CN101044410B - Partial discharge detection apparatus and detection method of electrical rotating machine - Google Patents

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.

Description

The local discharge detection device of electric rotating machine and detection method

Technical field

The present invention relates to a kind of local discharge detection device and detection method of electric rotating machine.

Background technology

After the continuous working for a long time of high voltage electric rotating machine, the electrical insulation properties of motor internal constantly reduces owing to the stress of electricity, heat, machinery and environment.This will finally cause the dielectric breakdown and the fault of motor.

From the angle of reliability and operational administrative, inner insulation degradation need be monitored and diagnose to high voltage rotating machine.Especially, the stator winding of electric rotating machine is subjected to bigger electricity, heat and mechanical stress, and therefore, the insulation degradation of monitoring and diagnosis stator winding is extremely important.

In order to detect the insulation degradation in the stator winding, use the method for a kind of detection by the pulse-like signal that shelf depreciation caused of the insulation degradation generation of stator winding.Yet directly the shelf depreciation that detects in the coil that occurs in electric rotating machine inside is very difficult.

Usually, as open a for example day disclosure special permission communique spy flat 4-299048 disclosed, detecting sensor is installed in the stator winding, or attach it to the end space of electric rotating machine inside, so that when shelf depreciation takes place, detect electromagnetic wave of in electric rotating machine, propagating or the electric impulse signal that flows through coil, coil connecting line and power lead.

In the method, because position and the distance between the sensor that shelf depreciation takes place are very short, so detection sensitivity is very high and detection noise can be very little.Yet the installation of sensor must be carried out after removing coil, therefore loses time very much.In addition, sensor installation is relatively more difficult.

The diagnosis of insulation degradation is especially necessary for existing electric rotating machine of having worked decades.For this reason, need a kind ofly can easily add the partial discharge detecting sensor based that is installed to this existing electric rotating machine.

For example, day disclosure special permission communique spy opens flat 4-299050 and discloses a kind ofly by will being connected to the method that the high-voltage charging unit detects local discharge signal such as the direct detecting sensor of electrostatic condenser or current transformer, and described high-voltage charging unit is for example for the stator winding in the electric rotating machine or be connected to the power lead of electric rotating machine.

This detection method can be guaranteed high detection sensitivity.Yet, because higher electric stress is applied on the direct detecting sensor, so this sensor itself need have higher insulating property.

Summary of the invention

As mentioned above, in the detection method for local discharge of routine, the installation and measuring sensor needs artificial and time, and sensor itself need have higher insulating property.

The purpose of this invention is to provide a kind of detection method for local discharge and device, it can be easily mounted to high voltage component under contactless state, and guarantees higher detection sensitivity and accuracy of detection.

Local discharge detection device according to electric rotating machine of the present invention comprises: the metal frame that is connected to the stator frame of electric rotating machine; Power lead or neutral point lead-in wire, it is connected to the stator winding in the metal frame and is arranged in the metal frame to propagate the local discharge signal by the degeneration generation of stator winding; Sensor, it comprises flagpole antenna or tours antenna around the power lead that is installed in the metal frame or the neutral point lead-in wire, so that induction propagates into the local discharge signal of power lead or neutral point lead-in wire statically or on magnetic; And detecting device, it is received in the signal that produces in the sensor via signal lead, and detects shelf depreciation by signal Processing.

Detection method for local discharge according to electric rotating machine of the present invention comprises: in the metal frame of the stator frame that is connected to electric rotating machine, the power lead or the neutral point lead-in wire that are connected to corresponding to the stator winding of each phase in the three-phase in the metal frame are set; The sensor of two homophases is installed, wherein each sensor comprises flagpole antenna, tours antenna or each has a plurality of flagpole antennas that an end is electrically connected, for each phase of neutral point lead-in wire or power lead, on 2 o'clock, make the separately predetermined distance of two sensors at least simultaneously; And by relatively flowing through two length is identical or length difference is known and be connected to time of arrival poor (arrival time lag) of the signal output waveform that the signal lead of two sensors that are in homophase obtains, detect the local discharge signal of degenerating and producing by stator winding.

Local discharge detection device according to electric rotating machine of the present invention comprises: electrostatic coupling is to the power lead of the stator winding that is connected to electric rotating machine or neutral point lead-in wire and the conducting element that do not contact with power lead or neutral point lead-in wire; Has the input end of the terminal that is electrically connected to conducting element and input impedance impedance transformer greater than output impedance; And be used to handle the detection signal that obtains from the output terminal of impedance transformer to detect the signal processing apparatus of partial discharge pulse's signal.

Detection method for local discharge according to electric rotating machine of the present invention comprises: the input end that the output terminal of conducting element is electrically connected to impedance transformer, the electrostatic coupling of the power lead of wherein said conducting element and the stator winding that is connected to electric rotating machine or neutral point lead-in wire is not more than 10pF and does not contact with power lead or neutral point lead-in wire, and described impedance transformer has the input impedance that is not less than 500 Ω and the 50 Ω output impedance to 75 Ω; And detecting local discharge signal by handling the detection signal that obtains from the output terminal of transmission circuit, wherein said transmission circuit has 50 Ω to the characteristic impedance of 75 Ω and be connected to the output terminal of impedance transformer so that matched impedance.

Description of drawings

Figure 1A is the diagrammatic sketch that illustrates according to the local discharge detection device of the electric rotating machine of first embodiment of the invention, and this device has used the power lead that is connected to stator winding;

Figure 1B is the diagrammatic sketch that illustrates according to the local discharge detection device of the electric rotating machine of first embodiment of the invention, and this device has used the neutral point lead-in wire of the neutral point that is connected to stator winding;

Fig. 2 illustrates as according to the flagpole antenna of the sensor of first embodiment and the diagrammatic sketch of supporting construction thereof;

Fig. 3 is the block diagram that illustrates according to the formation example of the detecting device of first embodiment;

Fig. 4 illustrates output voltage waveforms so that explain the curve map of detector functions;

Fig. 5 be illustrate among first embodiment that is presented on the waveform observer the partial discharge pulse that propagates into conductor and by the oscillogram of the example of the detected waveform of flagpole antenna;

Fig. 6 illustrates as according to the tours antenna of the sensor of first embodiment and the diagrammatic sketch of supporting construction thereof;

Fig. 7 A is the axial, cross-sectional view that illustrates according to the local discharge detection device of the electric rotating machine of second embodiment of the invention;

Fig. 7 B is the longitudinal section view of the local discharge detection device of second embodiment;

Fig. 8 illustrates the oscillogram that concerns between flagpole antenna number among second embodiment and the antenna output voltage;

Fig. 9 be illustrate wherein will be arranged on the line at a plurality of flagpole antennas that a side is connected in series according to second embodiment or on a circular arc as the diagrammatic sketch of the example of sensor;

Figure 10 A is the axial, cross-sectional view that illustrates according to the local discharge detection device of the electric rotating machine of third embodiment of the invention;

Figure 10 B is the longitudinal section view according to this device of the 3rd embodiment;

Figure 11 A illustrates being used among the 3rd embodiment to receive to flow through and be connected resistor between electrode and the metal frame and arrive the axial, cross-sectional view that the connection of the high-frequency current of detecting device is provided with;

Figure 11 B illustrates the longitudinal section view that this connection that is used for receiving at the detecting device place high-frequency current of the resistor of flowing through is provided with;

Figure 12 be illustrate among the 3rd embodiment that shows by the waveform observer the partial discharge pulse that propagates into conductor and by the resistor that is connected to electrode the oscillogram of the example of detected waveform;

Figure 13 A illustrates being used among the 3rd embodiment to receive the axial, cross-sectional view that the connection from the high-frequency current of current transformer is provided with at the detecting device place, wherein described current transformer is inserted in the conductor of connection electrode and metal frame;

Figure 13 B illustrates this to be used in the longitudinal section view of detecting device place reception from the connection setting of the high-frequency current of current transformer;

Figure 14 A is the axial, cross-sectional view that a kind of setting among the 3rd embodiment is shown, and the electrode of cutting apart of arcuation wherein is set with one heart around power lead;

Figure 14 B is the longitudinal section view that this setting is shown, and the electrode of cutting apart of arcuation wherein is set with one heart around power lead;

Figure 15 A is the axial, cross-sectional view that illustrates according to the local discharge detection device of the electric rotating machine of fourth embodiment of the invention;

Figure 15 B is the longitudinal section view of the 4th embodiment;

Figure 16 A illustrates being used among the 4th embodiment to receive the axial, cross-sectional view that the connection from the high-frequency current of high-frequency current transformer is provided with at the detecting device place, wherein described high-frequency current transformer is inserted in the conductor of connection electrode and metal frame;

Figure 16 B illustrates this to be used in the longitudinal section view of detecting device place reception from the connection setting of the high-frequency current of high-frequency current transformer;

Figure 17 is the diagrammatic sketch that illustrates according to the local discharge detection device of the electric rotating machine of fifth embodiment of the invention;

Figure 18 illustrates that detection lead-in wire that passing through among the 5th embodiment will have equal length is connected to two sensors and by using the oscillogram of the pulse waveform that sync waveform scope observation output obtains;

Figure 19 is by once detecting the oscillogram of utilizing the pulse waveform that sync waveform scope observation output obtains when the direction that enters into electric rotating machine from the opposite side of electric rotating machine when pulse edge being shown propagating;

Figure 20 is the view that illustrates according to the local discharge detection device of the electric rotating machine of sixth embodiment of the invention;

Figure 21 is the oscillogram that the waveform that obtains when the signal edge enters the direction propagation of electric rotating machine among the 6th embodiment is shown;

Figure 22 is the oscillogram that the waveform that obtains when electric rotating machine propagates into the outside when signal is shown;

Figure 23 A is the longitdinal cross-section diagram that illustrates as according to the structure of the microstrip antenna of the sensor of seventh embodiment of the invention;

Figure 23 B is the sectional view of microstrip antenna;

Figure 24 is the equivalent circuit diagram of microstrip antenna;

Figure 25 illustrates the electric current I that the electromagnetic wave that passes through to propagate among this embodiment produces in microstrip antenna in the space ₀And I ₁The diagrammatic sketch of directivity;

Figure 26 is the diagrammatic sketch of the state of microstrip antenna that the 7th embodiment the is shown inside surface that is connected to metal frame;

Figure 27 is that the use of passing through that illustrates among the 7th embodiment is installed in the oscillogram that microstrip antenna between high-pressure conductor and the metal frame detects the waveform that shelf depreciation that the stator winding place produces obtains;

Figure 28 is the diagrammatic sketch that illustrates according to the local discharge detection device of the electric rotating machine of eighth embodiment of the invention;

