JP6874301B2 - Sensor system - Google Patents

Description

The present invention relates to a sensor system.

Conventionally, an abnormal vibration of a transformer has been detected by 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 opening / closing 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 literature]
[Patent Document]
[Patent Document 1] Japanese Patent No. 2617906 [Patent Document 2] Japanese Patent No. 4542957 [Patent Document 3] Japanese Patent No. 4682046

When using a battery as the power source for the sensor, it is necessary to replace the battery regularly. However, since high voltages of several thousand volts are applied to transformers and circuit breakers, it is difficult for workers to easily approach them. Therefore, it is desirable to eliminate the need for battery replacement.

In the first aspect of the present 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 operate 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 that of the conversion unit.

The measurement target may have an electric wire through which the 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 the 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, electric power may be constantly supplied to the sensor unit 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 the measurement signal measured by the sensor unit.

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

The transmitting unit may transmit information in which the strength of the magnetic field emitted from the measurement target and the measurement signal of the sensor unit are associated with each other.

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 target 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 target may be a circuit breaker. The 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.

The outline of the above invention does not list all the necessary features of the present invention. Sub-combinations of these feature groups can also be inventions.

It is a schematic diagram which shows the measurement system 300 in 1st Embodiment. It is a schematic diagram which shows the transformer 11 as a measurement object 10. It is a schematic diagram which shows the transformer 11 and the sensor system 100. It is a figure which shows the sensor system 100 in 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 current flowing through the electric wire of a transformer 11 and the power generation amount of a conversion unit 20. It is a schematic diagram which shows the circuit breaker 15 as the measurement 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 inventions that fall within the scope of the claims. Also, not all combinations of features described in the embodiments are essential to the means of solving the invention.

FIG. 1 is a schematic view showing a measurement system 300 according to 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 target 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 states of the measurement target 10 are the vibration, pressure, temperature and humidity of the measurement target 10, the sound, light and electromagnetic waves emitted by the measurement target 10, the components of the gas leaking from the measurement target 10, and the voltage, current and the voltage and current of the measurement target 10. It may be one or more of the magnetic force. For example, by detecting the vibration and temperature of the measurement target 10, the deformation and heat generation of the measurement target 10 can be detected, respectively. Further, the 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 the light from the diode. In addition, leakage of insulating gas (for example, N ₂ and SF ₆ ) can be detected by measuring the pressure of the measurement target 10.

The measurement target 10 may be a device for transporting, converting, controlling and supplying electric power, and a power supply device for electronic devices. The measurement target 10 may be a device that handles a large current of several hundred A to several thousand A. For example, the measurement target 10 is a transformer and a circuit breaker. In this case, the measurement target 10 has an electric wire through which the main current flows. The measurement target 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 the magnetic field emitted from the measurement target 10 into electric power. The conversion unit 20 may have a coil in order to generate electric power from the magnetic field.

In this example, the electric wire through which the main current flows may be a coil of a transformer. By providing the conversion unit 20 in contact with the coil of the transformer, a leakage magnetic field that does not contribute to the transformation action can penetrate the coil of the conversion unit 20. As a result, the conversion unit 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 induced magnetic field is generated around the electric wire through which the main current flows. When the induced magnetic field penetrates the coil of the conversion unit 20, the conversion unit 20 can obtain an induced electromotive force.

As described above, in the sensor system 100, since the conversion unit 20 generates electric power, a battery as a power source is unnecessary. Therefore, in this example, it is advantageous that the battery does not need to be replaced. Further, in this example, it is also advantageous that it is not necessary to obtain electric 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 electric power in the power storage unit 30, the power storage unit 30 can supply the stored electric power to at least one of the sensor unit 40 and the transmission unit 50 even when an induced magnetic field is not generated. As a result, 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 of this example is the frequency of the measurement target 10 in each unit time. The sensor unit 40 may be constantly activated to constantly measure the measurement target 10, or may be intermittently activated to measure the measurement target 10 intermittently.

