PARTIAL DISCHARGE DETECTION APPARATUS AND DETECTION METHOD OF ELECTRICAL ROTATING MACHINE

• US 20070139056A1
• Filed: 02/20/2007
• Published: 06/21/2007
• Est. Priority Date: 08/20/2004
• Status: Abandoned Application

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Sekito, Shinobu, Sakai, Masahiro, Inoue, Yoshiyuki, KANEIWA, Hiroshi
• Application Number:
  US11/676,932
• Publication Number:
  US 20070139056A1
• Time in Patent Office: Days
• US Class Current: 324/536
• CPC Class Codes: G01R 31/1227 of components, parts or materials G01R31/1209, G01R31/1218, G01R31/18 take precedence; circuits therefor G01R31/14; testing vessels of electrodes G01R31/16
• CPC Class Codes: G01R 31/34 Testing dynamo-electric machines
• CPC Class Codes: G01R 31/346 Testing of armature or field windings

Abstract

A partial discharge detection apparatus of an electrical rotating machine includes a metal frame connected to a stator frame of the electrical rotating machine, a power line connected to one of a stator winding corresponding to one phase of three phases in the metal frame and a neutral point lead line connected to a neutral point of three-phase stator windings and arranged in the metal frame to propagate a partial discharge signal generated by degradation of the stator winding, a sensor including a rod antenna which is installed around the power line or neutral point lead line in the metal frame to electrostatically and magnetically induce the partial discharge signal propagated to the power line or neutral point lead line, and a detector which receives, via a signal lead line, a signal generated in the sensor and detects partial discharge by signal processing.

Claims

1. A partial discharge detection apparatus of an electrical rotating machine, comprising:

an electrical conductive element which is electrostatically coupled to a stator winding corresponding to one phase of three phases of an electrical rotating machine or a power line or a neutral point lead line connected to a neutral point of three-phase stator windings and is in non-contact with the power line or neutral point lead line;

an impedance converter which has an input terminal electrically connected to a terminal of the electrical conductive element and has an input impedance higher than an output impedance; and

signal processing means for processing a detection signal obtained from an output terminal of the impedance converter to detect a partial discharge pulse signal.

3. A partial discharge detection apparatus of an electrical rotating machine according to claim 1 or 2, wherein a transmission circuit is connected to the output terminal of the impedance converter so as to match the impedances, and the signal processing means receives a detection signal obtained from an output terminal of the transmission circuit.

6. A partial discharge detection apparatus of an electrical rotating machine according to claim 1 or 4, wherein the electrical conductive element and the impedance converter are supported by an insulating plate that is detachably attached to an inspection window provided in a hollow electrical conductive frame arranged around the power line or neutral point lead line.

8. A partial discharge detection apparatus of an electrical rotating machine according to claim 1 or 4, further comprising a coil magnetically coupled to the power line or neutral point lead line in correspondence with the electrical conductive element, and the signal processing means detects the partial discharge signal by discriminating a signal propagated from the electrical rotating machine from a signal propagated from outside the electrical rotating machine on the basis of whether a product of a polarity of an output signal peak from the impedance converter and a polarity of an output signal peak induced in the coil is positive or negative.

2. A partial discharge detection apparatus of an electrical rotating machine, comprising:

a capacitor having one terminal connected to a stator winding corresponding to a phase of three phases of the electrical rotating machine, a power line connected to the stator winding or a neutral point lead line;

an impedance converter which has an input terminal connected to the other terminal of the capacitor and has an input impedance higher than an output impedance; and

signal processing means for processing a detection signal obtained from an output terminal of the impedance converter to detect a partial discharge pulse signal.

7. A partial discharge detection apparatus of an electrical rotating machine according to claim 2 or 5, wherein the capacitor and the impedance converter are supported by an insulating plate that is detachably attached to an inspection window provided in a hollow electrical conductive frame arranged around the power line or neutral point lead line.

9. A partial discharge detection apparatus of an electrical rotating machine according to claim 2 or 5, further comprising a coil magnetically coupled to the power line or neutral point lead line in correspondence with the capacitor, and the signal processing means detects the partial discharge signal by discriminating a signal propagated from the electrical rotating machine from a signal propagated from outside the electrical rotating machine on the basis of whether a product of a polarity of an output signal peak from the impedance converter and a polarity of an output signal peak induced in the coil is positive or negative.

4. A partial discharge detection apparatus of an electrical rotating machine, comprising:

at least two electrical conductive elements having equal or different capacitances, the electrical conductive elements being electrostatically coupled to a stator winding corresponding to one phase of three phases of an electrical rotating machine or a power line or neutral point lead line connected to a neutral point of three-phase stator windings and being in non-contact with the power line or neutral point lead line;

at least two impedance converters having different input impedance values, each impedance converter having an input terminal electrically connected to the other terminal of a corresponding one of the electrical conductive elements and having an input impedance higher than an output impedance; and

signal processing means for receiving detection signals obtained from the impedance converters and determining, as a partial discharge signal, a pulse signal that is obtained from one of the impedance converters, which has a large input impedance value, simultaneously with a peak detection timing of a pulse detection signal obtained from the impedance converter having a small input impedance value.