Figure 29 is the expression observed from power lead or the neutral point lead-in wire equivalent circuit diagram according to the local discharge detection device of the 8th embodiment;

Figure 30 illustrates that the transmission line that will have characteristic impedance is directly connected to conducting element and the diagrammatic sketch that do not use the local discharge detection device of impedance transformer;

Figure 31 illustrates passing through the be connected in series equivalent circuit diagram of the circuit that forms of electrostatic capacitance and impedance among Figure 30;

Figure 32 is the oscillogram of comparison that the frequency characteristic of the setting of the 8th embodiment and the gain of the detection between the setting shown in Figure 30 is shown;

Figure 33 is the equivalent circuit diagram that the signal processor from the 8th embodiment is observed;

Figure 34 A is the oscillogram that the voltage waveform that obtains from transmission line one end is shown when the resistive terminator that is equivalent to transmission line is connected to the two ends of transmission line;

Figure 34 B illustrates when removing the resistive terminator from the two ends of transmission line so that the oscillogram of its voltage waveform that obtains from transmission line one end when opening;

Figure 35 A is the oscillogram that the example of the waveform when the detection method of being carried out by device shown in Figure 28 by use is observed partial discharge pulse is shown;

Figure 35 B is the oscillogram that the example of the waveform when the detection method of being carried out by device shown in Figure 30 by use is observed partial discharge pulse is shown;

Figure 36 is the diagrammatic sketch that illustrates according to the local discharge detection device of the electric rotating machine of ninth embodiment of the invention;

Figure 37 is the diagrammatic sketch that illustrates according to the measuring ability of two impedance transformers of ninth embodiment of the invention;

Figure 38 is the diagrammatic sketch that the generation frequency band of the transducer noise of the noise main cause when being considered to Partial Discharge Detection and the shelf depreciation waveform in the electric rotating machine is shown;

Figure 39 is the oscillogram that the signal waveform on the output terminal of the transmission path that appears at power lead and two impedance transformers among the 9th embodiment is shown;

Figure 40 is the diagrammatic sketch that the local discharge detection device of the electric rotating machine of the 10th embodiment according to the present invention is shown;

Figure 41 is required process of local discharge detection device and the diagrammatic sketch of time that installation the 10th embodiment according to the present invention is shown;

Figure 42 is the diagrammatic sketch that the local discharge detection device of the electric rotating machine of the 11st embodiment according to the present invention is shown;

Figure 43 is the diagrammatic sketch that the local discharge detection device of the electric rotating machine of the 12nd embodiment according to the present invention is shown;

Figure 44 is the function declaration figure that is used for distinguishing the pulse propagation direction of the signal processor that passes to the 12nd embodiment;

Figure 45 A be illustrate among the 12nd embodiment by the oscillogram that flows to from the stator winding of electric rotating machine that outside partial discharge pulse causes from the voltage waveform of the local discharge signal of two sensors;

Figure 45 B illustrates the oscillogram from the voltage waveform of the pulse of two sensors that causes to the noise spike of the stator winding of electric rotating machine by from outer flow;

Figure 46 is the diagrammatic sketch that the local discharge detection device of the electric rotating machine of the 13rd embodiment according to the present invention is shown;

Figure 47 is the equivalent circuit diagram that the local discharge detection device of the 13rd embodiment according to the present invention is shown from power lead or the observation of neutral point lead-in wire; And

Figure 48 is the curve map of comparison that the frequency characteristic of the detection gain between the present invention the 13rd embodiment and the setting shown in Figure 30 is shown.

Embodiment

Figure 1A is the diagrammatic sketch that illustrates according to the local discharge detection device of the electric rotating machine of first embodiment of the invention, and this device has used the power lead that is connected to stator winding.Figure 1B is the diagrammatic sketch that the local discharge detection device of electric rotating machine is shown, and this device has used the neutral point lead-in wire of the neutral point that is connected to stator winding.

Referring to Figure 1A and 1B, will be kept in the slit that is formed on (not shown) in the stator core corresponding to the stator winding 6 of the phase in the electric rotating machine three-phase (Figure 1A shows mutually with 1B), described stator core is installed to the inside surface of stator frame 7.

Cylindrical metal frame 5 is installed to stator frame 7.In Figure 1A, the insulation stent (not shown) is supporting the power lead 4 that is connected to stator winding 6.Power lead 4 is arranged on the central shaft of metal frame 5.In Figure 1B, the insulation stent (not shown) is supporting the neutral point lead-in wire 4 of the neutral point 6a that is connected to the threephase stator winding.Neutral point lead-in wire 4 is arranged on the central shaft of metal frame 5.With respect to power lead or neutral point lead-in wire 4 flagpole antenna 1 of being made and be used as sensor by conductive material is installed with contactless state.

In this case, flagpole antenna 1 is arranged to be parallel to power lead or neutral point lead-in wire 4, and is fixed on the antenna supports insulative member 8, this insulating component is installed on two suitable points of metal frame 5, as shown in Figure 2.

Signal lead 2 is connected to an end of flagpole antenna 1.Partial discharge pulse by signal lead 2 inputs is received by resistor or high-frequency current transformer (not shown) by detecting device 3.Necessary, the prime amplifier that is used for the signal amplification amplifies the partial discharge pulse that is input to detecting device 3.

As shown in Figure 3, detecting device 3 comprise have comparator circuit 51, the analog signal processing circuit 54 of gate circuit 52 and computing circuit 53, described computing circuit 53 comprises integrating circuit and peak detection circuit; Demonstration is from the display device 55 of the peak value output of analog signal processing circuit 54; The integrated value of self simulation signal processing circuit 54 output in the future is converted to the analog to digital conversion circuit 56 of numerical data; And storage is from the memory storage 57 of the output of analog to digital conversion circuit 56.

In having partial discharge pulse's pick-up unit of above-mentioned setting, when shelf depreciation took place the insulation degradation owing to stator winding 6, local discharge signal was transmitted to power lead or neutral point lead-in wire 4.

Local discharge signal from power lead or neutral point lead-in wire 4 by statically or electromagnetic ground sense flagpole antenna 1, and be input to detecting device 3 by resistor or high-frequency current transformer from signal lead 2.

In detecting device 3, comparator circuit 51 compares predetermined threshold 62 and signal waveform value 61, as shown in Figure 4.Gate circuit 52 neglects the signal that is equal to or less than threshold value.Gate circuit 52 is the section 63 interior signals that receive greater than threshold value at the fixed time.Peak detection circuit 53 test example are as the peak value 64 that occurs for the first time in the period at this section or the amplitude (integrated value) 65 of shelf depreciation.Detected value is presented on the display device 55 such as oscillographic waveform observation device or registering instrument.Analog to digital conversion circuit 56 is converted to digital value with peak value simultaneously, and this digital value is stored in the memory storage 57.

Fig. 5 illustrates the example that is presented at the waveform on the waveform finder, and these waveforms are to obtain by the partial discharge pulse that makes detecting device 3 and flagpole antenna 1 detection propagate into power lead or neutral point lead-in wire 4.As shown in Figure 5, propagate into power lead or neutral point lead-in wire 4 pulse signal 31 and in antenna, cause pulse waveform 32, this waveform have with lead in the first identical ripple of polarity of first ripple of propagation pulse.

Be presented at the identical pulse waveform of the polarity with first ripple on the waveform observation device by observation, can learn that partial discharge pulse occurs in the stator winding.

To be installed in the metal frame 5 as the flagpole antenna 1 of sensor under contactless state corresponding to power lead that is connected to stator winding 6 or neutral point lead-in wire 4.Detecting device 3 can receive and detect degeneration owing to stator winding produces and from power lead or neutral point lead-in wire 4 statically or electromagnetic ground sense the local discharge signal of telescopic antenna 1.There is no need to change the inside of electric rotating machine.Can be only power lead by changing electric rotating machine or the metal frame around the neutral point lead-in wire 4 and relatively easily non-contacting sensor is installed to high voltage component.

In the above-described embodiments, if the power lead or the neutral point lead-in wire 4 that are arranged in the metal frame 5 are the power leads that are connected to stator winding 6, then high pressure is applied near the antenna.Therefore, need relax electric field such as the insulating material cover antenna of epoxy resin or the end of handling antenna and concentrate by utilizing.

In the above-described embodiments, flagpole antenna 1 is as sensor.Tours antenna 9 shown in Figure 6 also can detect from the go between local discharge signal of 4 static or electromagnetic induction of power lead or neutral point.

In the above-described embodiments, flagpole antenna 1 or tours antenna 9 are mounted to are parallel to power lead or neutral point lead-in wire 4.Antenna can be arranged perpendicular to power lead or neutral point lead-in wire 4.

Fig. 7 A is the axial, cross-sectional view that illustrates according to the local discharge detection device of the electric rotating machine of second embodiment of the invention.Fig. 7 B is a longitudinal section view.The Reference numeral identical with Figure 1A, 1B and 2 represented identical parts in Fig. 7 A and 7B.

In a second embodiment, shown in Fig. 7 A and 7B, will be arranged on as a plurality of flagpole antennas 1 of sensor on the inside surface of metal frame 5, they are around power lead or neutral point lead-in wire 4 and have identical angle intervals.The antenna supports insulative member 8 that is fixed to metal frame 5 supports flagpole antenna 1.Bonding conductor 10 connects an end of each flagpole antenna 1 usually.Bonding conductor 10 is connected to detecting device 3 by signal lead 2.

Fig. 8 illustrates the relation between the number of flagpole antenna and detection sensitivity=(the primary peak value of the detection waveform of sensor)/(the primary peak value of the waveform of propagating by power lead or neutral point lead-in wire).

When the flagpole antenna number was 1, detection sensitivity was defined as 1.

Found out clearly that by chart shown in Figure 8 the number of flagpole antenna is many more, the output of sensor is high more.With in having being provided with an of flagpole antenna, compare, the detection sensitivity of sensor is higher in comprising being provided with of a plurality of flagpole antennas.

By this set, needn't change the inside of electric rotating machine, this is identical with first embodiment.Can only go between metal frame on every side and relatively easily non-contacting sensor is installed to high voltage component by power lead or the neutral point that changes electric rotating machine.In addition, can improve detection sensitivity.

In a second embodiment, a plurality of flagpole antennas 1 are arranged to circumferential.Perhaps, as shown in Figure 9, a plurality of flagpole antennas 1 (the latter half of Fig. 9) are set with one heart or a plurality of flagpole antennas 1 (the first half of Fig. 9) are set point-blank with respect to power lead or neutral point lead-in wire 4.Perhaps, as shown in Figure 9, the flagpole antenna of the first half is arranged to linear, and the flagpole antenna of the latter half is arranged to circular arc, vice versa.These settings even can produce function same as described above and effect.