The transmission unit 50 may transmit the measurement signal output from the sensor unit 40 to the reception unit 210 of the processing system 200 located outside. The transmission unit 50 of this example is a wireless transmission unit. In the case of wireless, it is advantageous because disconnection does not occur 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 receiving unit 210 from the transmitting 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 in the data processing unit 220.

The digital signal may be output to the monitoring device 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 target 10. The monitoring device 500 may have a user interface such as a monitor and hardware such as a CPU. As a result, the observer can know the state of the measurement target 10 at a remote location away from the measurement target 10.

In the sensor system 100 of this example, in addition to the power generation by the conversion unit 20, the sensor unit 40 detects the state of the measurement target 10, and the measurement signal obtained by the sensor unit 40 is externally transmitted from the transmission unit 50. It is intended to be sent to. As a result, the sensor system 100 that does not require battery replacement is realized.

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

The above-mentioned electric wire corresponds to the coil 12 of the transformer 11. The XYZ axes in FIG. 2 are orthogonal coordinate axes of the right-handed system. Further, in this example, the upward direction means the + Z direction, and the downward direction means the −Z direction. The XYZ axes are only convenient axes for explaining relative positions. The Z axis does not necessarily have to be in a direction parallel to the direction of gravity.

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

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

FIG. 3 is a schematic view showing the transformer 11 and the sensor system 100. The iron core 13 is omitted in FIG. 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, one conversion unit 20 may be provided on the coils 12-2 and 12-3 as well. In another example, a plurality of conversion units 20 may be provided on the coil 12-1. In yet another example, one or more conversion units 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 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 that of the conversion unit 20. As a result, 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 an 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 arranged 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 housing 14 separated from the coil 12-1 by a predetermined distance. In this example, since the housing 14 and the coil 12 are integrally connected, they 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, electric power is constantly supplied to the sensor unit 40 from the power storage unit 30. As a result, the sensor unit 40 can constantly measure the frequency of the transformer 11, so that the sensor unit 40 can detect the abnormality of the transformer 11 more accurately and quickly than when the sensor unit 40 measures the transformer 11 intermittently. be able to.

The power storage unit 30 and the transmission unit 50 of this example are provided further separated from the transformer 11 as compared with 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 or more, 5 m or more, or 10 m or more. As a result, the influence of the leakage magnetic field of the transformer 11 on the power storage unit 30 and the transmission unit 50 can be further reduced. In this example, the conversion unit 20 and the 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 that it is not attracted to the wire by a magnetic field.

The arrangement of the sensor unit 40 in another example is shown by 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 portion of the coil 12 has a weaker magnetic field than the upward (+ Z direction) end portion and the downward (−Z direction) end portion of the coil 12. Therefore, the frequency of the coil 12 can be accurately detected 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 minimized.

FIG. 4 is a diagram showing the sensor system 100 according to the first embodiment. The conversion unit 20 of this example has a coil 22 and a rectifier circuit 24. The rectifier circuit 24 of this example includes a diode 25. The power storage unit 30 has 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 may be located closer to the coil 22 than the capacitor 32 of the power storage unit 30. The rectifier circuit 24 may be located closer to the coil 22 than the capacitor 32 and may be included in the power storage unit 30.

The diode 25 may be an ordinary diode element having a PN junction. Further, the diode 25 may be a JFET (JECT Field Effect Transistor) in which the gate and the drain are short-circuited.

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

Further, for example, the coil 22 generates a negative voltage on the anode side of the diode 25, which is lower than that on the ground side. The diode 25 of this example does not pass a current when the negative voltage is applied. This makes it possible to prevent the electric 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 the capacitor 32 does not pass a direct current, the capacitor 32 of the power storage unit 30 may be considered to function as the rectifier circuit 24 in addition to the diode 25. That is, the capacitor 32 may be regarded as a part of the rectifying element in the rectifying circuit 24 and the 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 target 10 obtained by the sensor element 42 may be an analog signal. The amplification unit 44 may have a function of amplifying an analog signal. The measurement signal amplified by the amplification 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 receiver 210.

