / Co regn no Name. Address (within Singapore for service of notice) (D) CONSIDERATION. Partial discharge (PD) occurs if dielectric strength within a certain region of the insulation of an electric device is locally exceeded, but the surrounding insulation is strong enough to prevent total breakdown. In order to understand the occur-rence of PD and the response of electrical network to the excitation by discharge.
The Partial Discharge serves for testing the insulation quality. The test is always performed in connection with a high-voltage AC test.
Slot discharge refers to the observation that partial discharges (PD) may occur on the surface of the bar (half-coil), either within the stator core slot, or just outside of the slot. Figures 1-2 show photos of bars experiencing slot discharge considered as fairly serious and corrective action would be considered necessary. There are three.
The picture shows a loose winding wire. The winding wire touches the lamination or is a small distance away from it. In a high-voltage test such a defect is only detected with either a very high test voltage (not always possible) or if the winding wire is actually damaged at this specific location By means of the Partial Discharge (Arc-Detection) this defect is detected. |
The picture shows a slot in which a part of the slot liner is missing. The winding wire touches the lamination or is a small distance away from it. In a high-voltage test such a defect is only detected with either a very high test voltage (not always possible) or if the winding wire is actually damaged at this specific location By means of the Partial Discharge (Arc-Detection) this defect is detected. |
This picture shows a slot in which the slot insulation is missing. The winding wire touches the lamination or is a small distance away from it. In a high-voltage test such a defect is only detected with either a very high test voltage (not always possible) or if the winding wire is actually damaged at this specific location By means of the Partial Discharge (Arc-Detection) this defect is detected. |
Highlights:
IEEE Transactions on Dielectrics and Electrical Insulation>2010>17>5>1428 - 1440
journal ISSN : | 1070-9878 |
DOI | 10.1109/TDEI.2010.5595544 |
statorsageingelectric generatorslife testingmachine insulationmachine testingpartial dischargessurface conductivityslot partial discharge activityaccelerated aging teststator barsair-cooled generatorsstator winding ground insulationphased resolved partial dischargesurface modificationsstator bar surface degradationSurface treatmentBarsInsulationAgingDegradationSurface dischargessemi-conductive coating, temperature, vibration, conductivitySlot partial discharges, generator, stator bars, insulation
statorsageingelectric generatorslife testingmachine insulationmachine testingpartial dischargessurface conductivityslot partial discharge activityaccelerated aging teststator barsair-cooled generatorsstator winding ground insulationphased resolved partial dischargesurface modificationsstator bar surface degradationSurface treatmentBarsInsulationAgingDegradationSurface dischargessemi-conductive coating, temperature, vibration, conductivitySlot partial discharges, generator, stator bars, insulation