Partial discharge sensor

Abstract

To provide a compact partial discharge sensor that can be practically installed permanently.SOLUTION: A partial discharge sensor 2 according to the present disclosure is for monitoring partial discharge in a high-voltage electrical device 1, and comprises an antenna 50 for receiving electromagnetic waves emitted by partial discharge, a detector 54 for detecting the electromagnetic waves received by the antenna 50, and a self-generating device 4 for generating power using energy surrounding the high-voltage electrical device 1 and supplying the generated power to the detector.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a partial discharge sensor.

Background Art

[0002] International Publication No. 2015 / 190260 (Patent Document 1) discloses a partial discharge diagnosis system that detects partial discharges generated inside a high-voltage electrical device and diagnoses the presence or absence of insulation degradation. This partial discharge diagnosis system includes a partial discharge antenna and a partial discharge detection circuit that detects a discharge signal from the partial discharge antenna. The partial discharge detection circuit is equipped with a battery for supplying a circuit drive voltage.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the partial discharge diagnosis system described in Patent Document 1, in order to increase the operating time of the partial discharge detection circuit, a large-capacity battery is required, resulting in an increase in the device size.

[0005] In addition, since the partial discharge detection circuit is usually installed in a high-voltage environment where high-voltage electrical equipment is installed, there is a problem that maintenance such as inspection and replacement of the battery becomes difficult. Therefore, there is a concern that a battery with a limited power life may not be practical as a power source for the partial discharge detection circuit.

[0006] The present disclosure has been made to solve such problems. The first object of the present disclosure is to provide a small-sized partial discharge sensor. The second object of the present disclosure is to provide a partial discharge sensor that can be practically installed permanently.

Means for Solving the Problem

[0007] A partial discharge sensor according to the present disclosure is a partial discharge sensor for monitoring partial discharge in a high-voltage electrical apparatus, and includes an antenna that receives electromagnetic waves radiated by partial discharge, a detector that detects the electromagnetic waves received by the antenna, and a self-power generation device that performs self-power generation using the energy around the high-voltage electrical apparatus and supplies the generated power to the detector.

Advantages of the Invention

[0008] According to the present disclosure, a practical permanent type partial discharge sensor can be provided. Further, according to the present disclosure, a small-sized partial discharge sensor can be provided.

Brief Description of the Drawings

[0009]

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Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the following, the same or corresponding parts in the drawings are denoted by the same reference numerals, and the description thereof will not be repeated in principle.

[0011] Embodiment 1.

[0012] <Configuration of Partial Discharge Sensor>

[0013] FIG. 1 is a diagram showing the overall configuration of a partial discharge sensor according to Embodiment 1. The partial discharge sensor 2 according to Embodiment 1 is a sensor for continuously monitoring the partial discharge of the high-voltage electrical equipment 1. Partial discharge refers to a weak discharge that occurs when there are minute void-like defects on the surface or inside of the insulator of the high-voltage electrical equipment 1 and the electric field concentrates in that part. The high-voltage electrical equipment 1 to be monitored is, for example, a turbine generator, a high-voltage motor, or the like.

[0014] Due to the deterioration of the insulator caused by partial discharge, there is a possibility that the high-voltage electrical equipment 1 may reach insulation abnormality. In order to detect the signs of insulation abnormality at an early stage, the partial discharge sensor 2 is configured to continuously measure partial discharge by detecting the electromagnetic waves in the GHz band radiated by the partial discharge.

[0015] As shown in FIG. 1, the partial discharge sensor 2 includes an antenna 50, signal lines 52 and 56, a detector 54, and a wireless module 58.

[0016] The antenna 50 is attached to the high-voltage electrical equipment 1. When the high-voltage electrical equipment 1 is a turbine generator, the antenna 50 is attached at a location away from the stator winding so as not to affect the main insulation of the stator winding, for example. When the high-voltage electrical equipment 1 is a high-voltage motor, the antenna 50 is attached, for example, outside the inspection window or the cooling ventilation hole of the gap between the rotor and the stator.

[0017] The antenna 50 is, for example, a patch antenna having a planar shape. The patch antenna has a three-layer structure composed of a ground conductor, a dielectric, and a patch conductor. The antenna 50 receives the electromagnetic waves radiated by the partial discharge of the high-voltage electrical equipment 1. The antenna 50 is connected to the detector 54 by the signal line 52.

[0018] The detector 54 detects the electromagnetic waves received by the antenna 50 via the signal line 52. The detector 54 converts the intensity of the detected electromagnetic waves into a digital signal and transmits the generated digital signal to the wireless module 58. The wireless module 58 transmits this digital signal to the diagnostic device 3 by performing wireless communication with the wireless module 302 of the diagnostic device 3.

[0019] The diagnostic device 3 is a device for diagnosing and analyzing partial discharges in the high-voltage electrical equipment 1, and is configured to include a wireless module 302, a communication line 304, an arithmetic processing unit 306, and a display 308. The wireless module 302 transfers the digital signal received from the wireless module 58 of the partial discharge sensor 2 to the arithmetic processing unit 306 via the communication line 304. The arithmetic processing unit 306 monitors the partial discharges in the high-voltage electrical equipment 1 by performing a predetermined analysis process on the digital signal. The arithmetic processing unit 306 displays the diagnostic result on the display 308.

[0020] The partial discharge sensor 2 further includes a self-power generation device as a configuration for generating a driving voltage such as the detector 54. The self-power generation device 4 is configured to perform self-power generation using the energy around the high-voltage electrical equipment 1 and supply the generated power to the detector 54 and the wireless module 58. Examples of self-power generation include photovoltaic power generation, thermoelectric power generation, and magnetic power generation. The self-power generation device 4 includes a power generation module 60, a power supply line 62, and a power storage circuit 64.