FIG. 5A is a diagram showing the sensor system 100 in 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 to 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.

The Zener diode 27 may have a function of maintaining the output voltage of the 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 (yield voltage) is applied. As a result, the high potential side of the capacitor 32 can be maintained at a voltage value having the same magnitude as the yield voltage.

FIG. 5B is a diagram showing 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 that occurs 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. _{Further, a capacitor C 1} is provided between the cathode of the diode D ₁ and one end of the coil 22. The anode of the diode D ₁ and the other end of the coil 22 are connected. The other end of the coil 22 is grounded. A capacitor C ₂ is provided between the anode of the diode D _{1 and} the cathode of the diode D _2.

In FIG. 5B, a structural unit (n = 1) of the Cockcroft-Walton circuit is shown. 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 in the case of n = 1.

For the sake of simplicity, it is assumed that the coil 22 is an AC voltage power supply whose positive and negative are reversed with respect to time. At the first time (1 is circled), the other end of the coil 22 (ground side) has a positive voltage peak value, and one end of the coil 22 (opposite side to the ground side) has a negative voltage peak. Suppose it has a value. In this case, a _{current flows through the diode D 1} (no current flows through the diode D ₂ ), and the capacitor C ₁ is charged. The arrow indicates the direction of the current.

In the second time immediately after the first time (indicated by circled 2), the other end (ground side) of the coil 22 has a negative voltage peak value, and one end of the coil 22 (the ground side). The other side) is assumed to have changed to have a positive voltage peak value. In this case, a _{current flows through the diode D 2} (no current flows through the diode D ₁ ), and the capacitor C ₂ is charged from the capacitor C _1. As a result, the power storage unit 30 is charged with a voltage that is higher than the peak value of the AC voltage power supply. Therefore, the Cockcroft-Walton circuit can be considered to have the function of a booster circuit.

FIG. 5C is a diagram showing a second modification of the second embodiment. The sensor system 100 of this example has a voltage limiter circuit 60 instead of the Zener diode 27. Like the power storage unit 30 and the transmission unit 50, the voltage limiter circuit 60 may be provided at a distance 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 within 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, an anode of the first diode 62, and a first diode. _{2 It has a reference voltage V ref} connected to the cathode of the diode 64.

In the first diode 62, when the anode is higher than the cathode by the first forward voltage V _f1 , a current flows from the anode to the cathode, and the voltage between the anode and the cathode becomes less than _{the first forward voltage V f1.} Therefore, the voltage limiter circuit 60 keeps 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 V _f2 , a current flows from the anode to the cathode, and the voltage between the anode and the cathode becomes less than _{the second forward voltage V f2.} Become. Therefore, the voltage limiter circuit 60 keeps 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 be fitted with a different configuration.

FIG. 5D is a diagram showing a third modification of the second embodiment. The sensor system 100 of this example has 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 at a distance from the measurement target 10 in order to minimize the influence of the leakage magnetic field.

The booster circuit 70 of this example has 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 has a switching element 74 in which a drain terminal is connected to the anode of the diode 76, and a capacitor 78 in which one end is connected to the cathode of the diode 76. The switching element 74 and the capacitor 78 are provided in parallel with each other between the high potential side and the ground side. Although the switching element 74 of this example is an N-channel type JFET, the switching element 74 may be a P-channel type 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. As a result, electric power is stored in the coil 72. After that, 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 the gate on / off in the order of MHz, the capacitor 78 can be boosted to a predetermined voltage value.

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

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

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

Specifically, the stronger the magnetic field emitted from the measurement target 10, the larger the offset on the output of the sensor unit 40 may be. In order to deal 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. As a result, the S / N ratio (Signal to Noise ratio) of the output of the sensor unit 40 can be improved.

