JP2018036735A - Sensor system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sensor system which eliminates the necessity of battery replacement in order to solve the problem that a battery needs to be replaced at regular intervals in the case where a battery is used for a power source of a sensor, however, an operator cannot easily approach since high voltage in thousands of volts is applied to a power transformer and a breaker.SOLUTION: A sensor system 100 comprises a sensor unit 40 for detecting the state of a measurement target object 10, a transmission unit 50 for transmitting output from the sensor unit 40 to the outside, and a conversion unit 20 for converting a magnetic field from the measurement target object 10 into electric power. The electric power converted by the conversion unit 20 activates at least one of the sensor unit 40 and the transmission unit 50.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a sensor system.

Conventionally, abnormal vibration of a transformer has been detected using a vibration sensor arranged in the transformer (see, for example, Patent Documents 1 and 2). Further, a magnetic flux sensor is provided in the electromagnetic operation mechanism of the electromagnetic operation type circuit breaker, and the open / close pole state of the electromagnetic operation mechanism is monitored from the magnetic flux density measured by the magnetic flux sensor (see, for example, Patent Document 3).
[Prior art documents]
[Patent Literature]
[Patent Document 1] Japanese Patent No. 2617906 [Patent Document 2] Japanese Patent No. 4542957 [Patent Document 3] Japanese Patent No. 4668246

  When a battery is used as a power source for the sensor, it is necessary to periodically replace the battery. However, since a high voltage of several thousand volts is applied to the transformer and the circuit breaker, the operator is not easily accessible. It is therefore desirable to eliminate battery replacement.

  In a first aspect of the invention, a sensor system is provided. The sensor system may include a sensor unit, a transmission unit, and a conversion unit. The sensor unit may detect the state of the measurement target. The transmission unit may transmit the output from the sensor unit to the outside. The conversion unit may convert the magnetic field emitted from the measurement target into electric power. At least one of the sensor unit and the transmission unit may be operated by the electric power converted by the conversion unit.

  The sensor unit may be provided at a position where the magnetic field is weaker than the conversion unit.

  The measurement object may include an electric wire through which a main current flows. The distance from the electric wire to the conversion unit may be shorter than the distance from the electric wire to the sensor unit.

  The sensor system may further include a power storage unit. The power storage unit may store electric power from the conversion unit. The power storage unit may supply the stored power to at least one of the sensor unit and the transmission unit.

  In order for the sensor unit to constantly measure the measurement target, the sensor unit may be constantly supplied with electric power from the power storage unit.

  Electric power may be supplied from the power storage unit to the transmission unit according to the output from the sensor unit to the transmission unit.

  The sensor system may further include a memory unit. The memory unit may store a measurement signal measured by the sensor unit.

  The sensor system may further include a control unit. The control unit may adjust one or more outputs of the sensor unit and the transmission unit according to the strength of the magnetic field emitted from the measurement target.

  The transmission unit may transmit information in which the strength of the magnetic field emitted from the measurement target is associated with the measurement signal of the sensor unit.

  The control unit may control the power supply current to the sensor unit according to the strength of the magnetic field emitted from the measurement target.

  The control unit may control the output of the transmission unit according to the strength of the magnetic field emitted from the measurement target.

  The measurement object may be a transformer. The electric wire through which the main current flows in the transformer may be a coil. The conversion unit may be provided in contact with the coil.

  The measurement object may be a circuit breaker. The electric wire through which the main current flows in the circuit breaker may be a bushing. The conversion unit may be provided in contact with the bushing.

  It should be noted that the above summary of the invention does not enumerate all the necessary features of the present invention. In addition, a sub-combination of these feature groups can also be an invention.

It is a schematic diagram showing measurement system 300 in a 1st embodiment. 1 is a schematic diagram showing a transformer 11 as a measurement object 10. FIG. 1 is a schematic diagram showing a transformer 11 and a sensor system 100. FIG. It is a figure showing sensor system 100 in a 1st embodiment. It is a figure which shows the sensor system 100 in 2nd Embodiment. It is a figure which shows the 1st modification of 2nd Embodiment. It is a figure which shows the 2nd modification of 2nd Embodiment. It is a figure which shows the 3rd modification of 2nd Embodiment. It is a figure which shows the sensor system 100 in 3rd Embodiment. It is a figure which shows the sensor system 100 in 4th Embodiment. It is a figure which shows the sensor system 100 in 5th Embodiment. It is a figure which shows the simulation result which shows the relationship between the main electric current which flows into the electric wire of the transformer 11, and the electric power generation amount of the conversion part. It is a schematic diagram which shows the circuit breaker 15 as the measuring object 10 in 6th Embodiment.

  Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.

  FIG. 1 is a schematic diagram showing a measurement system 300 in the first embodiment. The measurement system 300 of this example includes a sensor system 100 and a processing system 200. The sensor system 100 detects the state of the measurement target 10. The detected state of the measurement object 10 is output from the sensor system 100 to the processing system 200 as a measurement signal. The processing system 200 outputs a measurement signal to the monitoring device 500 via the network 400.

The state of the measuring object 10 includes the vibration, pressure, temperature and humidity of the measuring object 10, sound emitted from the measuring object 10, light and electromagnetic waves, gas components leaking from the measuring object 10, and the voltage, current and It may be one or more of magnetic forces. For example, by detecting the vibration and temperature of the measurement object 10, it is possible to detect deformation and heat generation of the measurement object 10, respectively. Further, a surge voltage generated in the measurement target 10 can be detected by providing the measurement target 10 with a diode that emits light at a predetermined voltage value or higher and detecting light from the diode. Further, it is possible to detect the leakage of the insulating gas (eg, N ₂ and SF ₆₎ by measuring the pressure of the measurement object 10.

  The measurement object 10 may be a device for transporting, converting, controlling and supplying electric power, and a power supply device for electronic equipment. The measurement object 10 may be a device that handles a large current of several hundred A to several thousand A. For example, the measurement object 10 is a transformer and a circuit breaker (Circuit Breaker). In this case, the measuring object 10 has an electric wire through which a main current flows. In addition, the measuring object 10 of this example is a transformer.

  The sensor system 100 may include a conversion unit 20, a power storage unit 30, a sensor unit 40, and a transmission unit 50. The conversion unit 20 has a function of converting a magnetic field emitted from the measurement object 10 into electric power. In order to generate electric power from the magnetic field, the converter 20 may include a coil.

  In this example, the wire through which the main current flows may be a transformer coil. By providing the converter 20 in contact with the coil of the transformer, a leakage magnetic field that does not contribute to the transformer action can penetrate the coil of the converter 20. Thereby, the converter 20 can obtain an induced electromotive force from the leakage magnetic field.

  In another example in which the measurement target 10 is a circuit breaker, a relatively high induction magnetic field is generated around the electric wire through which the main current flows. When the induction magnetic field penetrates the coil of the conversion unit 20, the conversion unit 20 can obtain an induced electromotive force.

  Thus, in the sensor system 100, since the converter 20 generates electric power, a battery as a power source is unnecessary. Therefore, in this example, it is advantageous that the battery need not be replaced. Further, in this example, it is also advantageous that it is not necessary to obtain power from an external fixed power source.

  As described above, the conversion unit 20 of this example functions as a power generation unit of the sensor system 100. The electric power converted by the conversion unit 20 may be stored in the power storage unit 30. By storing power in the power storage unit 30, the power storage unit 30 can supply the stored power to at least one of the sensor unit 40 and the transmission unit 50 even when no induced magnetic field is generated. Thereby, at least one of the sensor unit 40 and the transmission unit 50 can operate.

  The sensor unit 40 may output a measurement signal indicating the state of the measurement target 10 to the transmission unit 50. The measurement signal in this example is the frequency of the measurement object 10 per unit time. The sensor unit 40 may be constantly activated to measure the measurement object 10 constantly, or may be activated intermittently to measure the measurement object 10 intermittently.

  The transmission unit 50 may transmit a measurement signal that is an output from the sensor unit 40 to the reception unit 210 of the processing system 200 outside. The transmission unit 50 in this example is a wireless transmission unit. In the case of wireless, it is advantageous because there is no disconnection in the case of wired.

  The processing system 200 may include a receiving unit 210, a data processing unit 220, and a network device 230. The measurement signal received by the reception unit 210 from the transmission unit 50 may be an analog signal. The analog signal may be supplied to the data processing unit 220 and converted into a digital signal by the data processing unit 220.

  The digital signal may be output to the monitoring apparatus 500 via the network device 230 and the network 400. The monitoring device 500 may display the state (vibration, pressure, temperature, etc.) of the measurement object 10. The monitoring device 500 may have a user interface such as a monitor and hardware such as a CPU. Thereby, the supervisor can know the state of the measuring object 10 in a remote place away from the measuring object 10.

  Note that the sensor system 100 of this example detects the state of the measurement target 10 by the sensor unit 40 in addition to the power generation by the conversion unit 20 and sends the measurement signal obtained by the sensor unit 40 from the transmission unit 50 to the outside. Is intended to send to. Thus, the sensor system 100 that does not require battery replacement is realized.