[0021] The power generation module 60 is attached to the high-voltage electrical equipment 1. Note that the power generation module 60 may be attached to the surface of the antenna 50. A photovoltaic power generation module that converts an optical signal into an electrical signal, a thermoelectric power generation module that converts a thermal signal into an electrical signal, or a magnetic power generation module that converts a magnetic signal into an electrical signal may be applied to the power generation module 60.

[0022] In Embodiment 1, the power generation module 60 is a magnetic power generation module and is configured to generate power by electromagnetic induction using the vibration generated during the operation of the high-voltage electrical equipment 1. The power generation module 60 generates a positive and negative pulsed voltage in response to the displacement of the magnet due to a slight vibration of the high-voltage electrical equipment 1. The pulsed voltage generated by the power generation module 60 is supplied to the power storage circuit 64 via the power supply line 62. The power generation module 60 will be described in detail later.

[0023] FIG. 2 is a block diagram showing a configuration example of the self-power generation device 4 shown in FIG. 1. As shown in FIG. 2, the power storage circuit 64 includes a rectifier 640 and a power storage element 642.

[0024] The rectifier 640 full-wave rectifies the positive and negative pulsed voltages generated by the power generation module 60. The rectifier 640 may perform half-wave rectification instead of full-wave rectification.

[0025] The power storage element 642 stores the voltage full-wave rectified by the rectifier 640. The power storage element 642 is a rechargeable secondary battery, a capacitor, or the like. Since the waveform of the voltage output by the power generation module 60 is pulsed with prominent peaks due to the large Barkhausen effect, when there is a possibility of exceeding the voltage allowed for power storage in secondary batteries such as lithium-ion batteries, nickel-metal hydride batteries, or nickel-cadmium batteries, a capacitor is used as the power storage element 642. The power stored in the power storage element 642 is used as the power source for the partial discharge sensor 2. That is, the detector 54 and the wireless module 58 operate by receiving power supply from the power storage element 642.

[0026] <Configuration of the power generation module>

[0027] FIG. 3 is a perspective view showing a configuration example of the power generation module 60 shown in FIG. 1. As shown in FIG. 3, the power generation module 60 includes a power generation element 10 and a magnet part 24. The power generation element 10 is attached to the high-voltage electrical device 1 via a pedestal 15. The magnet part 24 is attached to the high-voltage electrical device 1 via a spring 21.

[0028] (Configuration of the power generation element 10)

[0029] FIG. 4 is a diagram showing a configuration example of the power generation element 10. FIG. 4(a) is a perspective view schematically showing the configuration of the power generation element 10, and FIG. 4(b) is a side view of the power generation element 10.

[0030] As shown in Fig. 4(a), the power generation element 10 includes a magnetic core 11, a coil 12, and a magnetic flux concentrator 13. The magnetic core 11 has one or more composite magnetic wires and generates the giant Barkhausen effect. The giant Barkhausen effect refers to a phenomenon in which magnetization abruptly reverses at a certain magnetic field when an external magnetic field changes. The magnetic core 11 has a magnetostrictive effect and expands and contracts due to magnetostriction in response to changes in the applied magnetic field. The coil 12 is wound around the magnetic core 11.

[0031] The magnetic flux concentrator 13 is a soft magnetic material that surrounds the outer periphery of the magnetic core 11. For the soft magnetic material constituting the magnetic flux concentrator 13, preferably, steel materials such as SS400 or S45C, magnetic stainless steel materials such as SUS430 or SUS440, or high permeability materials such as permalloy or permendur are used. However, the soft magnetic material only needs to have a magnetic permeability higher than that of air (a material with a relative magnetic permeability greater than 1). The magnetic flux concentrator 13 includes a first magnetic flux concentrator 13A and a second magnetic flux concentrator 13B disposed at both ends of the magnetic core 11.

[0032] Fig. 5 is a diagram showing another configuration example of the power generation element 10. Fig. 5(a) is a perspective view schematically showing the configuration of the power generation element 10, and Fig. 5(b) is a side view of the power generation element 10.

[0033] As shown in Fig. 5, the power generation element 10 has a bobbin shape and is also called a magnetic bobbin. The coil 12 is wound around a magnetic member 131, which is a constricted portion of the magnetic bobbin. As shown in Fig. 5, the power generation element 10 can be made only of a soft magnetic material such as iron, but by providing the magnetic core 11 that generates the giant Barkhausen effect as shown in Fig. 4, the power generation efficiency can be improved.

[0034] Using Fig. 6, the flow of magnetic flux lines in the power generation element 10 shown in Fig. 4 will be described. Fig. 6 is a side view of the power generation element 10 and the magnet section 24. The power generation element 10 and the magnet section 24 are arranged such that the first magnetic flux concentrator 13A of the power generation element 10 and the magnetized surface 80 (N pole) of the magnet section 24 face each other in the Y direction (corresponding to the horizontal direction of the paper surface).

[0035] FIG. 6(a) is a diagram schematically showing the flow of magnetic field lines 84 in the power generation element 10. The magnetic field lines 84 emerging from the magnetization surface 80 of the magnet portion 24 according to the magnetization direction 82 of the magnet portion 24 enter the first magnetic flux collector 13A, pass through the magnetic core 11, and emerge from the second magnetic flux collector 13B into the air. That is, both the magnetic field lines 84 passing through the first magnetic flux collector 13A and the second magnetic flux collector 13B are directed in the +Y direction. Note that a part of the magnetic field lines 84 directly enters the magnetic core 11.

