Device for monitoring partial discharges in an electrical network

Patent metadata

Field	Value
Publication number	US-2016349309-A1
Application number	US-201615147249-A
Country	US
Kind code	A1
Filing date	May 5, 2016
Priority date	May 28, 2015
Publication date	Dec 1, 2016
Grant date	—

Abstract

A device for monitoring partial discharges in an AC electrical network, the monitoring device being mounted in a switching apparatus provided with a vacuum bottle connected to one phase of the AC network. The monitoring device includes a partial discharge detector positioned facing the vacuum bottle and an electronic processing unit receiving a first signal representative of the partial discharges detected by the capacitive sensor and receiving a second signal representative of the voltage of the electrical network. The processing unit includes discriminating means which are capable, according to the first signal and the second signal, of determining whether the partial discharges originate from a loss of vacuum in the vacuum bottle or originate from another cause external to the vacuum bottle.

First claim

1 . A device for monitoring partial discharges in an AC electrical network, the monitoring device being mounted in a switching apparatus provided with a vacuum bottle connected to one phase of the AC network, the monitoring device comprising:
a partial discharge detector positioned facing the vacuum bottle, an electronic processing unit receiving a first signal representative of the partial discharges detected by said detector, and receiving a second signal representative of a voltage of the AC electrical network,
wherein the processing unit comprises counting means for counting during a predetermined duration the pulses generated by the partial discharges on the first signal, and comprises discriminating means which are capable of calculating a phase angle of said pulses with respect to the second signal, and which are capable, according to a value of said phase angle, of determining whether the partial discharges originate from a loss of vacuum in the vacuum bottle.

2 . The monitoring device according to claim 1 , wherein the partial discharge detector is a capacitive sensor comprising a first conductive surface separated by an insulating layer from a second conductive surface connected to earth, the first conductive surface being positioned facing the vacuum bottle.

3 . The monitoring device according to claim 1 , wherein the discriminating means determine that the partial discharges originate from a loss of vacuum in the vacuum bottle when the phase angle is between −20° and +20°.

4 . The monitoring device according to claim 1 , wherein the discriminating means determine that the partial discharges originate from a corona effect when the phase angle is between 250° and 290°.

5 . The monitoring device according to claim 1 , wherein the discriminating means determine that the partial discharges occur between conductive parts at floating potential when the phase angle is between 170° and 210°.

6 . The monitoring device according to claim 1 , wherein the discriminating means determine that the partial discharges originate from a loss of vacuum in the vacuum bottle when the phase angle is between −30° and +30°.

7 . The monitoring device according to claim 1 , wherein the discriminating means determine that the partial discharges originate from a loss of vacuum in the vacuum bottle when the number of negative pulses is greater than the number of positive pulses generated by the partial discharges on the first signal.

8 . A switching apparatus comprising a vacuum bottle for each phase of a multiphase AC electrical network, wherein the switching device includes for each phase a monitoring device according to claim 1 .

9 . A method for monitoring partial discharges in an AC electrical network, the method being implemented in a monitoring device according to claim 1 .

10 . The method for monitoring partial discharges according to claim 9 , wherein the monitoring method determines that the partial discharges originate from a loss of vacuum in the vacuum bottle when the phase angle is between −20° and +20°.

11 . The method for monitoring partial discharges according to claim 9 , wherein the monitoring method determines that the partial discharges originate from a corona effect when the phase angle is between 250° and 290°.

12 . The method for monitoring partial discharges according to claim 9 , wherein the monitoring method determines that the partial discharges occur between conductive parts at floating potential when the phase angle is between 170° and 210°.

13 . The method for monitoring partial discharges according to claim 9 , wherein the monitoring method determines that the partial discharges originate from a loss of vacuum in the vacuum bottle when the phase angle is between −30° and +30°.

14 . The method for monitoring partial discharges according to claim 9 , wherein the monitoring method determines that the partial discharges originate from a loss of vacuum in the vacuum bottle when the number of negative pulses is greater than the number of positive pulses generated by the partial discharges on the first signal.

Assignees

• Schneider Electric Ind Sas

Inventors

• Schellekens Hans
• Preve Christophe

Classifications

• G01R31/3274

  Details related to measuring, e.g. sensing, displaying or computing; Measuring of variables related to the contact pieces, e.g. wear, position or resistance (measuring contact resistance G01R27/205) · CPC title

• G01R31/1254 Primary

  of gas-insulated power appliances or vacuum gaps (testing switches G01R31/327; detecting electrical or mechanical defects in encased switchgear H02B13/065) · CPC title

• H01H9/54

  Circuit arrangements not adapted to a particular application of the switching device and for which no provision exists elsewhere · CPC title

• H01H33/668 Primary

  Means for obtaining or monitoring the vacuum · CPC title

• G01R31/3275

  Fault detection or status indication · CPC title