Figure 10 A is the axial, cross-sectional view that illustrates according to the local discharge detection device of the electric rotating machine of third embodiment of the invention.Figure 10 B is its longitudinal section view.The Reference numeral identical with Figure 1A and 1B represented identical parts in Figure 10 A and 10B.

Referring to Figure 10 A and 10B, will be kept in the slit that is formed on (not shown) in the stator core corresponding to the stator winding 6 of a phase in the electric rotating machine three-phase (Figure 10 A illustrates mutually with 10B), described stator core is installed to the inside surface of stator frame 7.

Cylindrical metal frame 5 is installed to stator frame 7.The support and connection of insulation stent (not shown) are to the power lead or the neutral point lead-in wire 4 of stator winding 6.On power lead or neutral point lead-in wire 4 central shafts that are arranged in the metal frame 5.Around power lead or neutral point lead-in wire 4 cylinder electrode 11 of electrostatic coupling to power lead or neutral point lead-in wire 4 is set with one heart.In this case, electrode 11 is fixed on the electrode supporting insulating component 12, this member is installed on the suitable point of inside surface of metal frame 5.

Resistor 13 is connected between electrode 11 and the metal frame 5, shown in Figure 11 A and 11B.Signal lead 2 is connected to electrode side one end of resistor 13.Receive the high-frequency current that produces based on the partial discharge pulse of flowing through signal conductor 2 by detecting device 3 by resistor or current transformer (not shown).Necessary, the prime amplifier that is used for the signal amplification is amplified to detecting device 3 with partial discharge pulse's input.

The setting of detecting device 3 with in first embodiment, describe shown in Figure 3 be provided with identically, therefore will omit description to it.

In having partial discharge pulse's pick-up unit of above-mentioned setting, when shelf depreciation took place the insulation degradation owing to stator winding 6, local discharge signal propagated into power lead or neutral point lead-in wire 4.

Go between 4 the time when local discharge signal propagates into power lead or neutral point, flowing through greater than the local discharge signal of the high-frequency current of several KHz is connected resistor 13 between metal frame 5 and the electrode 11, and described electrode 11 electrostatic coupling are to power lead or neutral point lead-in wire 4.High-frequency current is input to detecting device 3 from signal lead 2 by resistor or current transformer (not shown).

Detecting device 3 can detect the signal in the optimum high frequency band by the signal Processing identical with the described signal Processing of first embodiment.

Figure 12 illustrates partial discharge pulse 33 and the resistor 13 detected waveforms 34 by being connected to electrode 11 that propagate into power lead or neutral point lead-in wire 4, with respect to power lead or neutral point lead-in wire 4 described electrode 11 is set with one heart.

From Figure 12, can obviously find out, propagate into power lead or neutral point lead-in wire 4 partial discharge pulse 33 and cause pulse waveform 34 in the testing circuit that comprises electrode 11 and resistor 13, this waveform has the first identical ripple of polarity of first ripple of the propagation pulse in polarity and the conductor.

By observation be presented on the waveform observation device have with first phase of wave with the pulse waveform of polarity, can learn that partial discharge pulse occurs in the stator winding.

Around power lead or neutral point lead-in wire 4, electrostatic coupling is set with one heart to being arranged in the metal frame 5 and being connected to the power lead of stator winding 6 or the cylinder electrode 11 of neutral point lead-in wire 4.Detecting device 3 receives and processing is flowed through be connected electrode 11 and metal frame 5 () between the high-frequency current of resistor 13.Therefore, detecting device 3 can detect the local discharge signal that the degeneration owing to stator winding produces.There is no need to change the inside of electric rotating machine.Can only go between metal frame on every side and relatively easily non-contacting sensor is installed to high voltage component by power lead or the neutral point that changes electric rotating machine.

In the above-described embodiments, detecting device 3 receive flow through be connected electrode 11 and metal frame 5 () between the high-frequency current of resistor 13.Perhaps, shown in Figure 13 A and 13B, high-frequency current transformer 14 can be inserted in connection electrode 11 and metal frame 5 () bonding conductor in.Detecting device 3 can receive by high-frequency current transformer 14 detected high-frequency currents.

In the above-described embodiments, around power lead or neutral point lead-in wire 4 cylinder electrode 11 of electrostatic coupling to power lead or neutral point lead-in wire 4 is set with one heart.Shown in Figure 14 A and 14B, also the cylinder electrode 11 axially can be divided into a plurality of have annular shape separately cut apart electrode 15, and be provided with one heart around power lead or neutral point lead-in wire 4 and cut apart electrode 15.In this case, can cut apart on the longitudinal direction that electrode 15 is arranged on power lead or neutral point lead-in wire 4 a plurality of.

This set makes can be adjusted high-frequency current transformer 14 and to cut apart electrostatic capacitance between the electrode 15, so that can detect the signal in the optimum high frequency band.

In the above-described embodiments, electric stress is applied to electrode surface.Therefore, can concentrate by utilizing the end of handling electrode to relax electric field such as the insulating material coated electrode surface or the appropriateness of epoxy resin.

Figure 15 A is the axial, cross-sectional view that illustrates according to the local discharge detection device of the electric rotating machine of fourth embodiment of the invention.Figure 15 B is a longitudinal section view.The Reference numeral identical with 11B with Figure 11 A represented identical parts in Figure 15 A and 15B.

In the 4th embodiment, shown in Figure 15 A and 15B, metal frame 5 is separated by radial cuts and at intermediate point.The cylinder electrode 16 that diameter is identical with metal frame is inserted into burble point and around power lead or neutral point lead-in wire 4 this cylinder electrode 16 is set with one heart.Two openends of cylinder electrode 16 are installed to the openend of the metal frame 5 of separation via ring electrode supports insulative member 17.The end of being arranged to cross over the bonding conductor 18 of electrode 16 is connected respectively to the metal frame 5 of separation.

Resistor 13 is connected between electrode 16 and the metal frame 15.Signal lead 2 is connected between electrode side one end and detecting device 3 of resistor 13, this detecting device 3 is configured to receive the high-frequency current of the resistor 13 of flowing through.

This set even permission are based on detecting shelf depreciation with the 3rd embodiment identical functions.Therefore need not to change the inner structure of electric rotating machine.Can only go between metal frame on every side and relatively easily non-contacting sensor is installed to high voltage component by power lead or the neutral point that changes electric rotating machine.

In the 4th embodiment, detecting device 3 receive flow through be connected electrode 16 and metal frame 5 () between the high-frequency current of resistor 13.Perhaps, shown in Figure 16 A and 16B, high-frequency current transformer 14 can be coupled to be connected electrode 16 and metal frame 5 () between conductor.Detecting device 3 can receive by high-frequency current transformer 14 detected high-frequency currents.

Figure 17 is the diagrammatic sketch that illustrates according to the local discharge detection device of the electric rotating machine of fifth embodiment of the invention.The Reference numeral identical with Figure 1A and 1B represented identical parts in Figure 17.

Referring to Figure 17, will be kept in the slit that is formed on (not shown) in the stator core corresponding to the stator winding 6 of the phase in the electric rotating machine three-phase (Figure 17 shows a phase), described stator core is installed to the inside surface of stator frame 7.

Cylindrical metal frame 5 is installed to stator frame 7.The support and connection of insulation stent (not shown) are to the power lead 4 of stator winding 6.Power lead 4 is arranged on the central shaft in the metal frame 5.Perhaps, the support and connection of insulation stent (not shown) are to the neutral point lead-in wire 4 of the neutral point of threephase stator winding 6.On neutral point lead-in wire 4 central shafts that are arranged in the metal frame 5.

For each phase of power lead or neutral point lead-in wire 4, the sensor 21 and 22 that comprises flagpole antenna separately corresponding to power lead or 4 installations of neutral point lead-in wire at 2 A and the B place of preset distance separately.Output and comparison waveform that waveform comparator 23 receives from sensor 21 and 22.Can come observations by using the waveform observation device.

Figure 18 illustrates by sensor 21 waveform observation device when 22 are connected to waveform comparator 23 and have in the local discharge detection device of above-mentioned setting by utilization via the identical detection of length lead-in wire is observed the waveform that output obtains.Figure 19 illustrates the pulse waveform that obtains along the pulse of the direction propagation that enters into electric rotating machine from its opposition side by detecting.Referring to Figure 18 and 19, horizontal ordinate express time, ordinate are represented waveform output (amplitude).

Go between 4 the time when pulse propagates into power lead or neutral point from electric rotating machine, at first observe output waveform 35, pass through the delay of several nanoseconds then, observe output waveform 36 again, as shown in figure 18 from sensor 22 from sensor 21.Go between 4 the time when pulse propagates into power lead or neutral point from power-supply system, at first observe output waveform 39, pass through the delay of several nanoseconds then, observe output waveform 38 again, as shown in figure 19 from sensor 21 from sensor 22.

The time delay 37 of several nanoseconds and 40 is corresponding to the pulse propagation time between sensor 21 and 22.Therefore, can differ from 37 or 40 time of arrival by the waveform between detecting sensor 21 and 22 and estimate the pulse propagation direction.

Must make sensor 21 and open such distance in 22 minutes: can discern the waveform mistiming between them.

For example, about 1/4 of the time width of first half-wave of the first forward position pulse signal (for example 35) time width makes the waveform observation device easily to discern and arrives the mistiming.Therefore, when the frequency of pulse signal was 10MHz, necessity distance between sensor mounting points A and the B was about 4m.

The frequency of signal is low more, and pulse waveform is long more oscillation period.Differ from 37 and 40 time of arrival in order accurately to detect pulse waveform, the distance between the sensor 21 and 22 must be grown.

Usually, the signal that comprises local discharge signal is propagated from electric rotating machine, and noise mainly is to propagate from power-supply system one side opposite with generator one side.Therefore, can separate with power-supply system by the waveform official post time of arrival noise between the survey sensor 21 and 22.

Because sensor 21 is near the stator winding 6 as Partial Discharge Sources, therefore above-mentioned the setting can be improved Partial Discharge Detection sensitivity.

Even when being connected to the signal lead of sensor 21 and having different length,, also can when pulse detection, proofread and correct if this length is known with 22.Therefore, as mentioned above, noise is separated with power-supply system.