[0036] FIG. 6(b) is a diagram schematically showing the flow of magnetic field lines 94 in the power generation element 10 when the magnetization direction 92 of the magnet portion 24 is opposite to that in FIG. 6(a). In FIG. 6(b), in contrast to FIG. 6(a), the first magnetic flux collector 13A faces the magnetization surface 90 (S pole) of the magnet portion 24. Therefore, the magnetic field lines 94 pass from the second magnetic flux collector 13B through the magnetic core 11, pass through the first magnetic flux collector 13A, and head towards the magnetization surface 90 (S pole). That is, both the magnetic field lines 94 passing through the first magnetic flux collector 13A and the second magnetic flux collector 13B are directed in the -Y direction. Note that a part of the magnetic field lines 94 directly enters the magnetic core 11.

[0037] As shown in FIGS. 6(a) and 6(b), since the magnetization surfaces 80, 90 of the magnet portion 24 face the first magnetic flux collector 13A of the power generation element 10, and the magnetic flux collecting surfaces of the magnetic flux collectors 13A, 13B are orthogonal to the longitudinal direction of the power generation element 10, the magnetic field lines 84 emerging from the magnetization surface 80 of the magnet portion 24 can enter the first magnetic flux collector 13A straight and pass straight through the magnetic core 11 and emerge from the second magnetic flux collector 13B. Similarly, the magnetic field lines 94 entering the second magnetic flux collector 13B can pass straight through the magnetic core 11 and enter the magnetization surface 90 of the magnet portion 24 straight from the first magnetic flux collector 13A. As a result, the loss of the magnetic field lines 84, 94 entering and leaving the magnet portion 24 is extremely small, so that electromagnetic induction power generation with excellent efficiency can be obtained.

[0038] (Configuration of the magnet portion 24)

[0039] Returning to Fig. 3, the magnet section 24 is composed of a first magnet 25, a second magnet 26, and a weight 27. The weight 27 is installed on the opposite side of the power generation element 10 with respect to the central axis of the vibration of the spring 21. The spring 21 may be any spring such as a leaf spring in addition to a coil spring. Or, it may be a mechanism capable of amplifying vibration by resonance like a spring.

[0040] The spring constant of the spring 21 and the weight of the magnet section 24 are designed to resonate with the spring 21 with respect to the vibration frequency of the high-voltage electrical device 1. Thereby, the minute vibration of the high-voltage electrical device 1 is amplified by the spring 21. Since the displacement amount generated in the magnet section 24 due to the amplification becomes larger than the displacement amount generated in the power generation element 10, a relative displacement occurs between the magnet section 24 and the power generation element 10. And due to this relative displacement, a voltage is generated in the coil 12 of the power generation element 10.

[0041] Also, due to the weight 27, the center of gravity of the magnet section 24 is located on the weight 27 side with respect to the central axis of the vibration of the spring 21. Therefore, the magnet section 24 can vibrate not in a simple vibration but in a pendulum-like motion. By this pendulum-like motion, the displacement amount of the position of each of the first magnet 25 and the second magnet 26 constituting the magnet section 24 with respect to the power generation element 10 can be amplified as compared with the case of simple vibration.

[0042] As shown in Fig. 3, the first magnet 25 and the second magnet 26 are provided so as to face the magnetic collector 13 of the power generation element 10. The first magnet 25 and the second magnet 26 are arranged such that the magnetic forces are substantially equal and the polarities (directions of magnetization) of each other are opposite with respect to the power generation element 10, as indicated by the magnetic moments 25M and 26M. The magnetized surfaces of the first magnet 25 and the second magnet 26 on the side not facing the magnetic collector 13 are attached to the magnetic yoke 29.

[0043] That is, the first magnet 25 and the second magnet 26 are magnetized such that their polarities are opposite to each other and the magnetic force lines generated from each of the first magnet 25 and the second magnet 26 penetrate the power generation element 10 along the magnetic core 11. And they are fixed to the magnetic yoke 29 such that the magnetized surfaces of each of the first magnet 25 and the second magnet 26 are aligned corresponding to the direction of relative displacement.

[0044] The magnetic yoke 29 is made of a soft magnetic material such as iron. In Embodiment 1, since the magnetic yoke 29 is magnetized by the magnetic forces of the first magnet 25 and the second magnet 26, the magnetic force acting on the power generation element 10 can be increased as a result. Note that the magnetic yoke 29 may be integrated with the weight 27.

[0045] The first magnet 25, the second magnet 26, the weight 27, and the magnetic yoke 29 are covered by a housing 30. The housing 30 is made of a non-magnetic material such as copper, aluminum, or synthetic resin. The first end of the spring 21 is fixed to the bottom of the housing 30. The second end of the spring 21 is fixed to the high-voltage electrical device 1.

[0046] <Operation of the power generation module>

[0047] Next, the operation of the power generation module 60 will be described.

[0048] FIG. 7 is a diagram showing the positional relationship between the displacement direction D1 of the first magnet 25 and the second magnet 26 and the magnetic flux concentrator 13 of the power generation element 10. In FIG. 7, the displacement direction D1 indicates the direction of change in the relative position of the resonated magnet portion 24 with respect to the power generation element 10.

[0049] The magnetized surfaces of the first magnet 25 and the second magnet 26 face the magnetic flux concentrator 13 with a gap 31 therebetween. As the gap 31 becomes narrower, the magnetic force exerted by the first magnet 25 and the second magnet 26 on the magnetic core 11 increases, and thus the power generation amount increases.