5. A partial discharge detection apparatus of an electrical rotating machine, comprising:

at least two capacitors having equal or different capacitances and connected to a stator winding corresponding to one phase of three phases of an electrical rotating machine or a power line or neutral point lead line connected to a neutral point of three-phase stator windings;

at least two impedance converters having different input impedance values, each impedance converter having an input terminal electrically connected to the other terminal of a corresponding one of the capacitors and having an input impedance higher than an output impedance; and

signal processing means for receiving detection signals obtained from the impedance converters and determining, as a partial discharge signal, a pulse signal that is obtained from one of the impedance converters, which has a large input impedance value, simultaneously with a peak detection timing of a pulse detection signal obtained from the impedance converter having a small input impedance value.

10. A partial discharge detection method of an electrical rotating machine, comprising:

electrically connecting an output terminal of an electrical conductive element that has an electrostatic coupling of not more than 10 pF with a stator winding corresponding to one phase of three phases of an electrical rotating machine or a power line or neutral point lead line connected to a neutral point of stator windings and is in non-contact with the power line or neutral point lead line to an input terminal of an impedance converter having an input impedance of not less than 500 Ω and

an output impedance of 50 Ω

to 75 Ω

; and

detecting a partial discharge signal by processing a detection signal obtained from an output terminal of a transmission circuit which has a characteristic impedance of 50 Ω

to 75 Ω and

is connected to the output terminal of the impedance converter so as to match the impedances.

11. A partial discharge detection method of an electrical rotating machine which comprises:

two electrical conductive elements each of which has an electrostatic coupling of not more than 10 pF with a stator winding corresponding to one phase of three phases of the electrical rotating machine or a power line or neutral point lead line connected to a neutral point of stator windings and is in non-contact with the power line or neutral point lead line, a first impedance converter having an input impedance value of not less than 500 Ω and

an output impedance value of 50 Ω

to 75 Ω

, and a second impedance converter having an input impedance value of not less than 50,000 Ω

that is larger than that of the first impedance converter and an output impedance value of 50 Ω

to 75 Ω

;

characterized by electrically connecting one electrical conductive element to an input terminal of the first impedance converter and the other electrical conductive element to an input terminal of the second impedance converter; and

determining, as a partial discharge signal, a pulse signal that is output from the second impedance converter simultaneously with a peak detection timing of a pulse signal output from the first impedance converter.

12. A partial discharge detection method of an electrical rotating machine, comprising:

arranging at least one electrical conductive element or capacitor electrostatically coupled to a stator winding corresponding to one phase of three phases of an electrical rotating machine or a power line or neutral point lead line connected to a neutral point of stator windings and at least one coil magnetically coupled to the power line or neutral point lead line; and

detecting a partial discharge signal by discriminating a signal propagated from the electrical rotating machine from a signal propagated from outside the electrical rotating machine on the basis of whether a product of a polarity of an output signal peak from one of the impedance converter and a resistor connected to the electrical conductive element or the capacitor and a polarity of an output signal peak induced in the coil is positive or negative.

13. A partial discharge detection apparatus of an electrical rotating machine, comprising:

an electrical conductive element that is electrostatically coupled to a stator winding corresponding to one phase of three phases of an electrical rotating machine or a power line or neutral point lead line connected to a neutral point of three-phase stator windings and is in non-contact with the power line or neutral point lead line;

a parallel circuit including an electrical element having an electrostatic capacitance electrically connected to the other terminal of the electrical conductive element and an impedance converter having an input impedance higher than an output impedance; and

signal processing means for detecting a partial discharge pulse signal by processing a detection signal obtained from an output terminal of the impedance converter.

14. A partial discharge detection apparatus of an electrical rotating machine, comprising:

a capacitor connected to a stator winding corresponding to one phase of three phases of an electrical rotating machine or a power line or neutral point lead line connected to a neutral point of three-phase stator windings;

a parallel circuit including an electrical element having an electrostatic capacitance electrically connected to the other terminal of the capacitor and an impedance converter having an input impedance higher than an output impedance; and

signal processing means for detecting a partial discharge pulse signal by processing a detection signal obtained from an output terminal of the impedance converter.

15. A partial discharge detection method of an electrical rotating machine, comprising:

arranging, in a metal frame connected to a stator frame of an electrical rotating machine, one of a power line corresponding to a stator coil of three phases and a neutral point lead line connected to a neutral point of three-phase stator coils, the power line or neutral point lead line propagating a partial discharge signal generated by degradation of the stator coil in the stator frame;

installing two sensors each including a loop antenna around the power line or neutral point lead line while spacing the sensors apart by a predetermined distance and arranging the sensors or wiring signal lead lines from the sensors so as to cause peak values of output pulse waveforms from the signal lead lines connected to the sensors to have opposite polarities;

adjusting lengths of the signal lead lines of the sensors so as to cause a pulse signal which is induced by an electrical pulse signal propagated to the power line or neutral point lead line in a direction to enter the electrical rotating machine and output to a signal lead line terminal connected to the sensor far from the stator coil and a pulse signal which is induced by the pulse signal flowing to the power line or neutral point lead line and output to a signal lead line terminal connected to the sensor on a side of the stator coil to arrive at the same timing; and

detecting the partial discharge signal generated by degradation of the stator coil from a sum of pulse waveforms obtained through the two signal lead lines.