In this embodiment, for each phase of power lead or neutral point lead-in wire 4, at two sensor installations 21 and 22 on the point of preset distance separately, described metal frame is preserved power lead or the neutral point lead-in wire 4 that is connected to electric rotating machine in metal frame 5.Can detect shelf depreciation by measuring from two differences time of arrival that are installed between the same signal of sensor waveform in mutually.Need not to change the inside of electric rotating machine.Can only go between metal frame on every side and relatively easily non-contacting sensor is installed to high voltage component by power lead or the neutral point that changes electric rotating machine.In addition, can make from the noise spike of power-supply system and pulse separation from electric rotating machine.Therefore, can accurately detect shelf depreciation.

In the 5th embodiment, two sensors 21 and 22 that comprise flagpole antenna separately are installed.Two sensors that comprise the flagpole antenna that a tours antenna or an a plurality of end are electrically connected separately can be installed.

Figure 20 is the diagrammatic sketch that illustrates according to the local discharge detection device of the electric rotating machine of sixth embodiment of the invention.The Reference numeral identical with Figure 1A and 1B represented identical parts in Figure 20.

Referring to Figure 20, will be kept in the slit that is formed in the stator core (not shown) corresponding to the stator winding 6 of the phase in the electric rotating machine three-phase (Figure 20 shows a phase), described stator core is installed to the inside surface of stator frame 7.

Cylindrical metal frame 5 is installed to stator frame 7.Insulation stent (not shown) supportive conductors 4a, the bus that for example is separated, coil bonding conductor or neutral point lead-in wire, wherein partial discharge pulse's signal propagates into described neutral point lead-in wire.Conductor 4a is arranged on the central shaft in the metal frame 5.

Two tours antennas 24 and 25 are arranged on the some A and some B that separates preset distance with identical direction along conductor 4a.Be provided with in the opposite direction being connected to the terminal Aa of signal lead of tours antenna 24 and 25 and Ab and terminal Ba and Bb, make that the primary peak value from the output waveform of the signal lead of tours antenna has opposite polarity.

In addition, be provided with the length that is connected to away from the signal lead of the tours antenna 25 of electric rotating machine longer, make when on pulse is entering the direction of electric rotating machine, flowing through conductor 4a to have identical timing with the output waveform that between terminal Ba and Bb, produces in the output waveform that produces between terminal Aa and the Ab.That is to say, make the signal lead of tours antenna 25 longer, make the signal propagation time of signal lead of tours antenna 25 become longer than the signal propagation time of the signal lead of tours antenna 24, the time that grows is that the signal propagation time between tours antenna 24 and 25 is poor.

Connect signal lead to have the pulse voltage of opposite polarity corresponding to single propagation DISCHARGE PULSES EXTRACTION.Signal processor 26 receives from the voltage signal of the opposite polarity pulse waveform sum of conduct of points of common connection X and Y acquisition.Can be by using waveform observation device observations.

Figure 21 be illustrated in the local discharge detection device with above-mentioned setting when signal upload sowing time in the direction that enters electric rotating machine, from the example of output waveform and the two waveform sums of terminal Aa-Ab and Bb-Ba.

Referring to Figure 21, the viewed voltage waveform of Reference numeral 41 expression cross-over connection terminal Aa-Ab, the viewed voltage waveform of 42 expression cross-over connection terminal Ba-Bb, and 43 expression voltage waveforms 41 and 42 and waveform.

Figure 22 illustrate when signal when electric rotating machine propagates into the outside, at the example of terminal Aa-Ab and the observed output waveform of Ba-Bb and these two waveform sums.

Referring to Figure 22, Reference numeral 44 is illustrated in the observed voltage waveform in terminal Aa-Ab place; 45 are illustrated in the observed waveform in terminal Ba-Bb place; And 46 the expression voltage waveforms 44 and 45 and waveform.

As shown in figure 22, the first half-wave peak value of the pulse waveform propagated from electric rotating machine of tours antenna 24 and 25 waveform and keeping.Yet, be cancelled at the first half-wave peak value that enters the pulse waveform of propagating on the direction of electric rotating machine.

In order to keep waveform shown in Figure 22 and 46 first half-wave when electric rotating machine propagates into the outside when pulse, tours antenna 24 and 25 must have the distance corresponding to the time width of first half-wave of waveform and 46.

For example, when the frequency of pulse signal (for example waveform among Figure 21 41) was 10MHz, necessity distance between the tours antenna 24 and 25 was about 7m.Usually, the signal that comprises local discharge signal is propagated from electric rotating machine, and noise is mainly propagated from power-supply system.Therefore, can separate the noise of propagating from system.

In the above-described embodiments, be provided with in the opposite direction being connected to setting tours antenna 24 and the terminal Aa of 25 signal lead and Ab and terminal Ba and Bb in the same direction, make that the primary peak value from the output waveform of the signal lead of tours antenna has opposite polarity.Perhaps, tours antenna 24 and 25 can be provided with in the opposite direction, with induced voltage in the opposite direction.

As mentioned above, in this embodiment, make tours antenna 24 and opened predetermined distance in 25 minutes, and it is arranged in the metal frame 5 of preserving conductor 4a, conductor 4a is for example for the bus that is separated, coil bonding conductor or propagate the neutral point lead-in wire of the electric rotating machine of partial discharge pulse's signal.The peak value that will be arranged so that the output pulse waveform that obtains from the signal lead that is connected to antenna from the signal lead of antenna has opposite polarity.Adjust this be arranged so that output to be connected to away from the pulse of the signal lead terminal of the antenna of the stator winding of electric rotating machine with output to the pulse that is connected near the signal lead terminal of the antenna of the stator winding of electric rotating machine and arrive in the identical time.Signal processor 26 is received in the pulse signal of responding in two antennas, and detects the pulse waveform sum.Need not to change the inside setting of electric rotating machine.Can only relatively easily non-contacting sensor be installed to high voltage component by the metal frame around the change conductor 4a.In addition, can improve detection sensitivity.

In the 6th embodiment, two tours antennas 24 and 25 are installed.Two groups of a plurality of tours antennas that are connected in series can be installed.This set even can produce function same as described above and effect.

Figure 23 A is the longitdinal cross-section diagram that illustrates as the microstrip antenna structure of sensor, and described sensor is used for the local discharge detection device according to the electric rotating machine of seventh embodiment of the invention.Figure 23 B is a sectional view.

Referring to Figure 23 A and 23B, concentric cable 61 has the characteristic impedance of 50 Ω.Concentric cable 61 comprises the resistive terminator 62 of plate part and 50 Ω.Plate part has the three-decker that comprises insulating material 64 and be formed on the transmission line 65 on the plate electrode 63.Insulation course 66 covers this structure.

The characteristic impedance that is provided with between definite transmission line 65 and the plate electrode 63 according to geometry is 50 Ω, promptly equals the characteristic impedance of terminator 62.

The characteristic impedance that has 50 Ω as the concentric cable of signal lead use.Dull and stereotyped transmission line 65 is connected to the center line of concentric cable 60.Plate electrode 63 is connected to the coaxial cable shield line.

Prevent that as the concentric cable of signal lead noise from mixing with parts on every side except that antenna.

Figure 24 illustrates the equivalent electrical circuit of the microstrip antenna shown in Figure 23 A and the 23B.

Referring to Figure 24, the characteristic impedance of Reference numeral 67 expression concentric cable; The electromagnetic electric field component of 68 expressions; The electromagnetic magnetic-field component of 69 expressions.Represent with θ by the angle that transmission line 65 and the electromagnetic wave propagation direction 70 by spatial transmission form.

Figure 25 illustrates the electric current I that is generated by the electromagnetic wave of propagating in microstrip antenna in the space ₀And I ₁Directivity.

When the angle that is formed with respect to the electromagnetic wave propagation direction by transmission line 65 is 0 °, the little band edge electric current I that in concentric cable 61, produces ₀Sensitivity be maximized.In other words, the output of concentric cable is maximized with respect to the electromagnetic wave of propagating along the direction of concentric cable 61.

In the stator frame of rotation electrode, perhaps be connected to the power lead of stator winding or be connected in the metal frame volume inside of neutral point lead-in wire of stator winding of electric rotating machine in preservation, in case shelf depreciation takes place on stator winding, then electromagnetic wave is blazed abroad.

Therefore, the microstrip antenna 60 (as shown in figure 26) with said structure is installed on the inside surface of metal frame 5, can be detected local discharge signal with higher sensitivity by direction along stator winding.

Figure 27 illustrates by being installed in above-mentioned microstrip antenna 60 between high-pressure conductor and the metal frame and detecting the oscillogram of the waveform that the shelf depreciation of stator winding obtains.

As from waveform shown in Figure 27, can obviously finding out, because partial discharge pulse's signal 71 produces pulse waveform 72 in being connected to the concentric cable of antenna, so can detect local discharge signal.

If frame of electric rotating machine 7 or metal frame 5 have electromagnetic-wave leakage to outside part, then can detect shelf depreciation by on outside surface, microstrip line being installed near the frame of this part.

As mentioned above, in this embodiment, be installed on the inside surface of stator frame of electric rotating machine or the outside surface by the microstrip antenna 60 that an end is connected to resistive terminator 62 and comprises plate electrode 63, insulating material 64 and transmission line 65 or be installed in the power lead of preserving the stator winding that is connected to electric rotating machine or the inside surface or outside surface of the metal frame of neutral point lead-in wire on, can detect shelf depreciation.Needn't change the inside of electric rotating machine.Can only go between metal frame on every side and relatively easily non-contacting sensor is installed to high voltage component by power lead or the neutral point that changes electric rotating machine.

In the 7th embodiment, utilize the directivity of antenna, a plurality of microstrip antennas 60 can be installed in the metal frame or stator frame of electric rotating machine.When because during the degeneration generation shelf depreciation of stator winding, electromagnetic wave is propagated by the space between stator winding and the stator frame.From detecting the signal intensity of electromagnetic antenna output, can determine Partial Discharge Sources by relatively.

Figure 28 is the diagrammatic sketch that illustrates according to the local discharge detection device of the electric rotating machine of eighth embodiment of the invention.

Referring to Figure 28, will be kept in the slit that is formed on (not shown) in the stator core corresponding to the stator winding or the winding 101 of the phase in the electric rotating machine three-phase (Figure 28 shows a phase), described stator core is installed to the inside surface of stator frame 100.Power lead 102 is connected to the stator winding 101 of each phase.Perhaps, neutral point lead-in wire 102 can be connected to the neutral point of threephase stator winding.The supporting member (not shown) supports contactless conducting element 103, and this element is made by copper or aluminium and electrostatic coupling goes between 102 to power lead or neutral point.