[0050] FIG. 8 is a diagram showing an example of the waveform of the magnetic flux density of the magnet portion 24 when the gap 31 is 0.5 mm, 1 mm, or 2 mm. As shown in FIG. 8, the magnetic flux density is maximum when the gap 31 is 0.5 mm. However, since a magnetic attraction force acts between the first magnet 25 and the second magnet 26 and the magnetic flux concentrator 13, the minimum gap 31 that can be actually assembled is about 1 mm. In Embodiment 1, since the magnet portion 24 performs a pendulum motion, the gap 31 is set so that the pendulum-moved magnet portion 24 does not interfere with the magnetic flux concentrator 13.

[0051] As shown in FIG. 8, the magnetic flux density waveform in the thickness direction of the magnet, that is, in the direction of the magnetic moment 25M or the magnetic moment 26M, has two peaks on the positive side of the magnetic flux density. When the gap 31 is 1 mm, the interval between the peaks is about 6 mm, so the width of the most efficient magnetic flux collector 13 becomes 6 mm. When the gap 31 is 1 mm, in order to obtain more magnetic force, for example, by installing a magnetic flux collector 13 with a width of about 8 mm, it becomes possible to collect more magnetic flux lines 55 to the magnetic core 11. Theoretically, about 90% of the magnetic flux of the magnet part 24 can be induced to the magnetic core 11.

[0052] The width of the magnetic flux collector 13 in the direction of the relative displacement (vertical direction in FIG. 3) with respect to the magnet part 24 is about 60% of the width of each magnetization surface of the first magnet 25 and the second magnet 26 of the magnet part 24 facing the magnetic flux collector 13, with an upper limit of 80%. At least two magnets, the first magnet 25 and the second magnet 26, are required for the magnet part 24. The smaller the installation interval between the first magnet 25 and the second magnet 26, the more power can be generated with a smaller displacement amount of the magnet. When the width of the magnetic flux collector 13 in the direction of the relative displacement is wide, it is necessary to widen the gap 28 between the first magnet 25 and the second magnet 26. Therefore, exceeding the above-mentioned most efficient width (6 mm) is disadvantageous in terms of the magnet interval. Therefore, from the viewpoint of the balance between the magnetic force and the magnet interval, the width of the magnetic flux collector 13 is preferably 60% of the width of the magnet, with an upper limit of 80%.

[0053] The gap 28 between the first magnet 25 and the second magnet 26 is made of a non-magnetic material. The width of the gap 28 in the direction of the relative displacement is preferably not less than the width of the magnetic flux collector 13 in the direction of the relative displacement. The gap 28 may be an air gap or filled with a non-magnetic material such as copper, aluminum, or synthetic resin.

[0054] If the width of the magnetic flux concentrator 13 in the direction of relative displacement is wide, when the magnetic flux concentrator 13 relatively displaces and straddles the first magnet 25 and the second magnet 26, the magnetic flux concentrator 13 will collect both the magnetic lines of force of the first magnet 25 and the magnetic lines of force of the second magnet 26. As a result, two magnetic lines of force in opposite directions within the magnetic core 11 will cancel each other out, and the change in magnetic flux within the magnetic core 11 will become sluggish. Therefore, as shown in FIG. 7, by providing a gap 28 equal to or greater than the width of the magnetic flux concentrator 13, the magnetic flux concentrator 13 is suppressed from straddling the first magnet 25 and the second magnet 26, and the change in magnetic flux within the magnetic core 11 can be increased.

[0055] As shown in FIGS. 3 and 7, when the spring 21 is not vibrating, the power generation element 10 faces the magnetization surface of either the first magnet 25 or the second magnet 26 with the magnetic flux concentrator 13. Therefore, by arranging the power generation element 10 in series with the first magnet 25 or the second magnet 26, such as the first magnet 25 and the power generation element 10, or the second magnet 26 and the power generation element 10, the magnetic lines of force 55 generated from one end of the first magnet 25 or the second magnet 26 reach the other end of the first magnet 25 or the second magnet 26 via the magnetic core 11. As a result, the magnetic lines of force 55 generated from the first magnet 25 or the second magnet 26 can be efficiently induced into the magnetic core 11. When the magnetic lines of force 55 generated from the first magnet 25 or the second magnet 26 are efficiently induced into the magnetic core 11, in addition to the pulse voltage due to the large Barkhausen effect, a voltage is generated in the coil 12 by electromagnetic induction.

[0056] Also, when the spring 21 vibrates due to resonance, the magnet corresponding to the magnetic flux concentrator 13 is switched from, for example, the first magnet 25 to the second magnet 26, so the magnetic field applied to the magnetic core 11 is reversed. Due to this reversal of the magnetic field, the large Barkhausen effect in which the magnetization direction inside the magnetic core 11 is reversed appears, electromagnetic induction occurs in the coil 12, and a pulse voltage is generated in the coil 12.

[0057] In Embodiment 1, the magnetic flux concentrator 13 faces the magnetization surface of each of the first magnet 25 and the second magnet 26, so that most of the magnetic field lines 55 generated from the first magnet 25 or the second magnet 26 propagate to the magnetic core 11 via the magnetic flux concentrator 13 facing the magnetization surface. As a result, the magnetic field lines 55 can be efficiently induced to the magnetic core 11 via the magnetic flux concentrator 13. Then, the magnetic field lines 55 generated from the first magnet 25 or the second magnet 26 propagate along the magnetic core 11 so as to penetrate the power generation element 10. When the magnet part 24 moves according to the displacement direction D1 by resonance, the magnet facing the magnetic flux concentrator 13 switches between the first magnet 25 and the second magnet 26, and the direction of the magnetic field lines 55 acting on the magnetic flux concentrator 13 is reversed. Thereby, a voltage due to the giant Barkhausen effect and electromagnetic induction is generated in the coil 12.