Further, due to the magnetic field emitted from the measurement target 10, the output from the antenna 58 of the transmission unit 50 may be buried in noise. In order to deal with this, the control unit 80 of this example outputs a control signal that increases 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 emitted from the measurement target 10. You can do it. As a result, the S / N ratio of the output from the transmitting unit 50 to the receiving unit 210 can be improved.

The sensor unit 40 of this example has a magnetic sensor element 48. The magnetic sensor element 48 may directly measure the magnetic field emitted from the measurement target 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. As a result, 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 showing the sensor system 100 according to the fourth embodiment. Since the main configuration is the same as that of the third embodiment, the difference from the third embodiment will be described below. Of course, this example may be combined with the first to third embodiments and modified examples thereof.

In this example, 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 of this example causes the power storage unit 30 to supply electric power to the transmission unit 50 when the sensor element 42 outputs the measurement signal to the transmission unit 50. The power storage unit 30 of this example individually supplies power to the sensor unit 40 and the transmission unit 50 according to the power control signal from the control unit 80.

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

That is, the transmission unit 50 of this example does not have to be started all the time. Since the power consumption of the transmission unit 50 is usually larger than that of the sensor unit 40, 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, the information in which the strength of the magnetic field and the measurement signal are associated can be output from the memory unit 46 to the transmission unit 50. 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 showing the 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 inside the sensor element 42. As a result, 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 target 10 can be maintained or increased. As a result, the S / N ratio of the measurement signal output from the sensor element 42 to the amplification unit 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 stronger the magnetic field emitted from the measurement target 10, the larger the output of the RF unit 56, thereby increasing the output of the antenna 58. As a result, the S / N ratio of the radio signal from the transmitting unit 50 can be maintained or increased, so that the reception error in the receiving unit 210 can be reduced.

Further, for example, the weaker the magnetic field emitted from the measurement target 10, the smaller the output of the RF unit 56, thereby reducing the output of the antenna 58. As a result, when the magnetic field emitted from the measurement target 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 showing a simulation result showing the relationship between the main current flowing through the electric wire of the transformer 11 and the amount of power generated by the conversion unit 20. The horizontal axis represents the main current (A) flowing through the electric wire. The vertical axis shows the amount of power generated by the conversion unit 20 (mW (milliwatt)). In this simulation, the triangle in FIG. 9 shows the case where the outer shape of the coil 12 is 100 mm (millimeters), the square shows the case where the outer shape of the coil 12 is 200 mm, and the diamond angle shows the case where the outer shape of the coil 12 is 280 mm. Show the case. In each example, it is assumed that 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. The separation distance means the distance between the coil 12, the conversion unit 20, and the closest portion between the coils 12. According to this simulation, when the outer diameter of the coil 12 is 200 mm and the main current is 3000 A, the amount of power generation is 577 mW.

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

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

FIG. 10 is a schematic view showing a circuit breaker 15 as a measurement target 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 modifications thereof, or may be a combination thereof.

The circuit breaker 15 of this example mainly has 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. The movable electrode 612 and the fixed electrode 614 are normally connected, but when the current is cut off, the movable mechanism 610 separates the movable electrode 612 from the fixed electrode 614 (in the direction of the arrow). As a result, the continuity between the movable electrode 612 and the fixed electrode 614 is cut off.

In this example, the electric wire of the measurement target 10 through which the main current flows is the bushing 16. The bushing 16 of this example has 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 on the outermost side 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, it is arranged on the outermost surface of the ceramic tube in the bushing 16. The conversion unit 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. In this example as well, 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 turns on the sensor unit 40 and the transmission unit 50 in response to a sudden event such as a lightning strike, and monitors the abnormal vibration of the circuit breaker 15.