  FIG. 2 is a schematic diagram showing the transformer 11 as the measurement object 10. The transformer 11 of this example includes a housing 14, a coil 12 and an iron core 13 located inside the housing 14, and a plurality of low-pressure bushings and a plurality of high-pressure bushings located on the housing 14.

  The above-described electric wire corresponds to the coil 12 of the transformer 11. Note that the XYZ axes in FIG. 2 are right-handed orthogonal coordinate axes. In this example, the upward direction means the + Z direction, and the downward direction means the −Z direction. The XYZ axis is only a convenient axis for explaining the relative position. The Z axis is not necessarily a direction parallel to the direction of gravity.

  The transformer 11 of this example includes an iron core 13 having an inner iron type tripod structure and a coil 12 provided on each leg portion of the iron core 13. Each coil 12 (U-phase coil 12-1, V-phase coil 12-2, and W-phase coil 12-3) of this example has a primary coil and a secondary coil concentrically. A main current flows through the primary coil and the secondary coil during voltage transformation.

  The transformer 11 may convert a high voltage (for example, 6 kV) into a low voltage (for example, 210 V). High voltage may be supplied to the primary coil from a high voltage bushing. The converted low voltage may be provided from the secondary coil to the external circuit of the transformer 11 through the low voltage bushing.

  FIG. 3 is a schematic diagram showing the transformer 11 and the sensor system 100. In FIG. 3, the iron core 13 is omitted. The sensor system 100 of this example is a sensor system 100 for the transformer 11. Although FIG. 3 shows an example in which one conversion unit 20 is provided on the coil 12-1, a single conversion unit 20 may be similarly provided in the coils 12-2 and 12-3. In another example, a plurality of conversion units 20 may be provided on the coil 12-1. In yet another example, one or more converters 20 may be provided in contact with the high pressure or low pressure bushing. Moreover, you may combine these examples.

  The sensor unit 40 of this example detects the frequency of the coil 12-1. The sensor unit 40 may be an acceleration sensor element. Although not described in detail, the vibration frequency can be obtained from the acceleration by appropriately processing the output from the acceleration sensor element.

  The sensor unit 40 of this example is provided at a position where the magnetic field is weaker than the conversion unit 20. Thereby, the influence of the magnetic field on the sensor unit 40 can be reduced as compared with the conversion unit 20. In this example, the distance from the coil 12-1 as the electric wire to the conversion unit 20 is made shorter than the distance from the coil 12-1 to the sensor unit 40. That is, in this example, the conversion unit 20 is disposed closer to the coil 12-1 than the sensor unit 40. The entire sensor unit 40 may be covered with a magnetic shield. Thereby, the influence of the magnetic field on the sensor unit 40 may be reduced.

  The sensor unit 40 of this example is provided in direct contact with the casing 14 that is spaced a predetermined distance from the coil 12-1. In this example, since the housing 14 and the coil 12 are integrally connected, both vibrate at the same frequency. Therefore, by providing the sensor unit 40 on the housing 14, it is possible to accurately detect the frequency of the coil 12-1 while keeping the sensor unit 40 away from the coil 12-1.

  In this example, the sensor unit 40 is always supplied with electric power from the power storage unit 30. Thereby, since the sensor part 40 can always measure the frequency of the transformer 11, the abnormality of the transformer 11 is discovered more accurately and quickly than when the sensor part 40 measures the transformer 11 intermittently. be able to.

  The power storage unit 30 and the transmission unit 50 of this example are provided farther from the transformer 11 than the conversion unit 20 and the sensor unit 40. The power storage unit 30 and the transmission unit 50 may be separated from the transformer 11 by 3 m, 5 m, or 10 m. Thereby, the influence of the leakage magnetic field of the transformer 11 with respect to the electrical storage part 30 and the transmission part 50 can further be reduced. In this example, conversion unit 20 and power storage unit 30 may be connected by wiring. The power storage unit 30, the sensor unit 40, and the transmission unit 50 may also be connected to each other by wiring. The wiring may be fixed to the ground or a structure fixed to the ground so as not to be attracted to the electric wire by a magnetic field.

  In addition, arrangement | positioning of the sensor part 40 in another example is shown with a dotted line in FIG. In another example, the sensor unit 40 may be provided on the side of the coil 12-1. For example, the sensor unit 40 is provided in direct contact with the side surface of the coil 12-1. The side of the coil 12 has a weaker magnetic field than the upper end (+ Z direction) and the lower end (−Z direction) of the coil 12. Therefore, it is possible to accurately detect the frequency of the coil 12 while reducing the influence of the magnetic field on the sensor unit 40. In particular, by providing the sensor unit 40 at the center of the coil 12 in the Z direction, the influence of the magnetic field on the sensor unit 40 can be reduced most.