[0058] FIG. 9 is a diagram showing an example of the waveform of the voltage generated in the coil 12. FIG. 9(a) shows the waveform 140 of the voltage generated by electromagnetic induction in a coil wound around an iron core having no giant Barkhausen effect and the waveform 141 of the voltage due to only the giant Barkhausen effect. The waveform 140 shows that the pulse width of the voltage is wide and the generated charge amount is large, but the peak voltage is as low as about 5V. On the other hand, the waveform 141 shows that the peak voltage is as high as 15 to 20V, but the pulse width is as narrow as 80 μS or less and the charge amount is small.

[0059] FIG. 9(b) shows the waveform 142 of the voltage generated in the coil 12 of the power generation module 60 according to Embodiment 1. The waveform 142 is equal to the waveform 140 of the voltage due to electromagnetic induction with the waveform 141 of the voltage due to the giant Barkhausen effect superimposed thereon. Therefore, a high voltage of about 20 to 25V can be obtained together with a wide pulse width. In order to efficiently charge a power storage element 642 such as a capacitor, both a potential difference and a charge are required, and the power generation module 60 according to Embodiment 1 is suitable for charging the power storage element 642.

[0060] <Effect>

[0061] As described above, in the self-power generation device 4, as long as the high-voltage electrical equipment 1 is operating, the power generation module 60 can continuously generate electricity by utilizing its vibration. Further, by utilizing the giant Barkhausen effect, the power generation module 60 can always generate a constant voltage regardless of the operating speed of the high-voltage electrical equipment 1 (i.e., the moving speed of the magnet). Therefore, the partial discharge sensor 2 can continuously monitor the partial discharge of the high-voltage electrical equipment 1 using the power generated by the power generation module 60.

[0062] In the prior art of driving the detector 54 using the power of the battery as described above, in order to increase the operating time of the detector 54, a large-capacity battery is required, resulting in a problem of increased device size. Further, since the partial discharge sensor 2 is usually installed in a high-voltage environment where the high-voltage electrical equipment 1 is installed, there is a concern that maintenance such as inspection and replacement of the battery will be difficult. Therefore, there is a problem that a battery with a limited power life is not practical as a power source for the partial discharge sensor 2.

[0063] In contrast, the partial discharge sensor 2 according to Embodiment 1 includes the self-power generation device 4 having the power generation module 60 capable of continuously generating electricity as long as the high-voltage electrical equipment 1 is operating. Therefore, a battery is not required, and the device size can be reduced. Further, since battery maintenance work is not required, a practical permanent type partial discharge sensor can be realized.

[0064] Embodiment 2.

[0065] In and after Embodiment 2, another configuration example of the power generation module 60 used in the partial discharge sensor 2 according to Embodiment 1 will be described. Note that since the configurations other than the power generation module 60 are the same as those in Embodiment 1, detailed descriptions thereof are omitted.

[0066] FIG. 10 is a perspective view showing the configuration of the power generation module according to Embodiment 2. The power generation module 72 according to Embodiment 2 is different from the power generation module 60 shown in FIG. 3 in that the magnet portion 40 does not have the weight 27 and has the holding mechanism 34.

[0067] The magnet portion 40 is the same as the magnet portion 24 shown in FIG. 3 except that it does not have the weight 27. That is, the gap 42 between the first magnet 25 and the second magnet 26 is formed of a non-magnetic material. The width of the gap 42 in the direction of relative displacement is preferably equal to or greater than the width of the flux concentrator 13 in the direction of relative displacement. The gap 42 may be an air gap or may be filled with a non-magnetic material such as copper or aluminum. Further, by providing the gap 42 to be approximately equal to or greater than the width of the flux concentrator 13, the possibility that the flux concentrator 13 straddles the first magnet 25 and the second magnet 26 is suppressed, so that the magnetic flux change inside the magnetic core 11 can be increased.

[0068] The first magnet 25, the second magnet 26, and the magnetic yoke 41 are covered with a housing 43. The first end of the spring 21 is connected to the bottom of the housing 43. The second end of the spring 21 is connected to the holding mechanism 34.

[0069] The holding mechanism 34 is configured to hold the spring 21 at an arbitrary position with respect to the total length of the spring 21. There are holding mechanisms 34 having different lengths in the direction of the arrow 33. By using the holding mechanism 34 having different lengths in the direction of the arrow 33, the length of the portion where the spring 21 vibrates (hereinafter, also referred to as "spring length") can be changed. Even for high-voltage electrical equipment 1 of the same model, there may be individual differences in the vibration frequency. In such a case, by adjusting the spring length by the holding mechanism 34, the spring constant is adjusted to the resonance frequency for each high-voltage electrical equipment 1, so that the power generation module 72 can generate power efficiently.

[0070] In addition, in Embodiment 2, a configuration in which the magnet portion 40 does not have the weight 27 is illustrated, but similar to the power generation module 60, it may have the weight 27.

[0071] FIG. 11 is a perspective view showing the configuration of a power generation module according to a modification of Embodiment 2. The power generation module 74 according to the modification of Embodiment 2 is different from the power generation module 72 shown in FIG. 10 in that it has a holding mechanism 35 instead of the holding mechanism 34.

[0072] As shown in FIG. 11, the holding mechanism 35 has a cylindrical shape, and a plurality of screw holes are formed in the vertical direction on its side surface. By locking the bolt 36 in any one of the plurality of screw holes, the holding mechanism 35 is configured to hold at an arbitrary position with respect to the entire length of the spring 21.