The input end 106 of impedance transformer 105 104 is electrically connected to conducting element 103 via lead-in wire, in described impedance transformer 105 at least input impedance Zin greater than output impedance Zout.By with detection signal from transmission line 108 (characteristic impedance Z ₀) output terminal 109 be input to signal processor 110, detect partial discharge pulse's signal.Output terminal 109 is connected to the output terminal 107 of impedance transformer 105, so that matched impedance.

108 common use characteristic impedances are the concentric cable of 50 Ω or 75 Ω as transmission line.Therefore, Zout is generally 50 Ω or 75 Ω.

Next will the function of the local discharge detection device of electric rotating machine with above-mentioned setting be described.

Figure 29 illustrates the equivalent electrical circuit that power lead from Figure 28 or neutral point lead-in wire 102 are observed.Power lead or neutral point lead-in wire 102 are connected in series to the input impedance Zi and the electrostatic capacitance C of impedance transformer 105, and are grounding to earth point 111.The output V of the output terminal 107 of impedance transformer 105 _oAnd the ratio that flows between power lead or neutral point lead-in wire 102 the AC voltage peak Vi is provided by following formula:

$\mathrm{Vo}/\mathrm{Vi}=1/\sqrt{\{1+{[1/\left(2\mathrm{\πfCZin}\right)]}^2\}}---\left(1\right)$

Figure 30 illustrates and is configured to and will has characteristic impedance Z ₀Transmission line 108 be directly connected to conducting element 103 and do not use the setting of impedance transducer.

Figure 31 illustrates by with electrostatic capacitance C among Figure 30 and characteristic impedance Z ₀The equivalent electrical circuit that is connected in series and forms.The output V of test side 114 _oProvide by following formula with the ratio of the AC voltage peak Vi that flows to power lead or neutral point lead-in wire 102:

$\mathrm{Vo}/\mathrm{Vi}=1/\sqrt{\{1+{[1/\left({2\mathrm{\πfCZ}}_0\right)]}^2\}}---\left(2\right)$

108 common use characteristic impedances are the concentric cable of 50 Ω or 75 Ω as transmission line.

Figure 32 illustrates frequency characteristic 117 (20*Log (Vo/Vin)) in Figure 28 and 29 and the frequency characteristic 116 in Figure 30 and 31, wherein said frequency characteristic 117 is by using input impedance Zin to be higher than the impedance transformer of Zout, and by setting C=1pF, Zin=50k Ω, and Zout=50 Ω obtains, and described frequency characteristic 116 is by setting C=1pF and Z0=50 Ω and not using impedance transformer to obtain.

Wherein electrostatic capacitance and impedance form Hi-pass filter.

As from Figure 32, can obviously finding out, and in the detection method of not using impedance transformer shown in Figure 30, compare, it is bigger to be connected in the detection method of impedance transformer 105 of conducting element 103 output gain in use shown in Figure 28.

Figure 33 illustrates the equivalent electrical circuit that the signal processor 110 from Figure 28 is observed.Equal characteristic impedance Z ₀Resistance value (Z ₀) two ends of 118 termination transmission lines 108, be reflected in the transmission line 108 signal of propagating to prevent two ends 107 and 109.

Figure 34 A and 34B illustrate the oscillogram that prevents in the effect of end reflection.Figure 34 A illustrates when equaling characteristic impedance Z ₀Terminator (Z ₀) the 118 termination two ends 107 of transmission lines 108 and 109 o'clock, the waveform voltage signal 119 that obtains from terminal 109.

Figure 34 B illustrates when removing terminator (Z from the two ends of transmission line 108 ₀) 118 so that its waveform 122 that obtains when open, from terminal 109.Waveform 122 is by will be directly inputted to terminal 109 waveform 120 that obtains and voltage waveform 121 sums that appear on the terminal 109 from the waveform of terminal 107 outputs after time T, wherein waveform is reflected fully by terminal 109 during time T, propagate by transmission line 108, reflected by terminal 107 again, and propagate by transmission line 108.The length that depends on transmission line 108, travel-time T shortens, and generation and original waveform 120 have the output waveform of a great difference.

That is to say, when with the output impedance Zout of impedance transformer shown in Figure 28 105, the characteristic impedance Z of transmission line 108 ₀, and the input impedance of signal processor 110 (Zout=Z when being set to equate ₀), waveform accurately can be sent to signal processor 110.

Figure 35 A illustrates by using the example of the observed partial discharge pulse of detection method among Figure 28.Local discharge signal 125,126 expressions that Reference numeral 124 expressions among Figure 35 A flow to power lead output to the signal that transmits line end 108.In Figure 35 A, can accurately detect partial discharge pulse's waveform 127.Figure 35 B illustrates by using the example of the observed partial discharge pulse of detection method among Figure 30.Reference numeral 128 expressions among Figure 35 B flow to the output signal of local discharge signal 129,130 expressions of power lead from the transmission line end, and its peak value of pulse is less than local discharge signal 129.

In the above-described embodiments, the conducting element of electrostatic coupling to power lead or neutral point lead-in wire 102 is set under contactless state, the stator winding that described power lead or neutral point lead-in wire 102 are connected to electric rotating machine connects.Even, also can detect shelf depreciation as mentioned above by providing the capacitor that is connected to power lead or neutral point lead-in wire 102 to replace conducting element.

In local discharge detection device according to the electric rotating machine of the 8th embodiment, electrostatic coupling is in an end of the conducting element 103 contactless state under or is connected to power lead or a go between end of 102 capacitor of neutral point is electrically connected to the input end of input impedance greater than the impedance transducer of output impedance to power lead 102 or neutral point lead-in wire 102 and with respect to it, wherein said power lead 102 is connected to the stator winding corresponding to the phase in the electric rotating machine three-phase, and described neutral point lead-in wire 102 is connected to the neutral point of threephase stator winding.Detect partial discharge pulse's signal from the output terminal of impedance transducer or the output terminal of transmission circuit, described transmission circuit is connected to the output terminal of impedance transducer so that matched impedance.Needn't change the inside of electric rotating machine.Can only go between metal frame on every side and relatively easily non-contacting sensor is installed to high voltage component by power lead or the neutral point that changes electric rotating machine.In addition, can detect shelf depreciation with higher detection sensitivity and degree of accuracy.

Figure 36 is the diagrammatic sketch that illustrates according to the local discharge detection device of the electric rotating machine of ninth embodiment of the invention.

Referring to Figure 36, power lead 102 is connected to the stator winding 101 corresponding to the phase in the electric rotating machine three-phase.Perhaps, neutral point lead-in wire 102 can be connected to the neutral point of threephase stator winding 101.At least two conducting elements 103 with 138 via lead-in wire 104 and 140 be electrically connected to two have different input impedance values and wherein at least input impedance greater than the impedance transducer 105 of output impedance and 132 input end 106 and 133, described at least two conducting elements 103 and 138 and power lead or neutral point lead-in wire 102 have the identical or different electrostatic coupling of electric capacity, and do not contact with power lead or neutral point lead-in wire 102.Detect partial discharge pulse's signal by detection signal is input to signal processor 137 from the output terminal 109 and 136 of transmission line 108 and 135, described transmission line 108 and 135 is connected to the output terminal 107 and 134 of impedance transducer 105 and 132 so that matched impedance.

As shown in figure 37, signal processor 137 has the peak value of determining from the pulse signal of output terminal 107 outputs of impedance transducer 105 and detects function (S1) constantly, wherein said impedance transducer 105 has less input impedance value, and having the function (S2) that the pulse signal that will export from the output terminal 134 of impedance transducer 132 is defined as local discharge signal, wherein said impedance transducer 132 has bigger input impedance value.

Figure 38 is the diagrammatic sketch that the generation frequency band of the transducer noise of the noise factor when being construed to be Partial Discharge Detection and the shelf depreciation waveform in the electric rotating machine is shown.The transducer noise generally includes the frequency up to several MHz.Yet local discharge signal comprises several MHz or higher frequency.

The Hi-pass filter that the input impedance Zin of impedance transformer 105 and electrostatic capacitance C formation only allow the high fdrequency component of signal to pass through, shown in figure 32.The cutoff frequency of Hi-pass filter is provided by following formula

fc＝1/2πZ _inC (3)

When the input impedance value of selecting impedance transformer 105 makes cutoff frequency I be present in the frequency band of 10MHz at least, wherein have only the local discharge signal component to exist, only export partial discharge pulse from the output terminal 107 of impedance transformer shown in Figure 38 105.

Yet as shown in figure 38, shelf depreciation comprises the wideband component sometimes in a pulse.Therefore, can not be reproduced in the accurate discharge waveform that flows in the power lead by the output of impedance transformer 105.In the time will hanging down cutoff frequency (cutoff frequency II) and be set to reach the frequency band that noise exists, as shown in figure 38, can detect accurate shelf depreciation waveform.

The waveform 141 at output terminal 109 places of the transmission line 108 that Figure 39 illustrates the local discharge signal 139 that flows to power lead, appear at impedance transformer 105 and the waveform 143 at output terminal 136 places that appears at the transmission line of impedance transformer 132, wherein select the impedance of described impedance transformer 105 to make cutoff frequency I be present in the frequency band that wherein only produces shelf depreciation, described impedance transformer 132 has the cutoff frequency II that is present in the low-frequency band that comprises noise.

As can obviously finding out from Figure 39, output terminal 107 outputs of impedance transformer 105 only comprise the shelf depreciation waveform 141 of the high fdrequency component of shelf depreciation.The output terminal 134 of impedance transformer 132 is accurately exported shelf depreciation waveform 143.

Yet, because low frequency region comprises the transducer noise probably, as shown in figure 38, therefore the walkaway mistake takes place.

Generation by using the shelf depreciation waveform that is detected by impedance transformer 105 is as triggering, signal processor 137 receives the waveform that is detected by the impedance transformer 132 with low cutoff frequency, wherein said impedance transformer 105 has the cutoff frequency of the frequency band that only detects shelf depreciation, as shown in figure 37.This allows to remove denoising and accurately receives local discharge waveform.

In the above-described embodiments, electrostatic coupling is arranged under the contactless state to the power lead 102 of the stator winding that is connected to electric rotating machine or two conducting elements 103 and 138 of neutral point lead-in wire 102.Even by providing the capacitor that is connected to power lead or neutral point lead-in wire 102 to replace conducting element 103 and 138, also can be to remove denoising and accurately to receive local discharge waveform to above-mentioned similar mode.