  FIG. 4 is a diagram illustrating the sensor system 100 according to the first embodiment. The conversion unit 20 of this example includes a coil 22 and a rectifier circuit 24. The rectifier circuit 24 of this example includes a diode 25. The power storage unit 30 includes a capacitor 32. One end of the coil 22 is connected to the anode of the diode 25. The other end of the coil 22 is grounded. The cathode of the diode 25 is connected to the high potential side of the capacitor 32. The low voltage side of the capacitor 32 is grounded.

  In the embodiment of the present specification and its modification, the rectifier circuit 24 is included in the conversion unit 20. However, the rectifier circuit 24 only needs to be located closer to the coil 22 than the capacitor 32 of the power storage unit 30. The rectifier circuit 24 may be positioned closer to the coil 22 than the capacitor 32 and may be included in the power storage unit 30.

  The diode 25 may be a normal diode element having a PN junction. The diode 25 may be a JFET (Junction Field Effect Transistor) in which a gate and a drain are short-circuited.

  The coil 22 generates an induced electromotive force from the leakage magnetic field. For example, the coil 22 generates a higher positive voltage on the anode side of the diode 25 than on the ground side. The diode 25 of this example allows a current to flow when a voltage difference of 5 V occurs between the anode and the cathode. Thereby, when the induced electromotive force of the coil 22 is 5 V or more, the capacitor 32 is charged.

  Further, for example, the coil 22 generates a negative voltage lower on the anode side of the diode 25 than on the ground side. The diode 25 of this example does not flow current when the negative voltage is applied. As a result, it is possible to prevent the charge charged in the capacitor 32 from disappearing when a negative bias is applied. The electric power stored in the capacitor 32 is supplied to the sensor unit 40 and the transmission unit 50.

  Since capacitor 32 does not pass a direct current, capacitor 32 of power storage unit 30 in addition to diode 25 may be considered to function as rectifier circuit 24. That is, the capacitor 32 may be regarded as a part of the rectifying element in the rectifying circuit 24 and as a power storage element in the power storage unit 30.

  The sensor unit 40 includes a sensor element 42 and an amplification unit 44. The measurement signal of the measurement object 10 obtained by the sensor element 42 may be an analog signal. The amplifying unit 44 may have a function of amplifying an analog signal. The measurement signal amplified by the amplifying unit 44 may be input to the baseband unit 54 of the signal processing unit 52.

  The transmission unit 50 includes a signal processing unit 52 having a baseband unit 54 and an RF (Radio Frequency) unit 56, and an antenna 58. The baseband unit 54 may convert the analog signal output from the amplification unit 44 into a digital signal. The RF unit 56 may modulate the digital signal to a frequency in the transmission frequency band. The modulated digital signal may be transmitted from the antenna 58 to the receiving unit 210.

  FIG. 5A is a diagram illustrating a sensor system 100 according to the second embodiment. The rectifier circuit 24 of this example further includes a Zener diode 27. The zener diode 27 of this example is connected in antiparallel with the capacitor 32. In this example, the cathode of the Zener diode 27 is connected to the cathode of the diode 25, and the anode of the Zener diode 27 is grounded.

  Zener diode 27 may have a function of maintaining the output voltage of capacitor 32 at a predetermined voltage. In the Zener diode 27, an avalanche current flows when a voltage equal to or higher than a predetermined reverse bias voltage (breakdown voltage) is applied. As a result, the high potential side of the capacitor 32 can be maintained at the same voltage value as the breakdown voltage.

  FIG. 5B is a diagram illustrating a first modification of the second embodiment. The rectifier circuit 24 of this example has a Cockcroft-Walton circuit instead of the diode 25. The Cockcroft-Walton circuit can generate a DC voltage that is 2n times the peak-to-peak voltage generated in the coil 22. Note that n is a natural number.

In the Cockcroft-Walton circuit, two diodes (D ₁ and D ₂ ) are connected in series in the forward direction. A capacitor C ₁ is provided between the cathode of the diode D ₁ and one end of the coil 22. The other end of the diode D ₁ of the anode and the coil 22 are connected. The other end of the coil 22 is grounded. Capacitor C ₂ is provided between the cathode of the anode and the diode D ₂ of the diode D _1.

FIG. 5B shows a structural unit (n = 1) of the Cockcroft-Walton circuit. That is, the constituent unit of the Cockcroft-Walton circuit has two capacitors (C ₁ and C ₂ ) and two diodes (D ₁ and D ₂ ). By connecting a plurality of structural units (n = 1) in series (2 ≦ n), the output voltage of the rectifier circuit 24 can be made higher than when n = 1.