[0073] In this modification, by changing the position of the bolt 36 locked to the holding mechanism 35, the spring constant of the spring 21 can be easily and quickly adjusted to the resonance frequency for each high-voltage electrical device 1.

[0074] In the above-described Embodiments 1 and 2, the configuration in which the magnetic flux concentrator 13 is provided in the power generation element 10 has been described, but the present invention is not limited thereto. For example, the power generation element 10 may have a configuration having only the magnetic core 11 and the coil 12 without the magnetic flux concentrator 13. Further, a configuration in which the magnetized surface of the magnet portion 24 and the magnetic flux concentrator 13 do not face each other may also be used. Furthermore, the power generation element 10 may have a configuration having only a bobbin-shaped member made of a soft magnetic material without the magnetic core 11.

[0075] Embodiment 3.

[0076] FIG. 12 is a perspective view showing the configuration of a power generation module according to Embodiment 3. The power generation module 76 according to Embodiment 3 is different from the power generation module 60 shown in FIG. 3 in that it has a magnet portion 400 instead of the magnet portion 24, and a power generation element 110 instead of the power generation element 10.

[0077] The power generation element 110 includes a magnetic core 111 having a first magnetic flux collecting surface 110A and a second magnetic flux collecting surface 110B, a coil 120 wound around the magnetic core 111, and magnetic flux concentrators 112 provided at both ends in the longitudinal direction of the magnetic core 111. The magnet portion 400 includes a first magnet having a first magnetization surface with a first polarity and a second magnet having a second magnetization surface with a second polarity opposite to the first polarity. In FIG. 12, the first magnet and the second magnet are formed by a single bar-shaped magnet 410. The first polarity is the N pole, and the second polarity is the S pole. The first polarity may be the S pole and the second polarity may be the N pole.

[0078] As shown in FIG. 12, the magnet portion 400 has a plurality (e.g., four) of magnets 410. The plurality of magnets 410 are arranged side by side in the D1 direction. The plurality of magnets 410 are arranged such that the polarities of two adjacent magnets 410 in the D1 direction are opposite to each other. The power generation element 110 and the magnet portion 400 are provided so that their relative positions in the D1 direction can be changed. The movement in the D1 direction can be realized, for example, by attaching the magnet portion 400 to the first part of the high-voltage electrical device 1 and attaching the power generation element 110 to the second part of the high-voltage electrical device 1. In this case, the first part and the second part of the high-voltage electrical device 1 are parts that move linearly relative to each other due to the vibration of the high-voltage electrical device 1. In FIG. 12, the magnet portion 400 moves in the D1 direction due to the vibration of the high-voltage electrical device 1, but instead of the magnet portion 400, the power generation element 110 may move in the D1 direction due to the vibration of the high-voltage electrical device 1. When the first part supporting the magnet portion 400 moves in the D1 direction, there exist a first state in which the magnetic flux concentrator 112 of the power generation element 110 faces the first magnetization surface and a second state in which the magnetic flux concentrator 112 of the power generation element 110 faces the second magnetization surface.

[0079] FIG. 13 is a diagram showing the configuration of the power generation module according to Embodiment 3. As shown in FIG. 13, the magnet 410 is magnetized in the longitudinal direction (horizontal direction of the paper). The arrow 430 in the figure indicates the magnetization direction of the magnet 410.

[0080] In Embodiment 3, the magnetization surfaces 410A (N pole) and 410B (S pole) of the magnet 410 do not face the magnetic flux concentrator 112 of the power generation element 110. Utilizing the property that magnetic field lines are incident perpendicularly to the surface of a magnetic material, the magnetic flux concentration surfaces 110A and 110B are perpendicular to the longitudinal direction of the magnetic core 111 (the direction in which magnetic field lines flow). Therefore, the magnetic field lines incident on the magnetic flux concentration surface 110A are directly induced into the magnetic core 111 as they are.

[0081] The magnetic field lines 420 emerging from the magnetization surface 410A (N pole) of the magnet 410 circulate around the magnet 410 and enter the magnetization surface 410B (S pole). At this time, since the power generation element 110 is in the vicinity of the magnet 410, the magnetic field lines circulating around the magnet 410 are concentrated at the magnetic flux concentration surface 110A and follow a path that passes through the magnetic core 111 and reaches the magnetization surface 410B (S pole) of the magnet 410 from the magnetic flux concentration surface 110B. Thus, in Embodiment 3, since only a part of the magnetic field lines emerging from the magnetization surface 410A are collected at the magnetic flux concentration surface 110A and induced to the power generation element 110, the efficiency of electromagnetic induction is lower compared to Embodiment 1. On the other hand, when the power consumption of a load such as the detector 54 is small and the power generation module can supply the power required for the operation of the load, Embodiment 3 enables an increase in the degree of freedom in installing the power generation element 110 with respect to the magnet 410.

[0082] FIG. 14 is a diagram showing the configuration of a power generation module according to a modification of Embodiment 3. The power generation module according to the modification of Embodiment 3 has a different magnetization direction of the magnet 410 from the power generation modules shown in FIGS. 12 and 13.

[0083] As shown in FIG. 14, the magnet 410 is magnetized in the thickness direction. The arrow 432 in FIG. 14 indicates the magnetization direction of the magnet 410. In the example of FIG. 14, the upper left surface of the magnet 410 is the magnetization surface 410A of the N pole, and the upper right surface of the magnet 410 is the magnetization surface 410B of the S pole.