In the ninth embodiment of the present invention, power lead is connected to the stator winding corresponding to the phase in the electric rotating machine three-phase.Perhaps, the neutral point lead-in wire can be connected to the neutral point of threephase stator winding.In at least two conducting elements each or at least two are connected to corresponding in the input end that in the capacitor of power lead or neutral point lead-in wire each is electrically connected to two impedance transformers, wherein said at least two conducting elements and power lead or neutral point lead-in wire have the identical or different electrostatic coupling of electric capacity and do not contact with power lead or neutral point lead-in wire, described two impedance transformers have different input impedance values and in described two impedance transformers input impedance greater than output impedance.Detecting the constantly identical moment with the peak value of the pulse signal of the output of impedance transformer with less input impedance value, will be by an input impedance value in two impedance transformers the pulse signal that produces of the output terminal of bigger impedance transformer be defined as local discharge signal.Needn't change the inside of electric rotating machine.Can only go between metal frame on every side and relatively easily non-contacting sensor is installed to high voltage component by power lead or the neutral point that changes electric rotating machine.In addition, can detect shelf depreciation with higher detection sensitivity and degree of accuracy.

Figure 40 is the diagrammatic sketch that the local discharge detection device of the electric rotating machine of the 10th embodiment according to the present invention is shown.

Referring to Figure 40, power lead 102 is connected to the stator winding corresponding to the phase in the electric rotating machine three-phase, and perhaps neutral point lead-in wire 102 is connected to the neutral point of threephase stator winding.The conduction rack 151 that will have rectangular parallelepiped protrusion part shape or a cylindrical shape be arranged on power lead or neutral point lead-in wire 102 around.

Conduction rack 151 has view window 142.Insulcrete 144 flat or circle is fixed on the view window 142.The front surface of insulcrete 144 or anti-surface support conducting element 145, these conducting element 145 electrostatic coupling go between 102 to power lead or neutral point, and do not contact with power lead or neutral point lead-in wire 102.In addition, insulcrete 144 upper supports wherein at least input impedance greater than the impedance transformer 147 of output impedance.Impedance transformer 147 is connected to signal processor 150 via transmission line 148.

Be connected to the conducting element 145 of electrostatic coupling according to the impedance transformer 147 of wanting detected frequency band to select to power lead or neutral point lead-in wire 102, to form Hi-pass filter on the front surface of the insulcrete 144 of the view window 142 that is fixed to conduction rack 151 or anti-surface, this Hi-pass filter is represented by the equivalent electrical circuit shown in Figure 29 and 31.Allow to detect partial discharge pulse like this.

Figure 41 illustrates and installs required process and the time of local discharge detection device.In conventional method, often will be installed in the frame as partial discharge detecting sensor based as the coupling condenser of conventional sensors.In order during operation this sensor to be installed to electric rotating machine, need carry out following steps: the operation of the motor that stops the rotation, near mounting points, separate this, sensor installation and circuit, and near mounting points, reinstall this.

Yet, in shown in Figure 40 the setting, the insulcrete 144 that supports conducting element 145 and impedance transformer 147 is installed in the opening of view window.For sensor installation, following steps are essential and enough: the motor that stops the rotation makes insulcrete 144 separate with view window, and insulcrete 144 is installed on the opening of view window.Compare with conventional method, this can simplify step, reduces the tie-time.

As mentioned above, in the 10th embodiment of the present invention, the conduction rack 151 that will have rectangular parallelepiped protrusion part shape or cylindrical shape and have a view window be arranged on electric rotating machine stator winding around.The opening of the view window of conduction rack 151 is supports insulative plate 144 separably, on this insulcrete 144 fixing not with power lead or neutral point lead-in wire 102 conducting elements that contact 145 and be connected to conducting element 145 and input impedance greater than the impedance transformer 147 of output impedance.Therefore, the Partial Discharge Detection unit can easily be installed at short notice.

In the 10th embodiment, with conduction rack 151 be arranged on power lead or neutral point lead-in wire 102 around, as shown in figure 40.For example, in power generator, detection conducting element 145 is set in the frame that covers power lead or neutral point lead-in wire 102 can reduces insulation characterisitic with power lead or neutral point lead-in wire 102 and grounding rack structure.In order to prevent the generation of this situation, conducting element 145 is installed on the view window 142 of frame.

In this case, the distance between conducting element 145 and power lead or the neutral point lead-in wire 102 is about several decimeters, though this also depends on device.View window 142 is of a size of several decimeters * several decimeters.Therefore, in that (specific inductive capacity 8.85pF/m * conducting element is towards the estimated area 0.1 * 0.1m of power lead ²Between/conducting element and the power lead apart from 0.1m) the basis on, electrostatic capacitance C is approximately 1pF.

The input impedance Zin that supposes to be connected to the impedance transformer 147 of conducting element 145 is 50,000 Ω or bigger, and wherein said conducting element has aforesaid electrostatic coupling.According to equation (3) cutoff frequency is about 3MHz.For this reason, accurate Partial Discharge Detection not affected by noise is possible in corresponding to the detection band of the frequency band of several MHz, and the transducer noise reduces in described frequency band, as shown in figure 38.

In detection method for local discharge shown in Figure 40, view window 142 can be bigger, and perhaps the distance between conducting element 145 and the power lead 102 can be shorter in some cases.If suppose electrostatic coupling, then be made as 5,000 Ω or the bigger cutoff frequency that can obtain about 3MHz by input impedance with impedance transformer 147 up to 10pF.

148 common use characteristic impedances are the concentric cable of 50 Ω or 75 Ω as transmission line.For impedance matching, the output impedance of impedance transformer 147 is made as 50 Ω or 75 Ω.

As mentioned above, power lead 102 is connected to the stator winding corresponding to the phase in the electric rotating machine three-phase.Perhaps, neutral point lead-in wire 102 can be connected to the neutral point of threephase stator winding.The conducting element that has 10pF or littler electrostatic coupling with power lead or neutral point lead-in wire 102 and do not contact with power lead or neutral point lead-in wire is electrically connected to the input end of the impedance transformer with 5,000 Ω or bigger input impedance.From the output terminal of the impedance transformer of output impedance with 50 Ω or 75 Ω, perhaps from characteristic impedance with 50 Ω or 75 Ω and the output terminal that is connected to impedance transformer so that the output terminal of the transmission circuit of matched impedance detects partial discharge pulse's signal.This makes it possible to carry out Partial Discharge Detection with higher detection sensitivity and degree of accuracy.

Even in this embodiment, as mentioned above, can be by providing capacitor to replace conducting element 145 to remove denoising and accurately receiving local discharge waveform.

Figure 42 is the diagrammatic sketch that the local discharge detection device of the electric rotating machine of the 13rd embodiment according to the present invention is shown.

As shown in figure 42, for example, in power generator, a plurality of detection conducting elements 152 and 153 are set in the frame 151 that covers power lead or neutral point lead-in wire 102 can reduce insulation characterisitic with power lead or neutral point lead-in wire 102 and conduction rack 151.In order to prevent this from occurring, a plurality of detection conducting elements 152 and 153 are arranged on the view window 142 of frame.

In this case, detect the distance that conducting element 152 and 153 goes between between 102 with power lead or neutral point and be approximately several decimeters, although this also will depend on device.View window 142 is of a size of several decimeters * several decimeters.Therefore, in that (specific inductive capacity 8.85pF/m * conducting element is towards the estimated area 0.1 * 0.1m of power lead ²Between/conducting element and the power lead apart from 0.1m) the basis on, electrostatic capacitance C is approximately 1pF.

The input impedance Zin that supposes to be connected to the impedance transformer 154 that detects conducting element 152 is 50,000 Ω or bigger.According to equation (3) cutoff frequency is about 3MHz.For this reason, Partial Discharge Detection not affected by noise is possible in corresponding to the detection band of several MHz or bigger frequency band, and the transducer noise reduces in described frequency band, as shown in figure 38.

Yet because a pulse of shelf depreciation can have several MHz that wherein produce noise or lower frequency component, therefore transducer can not reproduce the partial discharge pulse that flows to power lead 102 fully in some cases.

When cutoff frequency (cutoff frequency II) when being set to the low-frequency band that wherein has noise, as shown in figure 38, can be detected accurate shelf depreciation waveform.When input impedance Zin of the impedance transformer 155 that is connected to other detection conducting elements 153 were 500,000 Ω, cutoff frequency was 300kHz, and wherein said other detect conducting elements and power lead or neutral point lead-in wire 102 and have the electrostatic coupling of about 1pF.Impedance transformer 155 can accurately be exported whole shelf depreciation waveform.

In method shown in Figure 40, view window 142 can be bigger, perhaps detect in some cases conducting element 152 and 153 and power lead 102 between distance can be shorter.Suppose that electrostatic coupling is up to 10pF.The cutoff frequency of self-impedance transducer 154 output signal is made as about 3MHz for future, and the input impedance of impedance transformer 154 is made as 5,000 Ω or bigger.The cutoff frequency of self-impedance transducer 155 output signal is made as 300kHz or bigger for future, the input impedance of impedance transformer 155 can be made as 50,000 Ω or bigger.

As transmission line 167 and 168 common use characteristic impedances is the concentric cable of 50 Ω or 75 Ω.For impedance matching, the output impedance of impedance transformer 154 and 155 is made as 50 Ω or 75 Ω.

As mentioned above, in the 11st embodiment of the present invention, local discharge detection device comprises: two are detected conducting element 152 and 153, they have 10pF or lower electrostatic coupling with the power lead or the neutral point lead-in wire of the stator winding that is connected to electric rotating machine, and do not contact with power lead or neutral point lead-in wire; Impedance transformer 154 with output impedance value of 5,000 Ω or bigger input impedance value and 50 Ω or 75 Ω; And have 50,000 Ω or bigger input impedance value (being that the input impedance value is greater than impedance transformer 154) and output impedance value is the impedance transformer 155 of 50 Ω or 75 Ω.Detect the input end that conducting element 152 is electrically connected to impedance transformer 154.Other detect conducting element 153 and are electrically connected to impedance transformer 155.To detect constantly from the peak value of the pulse signal of the output of the output terminal of impedance transformer 155 and impedance transformer 154, produced simultaneously pulse signal be defined as local discharge signal.This makes it possible to carry out Partial Discharge Detection with higher detection sensitivity and degree of accuracy.

Even in this embodiment, as mentioned above, can remove denoising and accurately receive local discharge waveform by providing two capacitors to replace detecting conducting element 152 and 153.

Figure 43 is the diagrammatic sketch that the local discharge detection device of the electric rotating machine of the 17th embodiment according to the present invention is shown.

Referring to Figure 43, the conducting element 103 of electrostatic coupling to power lead or neutral point lead-in wire 102 is set, described power lead or neutral point lead-in wire are connected to the stator winding 101 of electric rotating machine.As shown in figure 28, the input end 106 of impedance transformer 105 is electrically connected to conducting element 103 via lead-in wire 104.Signal processor 160 receives local discharge pulse signal from the output terminal 109 of transmission line 108, and described transmission line 108 is connected to the output terminal 107 of impedance transformer 105 so that matched impedance.