For simplicity of explanation, it is assumed that the coil 22 is an AC voltage power source whose polarity is reversed with respect to time. At the first time (indicated by a circle in 1), the other end (ground side) of the coil 22 has a positive voltage peak value, and one end (opposite side of the ground side) of the coil 22 has a negative voltage peak. Assume that it has a value. In this case, a current flows through the diode D ₁ (the diode D ₂ is no current flow), the capacitor C ₁ is charged. The arrow indicates the direction of current.

In the second time immediately after the first time (indicated by a circle in 2), the other end (ground side) of the coil 22 has a negative voltage peak value, and one end of the coil 22 (what is the ground side) It is assumed that the opposite side) changes to have a positive voltage peak value. In this case, a current flows through the diode _{D 2} (the diode _{D 1} no current flows), the capacitor _{C 2} is charged from the capacitor _{C 1.} Thereby, power storage unit 30 is charged with a voltage boosted from the peak value of the AC voltage power supply. Therefore, the Cockcroft-Walton circuit can be regarded as having a booster circuit function.

  FIG. 5C is a diagram illustrating a second modification of the second embodiment. The sensor system 100 of this example includes a voltage limiter circuit 60 instead of the Zener diode 27. Similarly to the power storage unit 30 and the transmission unit 50, the voltage limiter circuit 60 may be provided apart from the measurement target 10 in order to minimize the influence of the leakage magnetic field.

The voltage limiter circuit 60 has a function of maintaining the high voltage side of the capacitor 32 in a predetermined voltage value range. The voltage limiter circuit 60 of this example includes a first diode 62 connected in antiparallel to the capacitor 32 of the power storage unit 30, a second diode 64 connected in parallel to the capacitor 32, the anode of the first diode 62, and the first diode 62. The reference voltage V _ref is connected to the cathode of the two diodes 64.

In the first diode 62, when the anode becomes higher than the cathode by the first forward voltage _Vf1 , a current flows from the anode to the cathode, and the anode-cathode becomes less than the first forward voltage _Vf1 . Therefore, the voltage limiter circuit 60 maintains the high potential side of the capacitor 32 (the cathode of the first diode 62) below V _ref −V _f1 .

On the other hand, in the second diode 64, when the anode is higher than the cathode by the second forward voltage _Vf2 , a current flows from the anode to the cathode, and the anode-cathode is less than the second forward voltage _Vf2 . Become. Therefore, the voltage limiter circuit 60 maintains the high potential side of the capacitor 32 (the anode of the second diode 64) below V _ref + V _f2 . In this way, the voltage limiter circuit 60 maintains the voltage V on the high potential side of the capacitor 32 at V _ref −V _f1 <V <V _ref + V _f2 . In other examples, it goes without saying that the voltage limiter circuit 60 may have a different configuration.

  FIG. 5D is a diagram illustrating a third modification of the second embodiment. The sensor system 100 of this example includes a booster circuit 70. The booster circuit 70 of this example is a chopper type DC-DC converter. The booster circuit 70 of this example is provided between the power storage unit 30, the sensor unit 40, and the transmission unit 50. Like the power storage unit 30 and the transmission unit 50, the booster circuit 70 may be provided away from the measurement target 10 in order to minimize the influence of the leakage magnetic field.

  The booster circuit 70 of this example includes a coil 72 connected in series to the high potential side of the capacitor 32 and a diode 76 having an anode connected to the coil 72. Further, the booster circuit 70 of this example includes a switching element 74 having a drain terminal connected to the anode of the diode 76, and a capacitor 78 having one end connected to the cathode of the diode 76. The switching element 74 and the capacitor 78 are provided in parallel between the high potential side and the ground side. Although the switching element 74 of this example is an N-channel JFET, the switching element 74 may be a P-channel JFET or a MOSFET.

  When the gate of the switching element 74 is turned on when there is a predetermined potential difference between the high potential side and the ground side, a current flows from the coil 72 to the switching element 74. Thereby, electric power is stored in the coil 72. Thereafter, when the gate of the switching element 74 is turned off, the electric power stored in the coil 72 moves to the high potential side of the capacitor 78 via the diode 76. By switching on / off of the gate in the order of MHz, the capacitor 78 can be boosted to a predetermined voltage value.

  In the above example, the Zener diode 27, the Cockcroft-Walton circuit, the voltage limiter circuit 60, and the booster circuit 70 as the rectifier circuit 24 are individually described. However, it goes without saying that these may be used in appropriate combinations.

  FIG. 6 is a diagram illustrating a sensor system 100 according to the third embodiment. Since the main configuration is the same as that of the second embodiment, differences from the second embodiment will be described below. Of course, this example may be combined with the first embodiment, the second embodiment, and the modifications thereof.