[0084] In this modified example, the magnetized surface 410A (N pole) of the magnet 410 faces the magnetic flux collecting surface 110A which is the side surface of the magnetic flux collector 112, and the magnetized surface 410B (S pole) of the magnet 410 faces the magnetic flux collecting surface 110B which is the side surface of the magnetic flux collector 112. Therefore, the magnetic flux lines 422 emitted from the magnetized surface 410A (N pole) are concentrated at the magnetic flux collecting surface 110A, and take a path that passes through the magnetic core 111 and reaches the magnetized surface 410B of the magnet 410 from the magnetic flux collecting surface 110B.

[0085] In this modified example, since the magnetic flux collecting surface 110A is parallel to the longitudinal direction of the magnetic core 111, it is necessary to guide the magnetic flux lines entering from the magnetic flux collecting surface 110A into the magnetic core 111 so that they are bent by approximately 90 degrees. Therefore, as shown by the dotted line in the figure, there is a possibility that some of the magnetic flux lines do not bend inside the magnetic flux collector 112 and go straight through the magnetic flux collector 112 and leak into the air. As a result, compared with Embodiment 3, the efficiency of electromagnetic induction may decrease.

[0086] Also, when the magnetic core 111 is composed of a bundle of a plurality of composite magnetic wires, the ease of entry of magnetic flux lines may be different between the composite magnetic wires on the side closer to the magnet 410 and the composite magnetic wires on the side farther from the magnet 410. In this case, magnetic flux variation may occur among the plurality of composite magnetic wires, and the efficiency of electromagnetic induction may decrease.

[0087] As in Embodiment 1, by configuring such that the magnetized surface 410A of the magnet 410 faces the magnetic flux collecting surface 110A of the power generation element 110, and the magnetic flux collecting surface 110A is orthogonal to the longitudinal direction of the power generation element 110 (the direction of the magnetic flux lines contributing to power generation in the coil), the magnetic flux lines emitted from the magnetized surface 410A of the magnet 410 enter the magnetic flux collecting surface 110A straight, and then go straight through the magnetic core 111 and exit from the opposite magnetic flux collecting surface 110B. This path is a desirable form that can realize efficient electromagnetic induction power generation with less loss of the magnetic flux lines emitted from the magnet 410.

[0088] Embodiment 4.

[0089] FIG. 15 is a perspective view showing the configuration of a power generation module according to Embodiment 4. The power generation module according to Embodiment 4 differs from the power generation module shown in FIG. 12 in that it has a plurality of power generation elements 110. Each power generation element 110 uses a composite magnetic wire that generates the giant Barkhausen effect as a magnetic core 111, and differs from the power generation element 110 shown in FIG. 12 in that it does not have a magnetic flux concentrator 112.

[0090] In Embodiment 4, when the high-voltage electrical equipment 1 vibrates in the D1 direction, power can be generated by the plurality of power generation elements 110. However, since each power generation element 110 does not have a magnetic flux concentrator 112, the power generation efficiency may be inferior compared to Embodiment 3. However, by making the power consumption of the partial discharge sensor 2 extremely small, it is possible to obtain power that can operate the partial discharge sensor 2 even for power generation by an inefficient electromagnetic induction component. In this case, since the number of components is reduced, the power generation module can be configured at low cost.

[0091] Embodiment 5.

[0092] FIG. 16 is a perspective view showing the configuration of a power generation module according to Embodiment 5. The power generation module according to Embodiment 5 differs from the power generation module shown in FIG. 3 in that it has a magnet section 200 instead of the magnet section 24.

[0093] As shown in FIG. 16, the magnet section 200 has a first magnet 210 and a second magnet 220. The first magnet 210 has a magnetization surface 210A of the first polarity (N pole). The second magnet 220 has a magnetization surface 220A of the second polarity (S pole).

[0094] When the high-voltage electrical equipment 1 that supports the magnet section 200 vibrates (i.e., is displaced) in the D1 direction, there are a first state in which the first magnetic flux concentrator 13A of the power generation element 10 faces the magnetization surface 210A of the first magnet 210, and a second state in which the first magnetic flux concentrator 13A of the power generation element 10 faces the magnetization surface 220A of the second magnet 220.

[0095] The movement in the D1 direction is a linear movement parallel to the magnetization surfaces 210A of the first magnet 210 and 220A of the second magnet 220. The movement in the D1 direction can be realized, for example, by attaching the magnets 210 and 220 to the first part 1A of the high-voltage electrical equipment 1 and attaching the power generation element 10 to the second part 1B of the high-voltage electrical equipment 1. In this case, the first part 1A and the second part 1B of the high-voltage electrical equipment 1 are parts that linearly move relative to each other due to the vibration of the high-voltage electrical equipment 1. Note that in FIG. 16, the magnet portion 200 moves in the D1 direction due to the vibration of the high-voltage electrical equipment 1, but instead of the magnet portion 200, the power generation element 10 may move in the D1 direction due to the vibration of the high-voltage electrical equipment 1.

[0096] FIG. 16 shows a case where the first magnetic flux collecting surface of the power generation element 10 faces the magnetization surface 210A of the first magnet 210. FIG. 17 shows a case where the first magnetic flux collecting surface of the power generation element 10 faces the magnetization surface 220A of the second magnet 220.

[0097] In the case of FIG. 16, similar to FIG. 6(a), the magnetic field lines emerging from the magnetization surface 210A of the first magnet 210 enter the first magnetic flux collector 13A, pass through the magnetic core 11, and emerge from the second magnetic flux collector 13B into the air. In the case of FIG. 17, similar to FIG. 6(b), the magnetic field lines pass from the second magnetic flux collector 13B through the magnetic core 11, via the first magnetic flux collector 13A, and towards the magnetization surface 220A of the second magnet 220.