In addition, the coil 157 of magnetic coupling to power lead or neutral point lead-in wire 102 is set.The current detector 158 of output voltage, for example resistor is connected to coil 157.The output terminal of current detector 158 is connected to the input end 159 of signal processor 160 by transmission line.

As shown in figure 44, signal processor 160 has following function: the polarity of the pulse signal peak value (1) that obtains according to the output terminal 107 from the impedance transformer 105 that is connected to conducting element 103 and the product of the polarity of the pulse signal peak value (2) of induction the current detector 158 that is connected to coil 157 are just or negative, distinguish from electric rotating machine signal of propagating and the signal of propagating from opposition side.

Figure 45 A illustrates the pulse voltage waveform 161 that flows to outside local discharge signal from the stator winding of electric rotating machine by power lead shown in Figure 43 102, pulse voltage waveform (P1) 162 at output terminal 107 places of impedance transformer 105, and the pulse voltage waveform (P2) 163 of induction in the current detector 158 of coil 157.

The waveform 163 of induction has by the waveform 161 to power lead 102 and carries out the shape that differential obtains in coil 157.The polarity of peak value of pulse equals the polarity of first ripple.Coil 157 is arranged on such direction, makes that peak value of pulse has positive polarity when positive pulse signal is outside from the electric rotating machine flow direction.

Figure 45 B illustrates from the outside pulse voltage waveform 164 of local discharge signal that flows to the stator winding of electric rotating machine by power lead shown in Figure 43 102, pulse voltage waveform (P1) 165 at output terminal 107 places of impedance transformer 105, and the pulse voltage waveform (P2) 166 of induction in the current detector 158 of coil 157.

Shown in Figure 45 A and 45B, the polarity of the voltage of responding in coil is reversed according to the flow direction of local discharge signal.

When undersuing flows to power lead, the polarity of the signal of in coil, responding to opposite with when positive pulse signal flows to power lead.That is to say, shown in Figure 44,45A and 45B, the product of the pulse voltage waveform (P2) 163 of induction or 166 polarity is timing in the polarity of the pulse voltage waveform (P1) 162 at output terminal 107 places of impedance transformer 105 or 165 and current detector 158 at coil 157, the local discharge signal that flows to power lead can be estimated flow to from electric rotating machine outside.Be confirmed as noise from the signal of outer flow to electric rotating machine inside.Therefore, utilize method shown in Figure 44 to detect and remove external noise simultaneously.

As mentioned above, in the 12nd embodiment of the present invention, the coil of at least one electrostatic coupling to the conducting element of the power lead that is connected to stator winding 101 or neutral point lead-in wire 102 and at least one magnetic coupling to power lead or neutral point lead-in wire is set.According to the product from the polarity of the output signal peak value of the impedance transformer that is connected to conducting element and the polarity of the output signal peak value of responding in coil is just or negative, the signal that will propagate from electric rotating machine and come from the signal distinguishing of electric rotating machine external communication.Needn't change the inside of electric rotating machine.Can only go between metal frame on every side and relatively easily non-contacting sensor is installed to high voltage component by power lead or the neutral point that changes electric rotating machine.In addition, can accurately detect shelf depreciation.

In the 12nd embodiment, can provide capacitor to replace conducting element 103.Can provide resistor to replace impedance transformer 105.

Figure 46 is the diagrammatic sketch that the local discharge detection device of the electric rotating machine of the 13rd embodiment according to the present invention is shown.

Referring to Figure 46, will be kept in the slit that is formed on (not shown) in the stator core corresponding to the stator winding 101 of the phase in the three-phase (Figure 46 shows a phase) of electric rotating machine, described stator core is installed to the inside surface of stator frame 100.Power lead 102 is connected to the stator winding 101 of each phase.Perhaps, neutral point lead-in wire 102 can be connected to the neutral point of threephase stator winding.The supporting member (not shown) supports contactless conducting element 103, and this element is made by copper or aluminium and electrostatic coupling goes between 102 to power lead or neutral point.

Electrical equipment 169 with electrostatic capacitance Co is connected to element 103, and the input end 106 of impedance transformer 105 104 is electrically connected to conducting element 103 via lead-in wire, in described impedance transformer 105 at least input impedance Zin greater than output impedance Zout.By with detection signal from transmission line 108 (characteristic impedance Z ₀) output terminal 109 be input to signal processor 110, detect partial discharge pulse's signal.Output terminal 109 is connected to the output terminal 107 of impedance transformer 105, so that matched impedance.

108 common use characteristic impedances are the concentric cable of 50 Ω or 75 Ω as transmission line.Therefore, Zout is generally 50 Ω or 75 Ω.

Next will the function of the local discharge detection device of electric rotating machine with above-mentioned setting be described.

Figure 47 illustrates the equivalent electrical circuit that power lead from Figure 46 or neutral point lead-in wire 102 are observed.Power lead or neutral point lead-in wire 102 is connected with a parallel circuit with electrostatic capacitance C, this parallel circuit be included in conducting element 103 and electrostatic capacitance Co between 111 and the input impedance Zi that is grounding to the impedance transformer 105 of earth point 111.The go between ratio of AC voltage peak Vi at 102 places of the output Vo of the output terminal 107 of impedance transformer 105 and power lead or neutral point is provided by following formula

$\mathrm{Vo}/\mathrm{Vi}=1/\sqrt{\{{(1+\mathrm{Co}/C)}^2+{[1/\left({2\mathrm{\πfCZ}}_{\mathrm{in}}\right)]}^2\}}---\left(4\right)$

Figure 48 illustrates the frequency characteristic 170[20*Log (Vo/Vin) among Figure 46 and Figure 47], this frequency characteristic is by using input impedance Zin greater than the impedance transformer of Zout and set C=1pF, Co=10pF, Zin=50k Ω and Zout=50k Ω obtain, Figure 48 also shows the frequency characteristic 116 among Figure 30 and Figure 31, and this frequency characteristic is by setting C=1pF and Z ₀=50 Ω and do not use impedance transformer to obtain.

As from Figure 48, can obviously finding out, in as shown in figure 38 several MHz or higher local discharge signal frequency band, with in detection method shown in Figure 30, compare, output gain is bigger in detection method shown in Figure 46, method wherein shown in Figure 30 is not used impedance transformer, and method shown in Figure 46 is used impedance transformer 105 and the electrostatic capacitance Co that is connected to conducting element 103.

Figure 33 illustrates the equivalent electrical circuit that the signal processor 110 from Figure 28 is observed.Equal characteristic impedance Z ₀Resistance value (Z ₀) two ends of 118 termination transmission lines 108, with the signal that prevents from transmission line 108 to propagate in terminal 107 and the reflection of 109 places.

That is to say, as the output impedance Zout of impedance transformer shown in Figure 28 105, the characteristic impedance Z of transmission line 108 ₀, and the input impedance of signal processor 110 equate (Zout=Z ₀) time, can accurately waveform be sent to signal processor 110.

In the above-described embodiments, the conducting element of electrostatic coupling to power lead or neutral point lead-in wire 102 is set under contactless state, described power lead or neutral point lead-in wire 102 are connected to the stator winding of electric rotating machine.Even, also can detect shelf depreciation as mentioned above by providing the capacitor that is connected to power lead or neutral point lead-in wire 102 to replace conducting element.

In local discharge detection device according to the electric rotating machine of the 13rd embodiment, conducting element 103 or be connected to power lead or an end of the capacitor of neutral point lead-in wire 102 is connected to the input end of input impedance greater than the impedance transformer of output impedance, wherein said conducting element electrostatic coupling is under the contactless state to have electrostatic capacitance to power lead or neutral point lead-in wire 102 and with respect to power lead or neutral point lead-in wire 102, described power lead 102 is connected to the stator winding corresponding to the phase in the three-phase of electric rotating machine, and described neutral point lead 102 is connected to the neutral point of threephase stator winding.Can or be connected to the output terminal of impedance transformer from the output terminal of impedance transformer so that the output terminal of the transmission circuit of matched impedance detects partial discharge pulse's signal.Needn't change the inside of electric rotating machine.Can only go between metal frame on every side and relatively easily non-contacting sensor is installed to high voltage component by power lead or the neutral point that changes electric rotating machine.In addition, can detect shelf depreciation with higher detection sensitivity and degree of accuracy.

Industrial applicibility

Installation under the contactless state be can promote according to local discharge detection device of the present invention and detection method, and Partial Discharge Detection and insulation diagnosis accurately carried out, the reliability that helps to formulate the maintenance plan of suitable high voltage rotating machine and improve it.

Claims (20)

1. the local discharge detection device of an electric rotating machine, it is characterized in that comprising: conducting element, its electrostatic coupling is to the neutral point lead-in wire that is connected to the neutral point with the threephase stator winding with the power lead that is connected corresponding to the stator winding mutually of one in the three-phase of electric rotating machine or electrostatic coupling, and do not contact with described power lead or neutral point lead-in wire; Impedance transformer, it has the input end of the output terminal that is electrically connected to described conducting element and has input impedance greater than its output impedance; And signal processing apparatus, be used to handle the detection signal that obtains from the output terminal of described impedance transformer detecting the Partial Discharge Detection pulse signal, and

The electrostatic capacitance of described conducting element and the input impedance of described impedance transformer have formed Hi-pass filter, so that from the output signal of described conducting element, obtain described Partial Discharge Detection pulse signal, and

The output impedance of described impedance transformer is configured to the input impedance matching with described signal processing apparatus.

2. the local discharge detection device of electric rotating machine according to claim 1, it is characterized in that: transmission circuit is connected to the described output terminal of described impedance transformer so that the output impedance of described impedance transformer and the input impedance of described transmission circuit are complementary, and makes described signal processing apparatus receive the detection signal that obtains from the output terminal of described transmission circuit.

3. the local discharge detection device of electric rotating machine according to claim 1, it is characterized in that: described conducting element and described impedance transformer are supported by insulcrete, described insulcrete is releasably attached on the view window in the conduction rack that is arranged on hollow, with described conduction rack be arranged on described power lead or neutral point lead-in wire around.

4. the local discharge detection device of electric rotating machine according to claim 1, it is characterized in that also comprising: corresponding to the coil of described conducting element magnetic coupling to described power lead or neutral point lead-in wire, and described signal processing apparatus is by being just or negative based on the product from the polarity of the output signal peak value of described impedance transformer and the polarity of the output signal peak value of responding in described coil, signal that differentiation is propagated from described electric rotating machine and the signal from described electric rotating machine external communication detect described local discharge signal.