  The sensor system 100 of this example includes a control unit 80. The stronger the magnetic field emitted from the measurement object 10, the higher the possibility that the output of the sensor unit 40 and the transmission unit 50 will be buried in noise. Therefore, the control unit 80 of this example adjusts one or more outputs of the sensor unit 40 and the transmission unit 50 according to the strength of the magnetic field output from the measurement target 10.

  Specifically, the stronger the magnetic field emitted from the measurement object 10, the larger the offset on the output of the sensor unit 40 may be. In order to cope with this, the control unit 80 of this example may calculate an offset value increased in proportion to the magnetic field emitted from the measurement target 10. The control unit 80 may output a control signal for removing the offset value from the output of the sensor unit 40 to the sensor unit 40 or the sensor element 42. The sensor unit 40 or the sensor element 42 may correct the output by the control signal. Thereby, the S / N ratio (Signal to Noise ratio) of the output of the sensor unit 40 can be improved.

  Further, the output from the antenna 58 of the transmitter 50 may be buried in noise due to the magnetic field emitted from the measurement object 10. In order to cope with this, the control unit 80 of this example outputs a control signal for increasing the output from the antenna 58 of the transmission unit 50 to the transmission unit 50 or the signal processing unit 52 in proportion to the magnetic field output from the measurement target 10. You can do it. Thereby, the S / N ratio of the output from the transmission unit 50 to the reception unit 210 can be improved.

  The sensor unit 40 of this example includes a magnetic sensor element 48. The magnetic sensor element 48 may directly measure the magnetic field emitted from the measurement object 10. The magnetic sensor element 48 may be a Hall element, a magnetoresistive effect element, or the like. The magnetic sensor element 48 may output information on the magnetic field emitted from the measurement target 10 to the control unit 80.

  As a modification of this example, the magnetic sensor element 48 may transmit information on the magnetic field emitted from the measurement target 10 to the processing system 200 via the transmission unit 50. Accordingly, in the sensor system 100, the outputs of the sensor unit 40 and the transmission unit 50 may be corrected in the processing system 200 without correcting the outputs of the sensor unit 40 and the transmission unit 50.

  FIG. 7 is a diagram illustrating a sensor system 100 according to the fourth embodiment. Since the main configuration is the same as that of the third embodiment, differences from the third embodiment will be described below. It goes without saying that this example may be combined with the first to third embodiments and their modifications.

  In this example, electric power is supplied from the power storage unit 30 to the transmission unit 50 according to the output from the sensor unit 40 to the transmission unit 50. That is, the control unit 80 in this example supplies power from the power storage unit 30 to the transmission unit 50 when the sensor element 42 outputs a measurement signal to the transmission unit 50. The power storage unit 30 in this example supplies power to the sensor unit 40 and the transmission unit 50 individually in accordance with a power control signal from the control unit 80.

  The time when the sensor element 42 outputs a measurement signal to the transmission unit 50 may be a case where a measurement signal having a predetermined value exists in the measurement signal of the sensor unit 40. The predetermined value may mean an abnormal value of the frequency generated from the measurement object 10 (for example, a specific frequency or a specific frequency band). The sensor element 42 may output the measurement signal to the transmission unit 50 when the measurement signal of the sensor unit 40 reaches a predetermined data amount according to the elapsed time. It may be a case where the total time reaches a predetermined time.

  That is, the transmission unit 50 of this example may not always be activated. Normally, the power consumption of the transmission unit 50 is larger than that of the sensor unit 40. Therefore, the power consumption of the sensor system 100 can be efficiently reduced by turning off the transmission unit 50.

  In order to realize the above configuration, the sensor unit 40 of this example includes a memory unit 46. The memory unit 46 stores the measurement signal measured by the sensor unit 40 via the amplification unit 44.

  In addition to the measurement signal acquired by the sensor element 42, the memory unit 46 may store information on the strength of the magnetic field emitted from the measurement target 10 obtained by the magnetic sensor element 48. As a result, information in which the strength of the magnetic field is associated with the measurement signal can be output from the memory unit 46 to the transmission unit 50. Note that the control unit 80 may control the operation of the memory unit 46 by a control signal output to the sensor unit 40.

  FIG. 8 is a diagram illustrating a sensor system 100 according to the fifth embodiment. The control unit 80 of this example controls the power supply current from the power storage unit 30 to the sensor unit 40 by a control signal to the sensor unit 40 according to the strength of the magnetic field emitted from the measurement target 10. Increasing the power supply current to the sensor unit 40 may mean increasing the amount of current supplied to the sensing transistor used in the sensor element 42. Thereby, the relative ratio of the current flowing through the sensing transistor to the dielectric current generated in the sensing circuit due to the magnetic field emitted from the measurement object 10 can be maintained or increased. Thereby, the S / N ratio of the measurement signal output from the sensor element 42 to the amplifier 44 can be maintained or increased.

