Slot Partial Discharge Average ratng: 3,5/5 1062 votes

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.

  1. Slot Partial Discharge Symptoms
  2. Slot Partial Discharge Definition

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

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.

Slot partial discharge definitionSlot Partial Discharge

Highlights:

  • determining the inception and extinction voltage according to IEC 61934
  • very high reproducibility owing to special filter technology
  • special coupling technology for measuring completely assembled motors
  • extremely free of any disturbances due to special high-frequent filter technology
  • no shielding of the test area necessary
  • partial discharge test up to 25KV
  • Verifies the quality of enameled copper wire (twisted pair), enamel-insulation, impregnation procedure
  • Can be performed with an HV-AC or at the surge test
  • Available on all MTC2, MTC3 and GLP3 testers

Source

IEEE Transactions on Dielectrics and Electrical Insulation>2010>17>5>1428 - 1440

Abstract

To improve our understanding of slot partial discharge (PD) mechanisms, an accelerated aging test was initiated two years ago. This long-term experiment is being performed on six stator bars subjected to slot PDs under electrical, thermal and mechanical stresses. It is well known that slot PD activity in air-cooled generators is harmful to the stator winding ground insulation. The degradation induced by slot PDs will modify the physical properties of the surfaces of the cavity where PDs take place and this in turn will influence the slot PD process. To understand the evolution of slot PD activity and the changes in its PRPD (Phased Resolved Partial Discharge) pattern, it is therefore essential to recognize and understand the interdependence between surface modifications and PD signals. This paper presents results of visual observations of stator bar surface degradation, changes in surface conductivity and the effect on the evolution of PD signals in the presence of slot PD activity under conditions of electrical, thermal and mechanical stresses.

Identifiers

journal ISSN : 1070-9878
DOI 10.1109/TDEI.2010.5595544

Authors

User assignment

Slot Partial Discharge Symptoms

Assignment remove confirmation

You're going to remove this assignment. Are you sure?

Lévesque, M.

  • Ecole de Technol. Super., Montréal, QC, Canada

David, E.

  • Ecole de Technol. Super., Montréal, QC, Canada

Slot Partial Discharge Definition

Hudon, C.

  • Inst. de Rech. d'Hydro-Quebec IREQ, Varennes, QC, Canada

Bélec, M.

  • Inst. de Rech. d'Hydro-Quebec IREQ, Varennes, QC, Canada

Keywords

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

Additional information

Publisher

Fields of science

Fields of science

    Share

    Export to bibliography