5. the local discharge detection device of an electric rotating machine, it is characterized in that comprising: capacitor, one end are connected to the power lead that is connected corresponding to the stator winding mutually of one in the three-phase of described electric rotating machine or are connected to the neutral point lead-in wire that is connected with the neutral point of threephase stator winding; Impedance transformer, it has the input end of the other end that is connected to described capacitor and has input impedance greater than its output impedance; And signal processing apparatus, be used to handle the detection signal that obtains from the output terminal of described impedance transformer detecting the Partial Discharge Detection pulse signal, and

The electrostatic capacitance of described capacitor and the input impedance of described impedance transformer have formed Hi-pass filter, so that from the output signal of described capacitor, obtain described Partial Discharge Detection pulse signal, and

The output impedance of described impedance transformer is configured to the input impedance matching with described signal processing apparatus.

6. the local discharge detection device of electric rotating machine according to claim 5, it is characterized in that: transmission circuit is connected to the described output terminal of described impedance transformer so that the output impedance of described impedance transformer and the input impedance of described transmission circuit are complementary, and makes described signal processing apparatus receive the detection signal that obtains from the output terminal of described transmission circuit.

7. the local discharge detection device of electric rotating machine according to claim 5, it is characterized in that: described capacitor and described impedance transformer are supported by insulcrete, described insulcrete is releasably attached on the view window in the conduction rack that is arranged on hollow, with described conduction rack be arranged on described power lead or neutral point lead-in wire around.

8. the local discharge detection device of electric rotating machine according to claim 5, it is characterized in that also comprising: corresponding to the coil of described capacitor magnetic coupling to described power lead or neutral point lead-in wire, and described signal processing apparatus is by being just or negative based on the product from the polarity of the output signal peak value of described impedance transformer and the polarity of the output signal peak value of responding in described coil, signal that differentiation is propagated from described electric rotating machine and the signal from described electric rotating machine external communication detect described local discharge signal.

9. the local discharge detection device of an electric rotating machine, it is characterized in that comprising: at least two conducting elements with identical or different electric capacity, described conducting element electrostatic coupling is to corresponding to the stator winding of the phase in the three-phase of electric rotating machine or electrostatic coupling power lead or the neutral point lead-in wire to the neutral point that is connected to the threephase stator winding, and do not contact with described power lead or neutral point lead-in wire; At least two impedance transformers with different input resistance value, each impedance transformer have the input end that is electrically connected to corresponding one other end in the described conducting element, and have the input impedance greater than output impedance; And signal processing apparatus, be used to receive the detection signal that obtains from described impedance transformer, and the pulse signal that the detection of the peak value of the pulse detection signals that will obtain with the impedance transformer with less input impedance value from described impedance transformer obtains from the impedance transformer with big input impedance value constantly simultaneously is defined as local discharge signal.

10. the local discharge detection device of electric rotating machine according to claim 9, it is characterized in that: described conducting element and described impedance transformer are supported by insulcrete, described insulcrete is releasably attached on the view window in the conduction rack that is arranged on hollow, with described conduction rack be arranged on described power lead or neutral point lead-in wire around.

11. the local discharge detection device of electric rotating machine according to claim 9, it is characterized in that also comprising: corresponding to the coil of described conducting element magnetic coupling to described power lead or neutral point lead-in wire, and described signal processing apparatus is by being just or negative based on the product from the polarity of the output signal peak value of described impedance transformer and the polarity of the output signal peak value of responding in described coil, signal that differentiation is propagated from described electric rotating machine and the signal from described electric rotating machine external communication detect described local discharge signal.

12. the local discharge detection device of an electric rotating machine, it is characterized in that comprising: at least two capacitors, it has identical or different electric capacity and is connected to corresponding to the stator winding of the phase in the three-phase of electric rotating machine or is connected to power lead or the neutral point lead-in wire, and described power lead or neutral point lead-in wire are connected to the neutral point of threephase stator winding; At least two impedance transformers with different input resistance value, each impedance transformer have the input end that is electrically connected to corresponding one other end in the described capacitor, and have the input impedance greater than output impedance; And signal processing apparatus, be used to receive the detection signal that obtains from described impedance transformer, and the pulse signal that the detection of the peak value of the pulse detection signals that will obtain with the impedance transformer with less input impedance value from described impedance transformer obtains from the impedance transformer with big input impedance value constantly simultaneously is defined as local discharge signal.

13. the local discharge detection device of electric rotating machine according to claim 12, it is characterized in that: described capacitor and described impedance transformer are supported by insulcrete, described insulcrete is releasably attached on the view window in the conduction rack that is arranged on hollow, with described conduction rack be arranged on described power lead or neutral point lead-in wire around.

14. the local discharge detection device of electric rotating machine according to claim 12, it is characterized in that also comprising: corresponding to the coil of described capacitor magnetic coupling to described power lead or neutral point lead-in wire, and described signal processing apparatus is by being just or negative based on the product from the polarity of the output signal peak value of described impedance transformer and the polarity of the output signal peak value of responding in described coil, signal that differentiation is propagated from described electric rotating machine and the signal from described electric rotating machine external communication detect described local discharge signal.

15. the detection method for local discharge of an electric rotating machine, it is characterized in that comprising: the output terminal of conducting element is electrically connected to input impedance is not less than 500 Ω and output impedance is the input ends of 50 Ω to the impedance transformer of 75 Ω, described conducting element with corresponding to one in the three-phase of described electric rotating machine mutually stator winding or be connected to the power lead of neutral point of stator winding or the electrostatic coupling of neutral point lead-in wire is no more than 10pF, and do not contact with described power lead or neutral point lead-in wire; And detecting local discharge signal by handling the detection signal that obtains from the output terminal of transmission circuit, described transmission circuit has 50 Ω to the characteristic impedance of 75 Ω and be connected to the described output terminal of described impedance transformer so that matched impedance.

16. the detection method for local discharge of an electric rotating machine, described electric rotating machine comprises: two conducting elements, each described conducting element with corresponding to one in the three-phase of described electric rotating machine mutually stator winding or be connected to the power lead of neutral point of stator winding or the electrostatic coupling of neutral point lead-in wire is no more than 10pF, and do not contact with described power lead or neutral point lead-in wire; First impedance transformer has the input impedance value that is not less than 500 Ω and the 50 Ω output impedance value to 75 Ω; And second impedance transformer, having the input impedance value that is not less than 50,000 Ω and 50 Ω output impedance value to 75 Ω, the input impedance value of described second impedance transformer is greater than the input impedance value of described first impedance transformer;

The method is characterized in that: a conducting element is electrically connected to the input end of described first impedance transformer, and another conducting element is connected to the input end of described second impedance transformer; And, will detect the pulse signal of exporting from described second impedance transformer simultaneously constantly with the peak value of the pulse signal of exporting from described first impedance transformer and be defined as local discharge signal.

17. the detection method for local discharge of an electric rotating machine, it is characterized in that comprising: at least one conducting element or capacitor and at least one coil are set, described conducting element or capacitor electrostatic coupling are to going between to the neutral point that is connected with the neutral point of stator winding with power lead that is connected corresponding to the stator winding mutually of one in the three-phase of electric rotating machine or electrostatic coupling, and described at least one coil magnetic coupling is to described power lead or neutral point lead-in wire;

The impedance transformer that the electrostatic capacitance of described conducting element or capacitor is set and is connected to described conducting element or capacitor is to form Hi-pass filter, so that obtain described Partial Discharge Detection pulse signal from the output signal of described conducting element;

The output impedance of described impedance transformer is set to the input impedance matching with signal processing apparatus; And

By being just or negative based on product from the polarity of the output signal peak value of one of the resistor that is connected to described conducting element or described capacitor and described impedance transformer and the polarity of the output signal peak value of in described coil, responding to, signal that differentiation is propagated from described electric rotating machine and the signal from described electric rotating machine external communication detect local discharge signal.

18. the local discharge detection device of an electric rotating machine, it is characterized in that comprising: conducting element, its electrostatic coupling is to corresponding to the stator winding of the phase in the three-phase of described electric rotating machine or electrostatic coupling power lead or the neutral point lead-in wire to the neutral point that is connected to the threephase stator winding, and do not contact with described power lead or neutral point lead-in wire; The parallel circuit that comprises electrical equipment and impedance transformer, described electrical equipment has the electrostatic capacitance of the other end that is electrically connected to described conducting element, and described impedance transformer has the input impedance greater than output impedance; And signal processing apparatus, be used for detecting partial discharge pulse's signal by handling the detection signal that obtains from the output terminal of described impedance transformer.

19. the local discharge detection device of an electric rotating machine, it is characterized in that comprising: be connected to corresponding to the stator winding of the phase in the three-phase of electric rotating machine or be connected to power lead or the capacitor of neutral point lead-in wire, described power lead or neutral point lead-in wire are connected to the neutral point of threephase stator winding; The parallel circuit that comprises electrical equipment and impedance transformer, described electrical equipment has the electrostatic capacitance of the other end that is electrically connected to described capacitor, and described impedance transformer has the input impedance greater than output impedance; And signal processing apparatus, be used for detecting partial discharge pulse's signal by handling the detection signal that obtains from the output terminal of described impedance transformer.

20. the detection method for local discharge of an electric rotating machine, it is characterized in that comprising: in the metal frame of the stator frame that is connected to electric rotating machine, setting is corresponding to the power lead of threephase stator coil and one of them of neutral point lead-in wire that be connected to the neutral point of threephase stator coil, and described power lead or neutral point lead-in wire are propagated the local discharge signal that is produced by the degeneration of the described stator coil in the described stator frame; Two sensors are installed, each described sensor comprises around the tours antenna of described power lead or neutral point lead-in wire, make the separately predetermined distance of described sensor simultaneously, and described sensor is set or connects signal lead, so that make the peak value from the output pulse waveform of the described signal lead that is connected to described sensor have opposite polarity from described sensor; Regulate the length of the described signal lead of described sensor, so that make by the electric impulse signal induction that propagates into described power lead or neutral point lead-in wire along the direction that enters described electric rotating machine and output to the pulse signal that is connected to away from the signal lead terminal of the described sensor of described stator winding, arrive in the identical moment with pulse signal caused by the pulse signal that flows to described power lead or neutral point lead-in wire and that output to the signal lead terminal of the described sensor on the side that is connected to described stator coil; And the pulse waveform sum by obtaining via described two barss lead-in wire, detect the described local discharge signal that produces by the degeneration of described stator coil.

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