  Further, the control unit 80 may control the output of the transmission unit 50 by a control signal to the transmission unit 50 according to the strength of the magnetic field emitted from the measurement target 10. For example, the output of the antenna 58 is increased by increasing the output of the RF unit 56 as the magnetic field emitted from the measurement object 10 increases. Thereby, since the S / N ratio of the radio signal from the transmission unit 50 can be maintained or increased, reception errors in the reception unit 210 can be reduced.

  Further, for example, the output of the antenna 58 is reduced by decreasing the output of the RF unit 56 as the magnetic field emitted from the measurement object 10 is weaker. Thereby, when the magnetic field emitted from the measuring object 10 is weak, the power consumption in the transmission unit 50 can be reduced, and the S / N ratio can be maintained or increased.

  FIG. 9 is a diagram illustrating a simulation result showing a relationship between the main current flowing through the electric wire of the transformer 11 and the power generation amount of the conversion unit 20. A horizontal axis shows the main current (A) which flows into an electric wire. The vertical axis represents the power generation amount (mW (milliwatt)) of the converter 20. In this simulation, the triangle in FIG. 9 indicates the case where the outer shape of the coil 12 is 100 mm (millimeter), the square indicates the case where the outer shape of the coil 12 is 200 mm, and the diamond angle is the outer shape of the coil 12 is 280 mm. Show the case. In each example, the coil 12 of the transformer 11 and the conversion unit 20 are separated by 1 m, and the adjacent coils 12 are separated by 0.5 m. In addition, a separation distance means the distance of the coil 12, the conversion part 20, and the nearest part of the coils 12. According to this simulation, when the outer diameter of the coil 12 was 200 mm and the main current was 3000 A, the power generation amount was 577 mW.

  The result of changing the separation distance between the coil 12 and the converter 20 was also simulated. When the outer diameter of the coil 12 was 200 mm and the main current was 600 A, the power generation amount was 180 mW when the coil 12 and the conversion unit 20 were separated by 0.1 m. Further, when the coil 12 and the converter 20 are brought into contact with each other (that is, the separation distance is set to 0 m), the power generation amount is 260 mW.

  According to the estimation of the inventor of the present application, in order to drive the sensor system 100, the power generation amount of the conversion unit 20 may be 90 mW or more. From this simulation, the outer diameter and main current of the coil 12 necessary for driving the sensor system 100 were calculated.

  FIG. 10 is a schematic diagram showing the circuit breaker 15 as the measurement object 10 in the sixth embodiment. The sensor system 100 of this example is a sensor system 100 for the circuit breaker 15. As described above, the sensor system 100 does not include the circuit breaker 15. The sensor system 100 may be the same as the first to fifth embodiments and the modified examples thereof, or may be a combination thereof.

  The circuit breaker 15 of this example mainly includes a bushing 16, a movable mechanism 610, a movable electrode 612, a fixed electrode 614, and a housing 618. Of course, the circuit breaker 15 may have a configuration other than the above. Although the movable electrode 612 and the fixed electrode 614 are normally connected, the movable mechanism 610 moves the movable electrode 612 away from the fixed electrode 614 when cutting off the current (in the direction of the arrow). Thereby, conduction between the movable electrode 612 and the fixed electrode 614 is interrupted.

In this example, the electric wire of the measuring object 10 through which the main current flows is the bushing 16. The bushing 16 of this example includes a conductor 17 through which a main current flows and an insulating portion 18 provided around the conductor 17. The insulating portion 18 of this example includes a ceramic pipe located at the outermost part of the bushing 16 and an insulating gas between the ceramic pipe and the conductor 17. The insulating gas may be N ₂ gas or SF ₆ gas.

  The conversion unit 20 of this example is provided in contact with the bushing 16. More specifically, the bushing 16 is disposed on the outermost surface of the ceramic tube. The converter 20 can convert the magnetic field emitted from the conductor 17 of the bushing 16 into electric power.

  The sensor unit 40 detects the state of the circuit breaker 15. Also in this example, the sensor unit 40 is an acceleration sensor. Therefore, the state of the circuit breaker 15 detected by the sensor unit 40 is the vibration of the circuit breaker 15. The sensor unit 40 can acquire the frequency of the circuit breaker 15 as a measurement signal. For example, the control unit 80 monitors the abnormal vibration of the circuit breaker 15 by turning on the sensor unit 40 and the transmission unit 50 in response to a sudden event such as a lightning strike.