The sensor unit 40 may be provided in the housing 618 of the circuit breaker 15. The sensor unit 40 may be provided close to the circuit breaker 15 so that the frequency of the circuit breaker 15 can be sufficiently 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 that of the conversion unit 20. Further, the entire sensor unit 40 may be covered with a magnetic shield.

Also in this example, since the conversion unit 20 generates electric power, no battery is required as a power source. Therefore, in this example, it is not necessary to replace the battery. Further, it is not necessary to obtain electric power from an external fixed power source to drive the sensor system 100.

Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various changes or improvements can be made to the above embodiments. It is clear from the description of the claims that such modified or improved forms may also be included in the technical scope of the present invention.

The order of execution of operations, procedures, steps, steps, etc. in the devices, systems, programs, and methods shown in the claims, specification, and drawings is particularly "before" and "prior to". It should be noted that it can be realized in any order unless the output of the previous process is used in the subsequent process. Even if the scope of claims, the specification, and the operation flow in the drawings are explained using "first", "next", etc. for convenience, it means that it is essential to carry out in this order. It's not a thing.

10 ... Measurement target, 11 ... Transformer, 12 ... Coil, 13 ... Iron core, 14 ... Housing, 15 ... Breaker, 16 ... Bushing, 17 ... Conductor, 18 ... Insulation , 20 ... converter, 22 ... coil, 24 ... rectifier circuit, 25 ... diode, 27 ... Zener diode, 30 ... storage unit, 32 ... capacitor, 40 ... sensor unit, 42 ... sensor Element, 44 ... Amplification section, 46 ... Memory section, 48 ... Magnetic sensor element, 50 ... Transmission section, 52 ... Signal processing section, 54 ... Baseband section, 56 ... RF section, 58 ... Antenna, 60 ... Voltage limiter circuit, 62 ... 1st diode, 64 ... 2nd diode, 70 ... Boost circuit, 72 ... Coil, 74 ... Switching element, 76 ... Diode, 78 ... Capacitor, 80 ... Control unit, 100 ... Sensor system, 200 ... Processing system, 210 ... Receiver 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 ・ ・ Housing

Claims (12)

A sensor unit that detects the state of the measurement target and
A transmitter that transmits the output from the sensor to the outside,
A conversion unit that converts the magnetic field emitted from the measurement target into electric power,
A control unit that adjusts the output of at least one of the sensor unit and the transmission unit according to the strength of the magnetic field emitted from the measurement target is provided.
A sensor system in which at least one of the sensor unit and the transmission unit operates 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 that of the conversion unit. The measurement target has an electric wire through which the main current flows.
The sensor system according to claim 1 or 2, wherein the distance from the electric wire to the conversion unit is shorter than the distance from the electric wire to the sensor unit. Further equipped with a power storage unit for storing 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 electric power to at least one of the sensor unit and the transmission unit. The sensor system according to claim 4, wherein power is constantly supplied to the sensor unit from the power storage unit so that the sensor unit constantly measures the measurement target. The sensor system according to claim 4 or 5, wherein power is supplied from the power storage unit to the transmission unit in response to 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, wherein the transmitting unit transmits information in which the strength of the magnetic field emitted from the measurement target and the measurement signal of the sensor unit are associated with each other. The sensor system according to any one of claims 1 to 8, wherein the control unit controls a power supply current to the sensor unit according to the strength of a magnetic field emitted from the measurement target. The sensor system according to any one of claims 1 to 9, wherein the control unit controls the output of the transmission unit according to the strength of the magnetic field emitted from the measurement target. The measurement target is a transformer.
The electric wire through which the main current flows in the transformer is a coil.
The conversion unit is provided in contact with the coil.
The sensor system according to any one of claims 1 to 10. The measurement target is a circuit breaker.
The electric wire through which the main current flows in the circuit breaker is a bushing.
The conversion unit is provided in contact with the bushing.
The sensor system according to any one of claims 1 to 10.

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