[0098] Thus, in Embodiment 5, similar to Embodiment 1, the magnetization surface of the magnet faces the magnetic body, and the magnetic flux collecting surface of the magnetic flux collector is orthogonal to the longitudinal direction of the magnetic body (the direction of the magnetic field lines contributing to power generation in the coil). Therefore, similar to Embodiment 1, there is very little loss of the magnetic field lines emerging from the magnet, and efficient electromagnetic induction power generation can be obtained.

[0099] It should be considered that all the disclosed embodiments are illustrative and not restrictive in any way. The scope of the present invention is shown not by the above description but by the claims, and it is intended that all modifications within the meaning and scope equivalent to the claims are included.

Description of Symbols

[0100] 1 High-voltage electrical equipment, 1A First part, 1B Second part, 2 Partial discharge sensor, 3 Diagnostic device, 4 Self-power generation device, 10, 110 Power generation element, 11, 111 Magnetic core, 12, 120 Coil, 13, 13A, 13B, 112 Magnetic collector, 15 Pedestal, 21 Spring, 24, 40, 200, 400 Magnet part, 25, 210 First magnet, 26, 220 Second magnet, 27 Weight, 28, 42 Gap, 29, 41 Magnetic yoke, 30, 43 Housing, 31 Gap, 34, 35 Holding mechanism, 36 Bolt, 50 Antenna, 52, 56 Signal line, 58, 302 Wireless module, 60, 72, 74, 76 Power generation module, 62 Feeding line, 64 Power storage circuit, 131 Magnetic member, 304 Communication line, 306 Arithmetic processing unit, 308 Display, 410 Magnet, 640 Rectifier, 642 Power storage element.

Claims

1. A partial discharge sensor for monitoring partial discharges in high-voltage electrical equipment, comprising: an antenna for receiving electromagnetic waves radiated by the partial discharges; a detector for detecting the electromagnetic waves received by the antenna; a self-power generation device that generates self-power using the energy around the high-voltage electrical equipment and supplies the generated power to the detector.

2. The self-power generation device includes: a power generation module that is attached to the high-voltage electrical equipment and generates power by electromagnetic induction using vibrations generated during operation of the high-voltage electrical equipment; a power storage circuit that stores the power generated by the power generation module. The partial discharge sensor according to claim 1.

3. The power generation module includes: a magnet part having a permanent magnet; a magnetic core that generates a large Barkhausen effect due to a change in magnetic flux, and a power generation element having a coil wound around the magnetic core; the magnet part and the power generation element are attached to the high-voltage electrical equipment such that a relative displacement occurs due to the vibration of the high-voltage electrical equipment; a voltage is generated in the coil of the power generation element due to a change in the magnetic field based on the relative displacement. The partial discharge sensor according to claim 2.

4. In the power generation element, the magnetic core includes one or more composite magnetic wires that produce a large Barkhausen effect. The partial discharge sensor according to claim 3.

5. The power generation element is provided at both ends in the longitudinal direction of the magnetic core and further has a magnetic flux concentrator that is a soft magnetic material; the magnetic core and the magnetic flux concentrator are integrally formed in a bobbin shape. The partial discharge sensor according to claim 3 or 4.

6. The magnet part is attached to the high-voltage electrical equipment via a spring; the spring constant of the spring and the self-weight of the magnet part are determined such that the spring and the magnet part resonate together due to the vibration of the high-voltage electrical equipment. The partial discharge sensor according to claim 3.

7. The magnet part includes a first magnet and a second magnet; the first magnet and the second magnet are magnetized such that their magnetic poles are opposite to each other and the magnetic force lines generated from each penetrate the power generation element along the magnetic core; the magnet part further includes a magnetic yoke that fixes the first magnet and the second magnet such that the magnetization surfaces of the first magnet and the second magnet are arranged corresponding to the direction of the relative displacement. The partial discharge sensor according to claim 5.

8. The width of the magnetic flux concentrator in the direction of the relative displacement is 60% to 80% of the width of the magnetized surface of the magnet portion facing the magnetic flux concentrator in the direction of the relative displacement. The partial discharge sensor according to claim 7.

9. The magnet portion has a non-magnetic gap between the first magnet and the second magnet. The gap is equal to or greater than the width of the magnetic flux concentrator in the direction of the relative displacement. The partial discharge sensor according to claim 7.

10. The magnet portion further includes a weight installed on the side opposite to the power generation element with respect to the central axis of the vibration of the spring. The center of gravity of the magnet portion is located on the side of the weight with respect to the central axis. The partial discharge sensor according to claim 6.

11. The magnet portion further includes a holding mechanism that holds the magnet portion at an arbitrary position with respect to the total length of the spring. The partial discharge sensor according to claim 10.

12. The high-voltage electrical equipment has a first portion and a second portion that moves in the direction of the relative displacement with respect to the first portion due to the vibration of the high-voltage electrical equipment. The magnet portion has a first magnetized surface with a first polarity and a second magnetized surface with a second polarity that is the reverse polarity of the first polarity. One of the magnet portion and the power generation element is installed on the first portion, and the other of the magnet portion and the power generation element is installed on the second portion. The power generation module has a first state in which the power generation element faces the first magnetized surface and a second state in which the power generation element faces the second magnetized surface due to the vibration of the high-voltage electrical equipment. The partial discharge sensor according to claim 3.

13. The power storage circuit includes a rectifier that rectifies the positive and negative pulsed voltages generated in the coil, and a power storage element that stores the voltage rectified by the rectifier. The partial discharge sensor according to claim 3.

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