  The sensor unit 40 may be provided in the housing 618 of the circuit breaker 15. The sensor part 40 should just be provided in the vicinity of the circuit breaker 15 so that the frequency of the circuit breaker 15 can fully be detected. Therefore, the sensor unit 40 may be provided at a position farther from the bushing 16 than the conversion unit 20. Also in this example, the sensor unit 40 may be provided at a position where the magnetic field is weaker than the conversion unit 20. Further, the entire sensor unit 40 may be covered with a magnetic shield.

  Also in this example, since the converter 20 generates electric power, a battery is not necessary as a power source. Therefore, in this example, it is not necessary to replace the battery. Further, it is not necessary to obtain power from an external fixed power source in order to drive the sensor system 100.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above embodiment. It is apparent from the description of the scope of claims that embodiments with such changes or improvements can be included in the technical scope of the present invention.

  The order of execution of each process such as operations, procedures, steps, and stages in the apparatus, system, program, and method shown in the claims, the description, and the drawings is particularly “before” or “prior to”. It should be noted that the output can be realized in any order unless the output of the previous process is used in the subsequent process. Even if the operation flow in the claims, the description, and the drawings is described using “first”, “next”, etc. for convenience, it means that it is essential to carry out in this order. It is not a thing.

  10 .... Measurement target, 11 .... Transformer, 12 .... Coil, 13 .... Iron core, 14 .... Housing, 15 .... Breaker, 16 .... Bushing, 17 .... Conductor, ...... Insulation part , 20, conversion unit, 22, coil, 24, rectifier circuit, 25, diode, 27, Zener diode, 30, storage unit, 32, capacitor, 40, sensor unit, 42, sensor Element 44... Amplifier section 46.. Memory section 48.. Magnetic sensor element 50.. Transmitter section 52.. Signal processing section 54.. Baseband section 56.. RF section 58. Antenna, 60, Voltage limiter circuit, 62, First diode, 64, Second diode, 70, Boost circuit, 72, Coil, 74, Switching element, 76, Diode, 78, Capacitor 80 ... Control unit, 100 ... Sensor system 200 ... Processing system 210 ... Receiving unit 220 ... Data processing unit 230 ... Network equipment 300 ... Measurement system 400 ... Network 500 ... Monitoring device 610 ... Movable mechanism 612 ··· Movable electrode, 614 ·· Fixed electrode, 618 · · Case

Claims (13)

A sensor unit for detecting the state of the measurement object;
A transmission unit for transmitting the output from the sensor unit to the outside;
A conversion unit that converts the magnetic field emitted from the measurement object into electric power,
A sensor system in which at least one of the sensor unit and the transmission unit is operated by the electric power converted by the conversion unit. The sensor system according to claim 1, wherein the sensor unit is provided at a position where the magnetic field is weaker than the conversion unit. The measurement object has an electric wire through which a main current flows,
The distance from the said electric wire to the said conversion part is a sensor system of Claim 1 or 2 shorter than the distance from the said electric wire to the said sensor part. A power storage unit that stores electric power from the conversion unit;
The sensor system according to any one of claims 1 to 3, wherein the power storage unit supplies the stored power to at least one of the sensor unit and the transmission unit. The sensor system according to claim 4, wherein the sensor unit is constantly supplied with electric power from the power storage unit so that the sensor unit always measures the measurement target. The sensor system according to claim 4 or 5, wherein electric power is supplied from the power storage unit to the transmission unit in accordance with an output from the sensor unit to the transmission unit. The sensor system according to claim 6, further comprising a memory unit that stores a measurement signal measured by the sensor unit. The sensor system according to any one of claims 1 to 7, further comprising a control unit that adjusts one or more outputs of the sensor unit and the transmission unit according to a strength of a magnetic field emitted from the measurement target. The sensor system according to claim 8, wherein the transmission unit transmits information in which a strength of a magnetic field emitted from the measurement target is associated with a measurement signal of the sensor unit. The sensor system according to claim 8 or 9, wherein the control unit controls a power supply current to the sensor unit according to a strength of a magnetic field emitted from the measurement target. The sensor system according to any one of claims 8 to 10, wherein the control unit controls an output of the transmission unit according to a strength of a magnetic field emitted from the measurement target. The measurement object is a transformer,
The wire through which the main current flows in the transformer is a coil,
The sensor system according to claim 1, wherein the conversion unit is provided in contact with the coil. The measurement object is a circuit breaker,
The electric wire through which the main current flows in the circuit breaker is a bushing,
The sensor system according to claim 1, wherein the conversion unit is provided in contact with the bushing.

Images