Pressurization detector, pressurization detection method, and pressurization detection system

Abstract

To provide a pressurization detector that can detect application of voltage to a direct current circuit without need of a power source.SOLUTION: A pressurization detector 20 comprises a core wire of a sheath earth 10 disposed in a direct current circuit and an electrode section disposed with a distance from the core wire of the sheath earth 10, and is provided with a capacitor that is charged by a ripple component included in a direct current voltage applied to the direct current circuit, a detection section 11 that detects the ripple component, and a notification section 12 that operates with power supplied from the capacitor and provides notification that the ripple component has been detected by the detection section 11.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a pressure detector, a pressure detection method, and a pressure detection system that detect a state in which a voltage is applied. [Background technology]

[0002] 2. Description of the Related Art Conventionally, a pressure detector has been used to detect a state in which a voltage is applied to a DC circuit to which a DC voltage converted from an AC voltage by a rectifier or the like is applied.

[0003] Patent Document 1 discloses a voltage detector that detects the state in which a voltage is applied based on the signal strength of harmonic frequency components that are generated in response to a reference frequency of an AC current. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-112659 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the electroscope disclosed in Patent Document 1 extracts specific frequency components using a filter and then performs frequency conversion to convert the signal to a preset frequency. Therefore, the electroscope disclosed in Patent Document 1 requires a power source to detect the application of voltage to a DC circuit.

[0006] The present disclosure has been made in view of the above, and aims to provide a pressure detector that can detect the application of voltage to a DC circuit without requiring a power source. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems and achieve the object, the force detector according to the present disclosure is configured with a sheath earth core wire provided in a DC current circuit and an electrode portion provided at a distance from the sheath earth core wire, has a capacitor that is charged by a ripple component contained in a DC voltage applied to the DC current circuit, and is equipped with a detection portion that detects the ripple component. The force detector operates by receiving power from the capacitor, and is equipped with a notification portion that notifies that a ripple component has been detected by the detection portion. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to obtain an effect of providing a pressure detector that can detect the application of voltage to a DC circuit without requiring a power source. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing an installation state of a pressure detector according to the first embodiment; [Figure 2] FIG. 1 is a diagram showing the configuration of a pressure detector according to a first embodiment; [Figure 3] 1 is a cross-sectional view of a detection section of a pressure detector according to a first embodiment; [Figure 4] FIG. 1 is a diagram showing a configuration of a pressure detection system according to a first embodiment. [Figure 5] FIG. 10 is a diagram showing the configuration of a pressure detector according to a second embodiment. [Figure 6] FIG. 10 is a diagram showing the configuration of a pressure detector according to a third embodiment. [Figure 7] FIG. 10 is a diagram showing an example of wiring of a light-emitting diode lamp of a pressure detector according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A pressure detector, a pressure detection method, and a pressure detection system according to embodiments will be described in detail below with reference to the accompanying drawings.

[0011] Embodiment 1 FIG. 1 is a diagram illustrating an installation state of a strain detector according to a first embodiment. The strain detector 20 is installed in a substation 4 that converts high-voltage AC current supplied from a high-voltage distribution system 5 into DC current and supplies the DC current to a railway facility 30. The railway facility 30 includes an electric vehicle 1, an overhead line 2, and rails 3. The substation 4 includes a transformer 7 that steps down the high-voltage AC current input from the high-voltage distribution system 5 via a transmission line 6, a rectifier 8 that converts the AC current output from the transformer 7 into DC current, and a transmission cable 9 that is a DC electric circuit that supplies the DC current output from the rectifier 8 to the overhead line 2. The transmission cable 9 is provided with a sheath earth 10. The strain detector 20 includes a detection unit 11 attached to the sheath earth 10 of the transmission cable 9 and a notification unit 12 connected to the detection unit 11. The detection unit 11 detects a ripple component included in the DC voltage applied to the transmission cable 9 that is a DC electric circuit. Here, the detection unit 11 detects a ripple component contained in a DC voltage applied to the power transmission cable 9 via a sheath earth 10 provided in the power transmission cable 9. The notification unit 12 notifies that the detection unit 11 has detected the ripple component.

[0012] FIG. 2 is a diagram illustrating the configuration of a pressure detector according to the first embodiment. FIG. 3 is a cross-sectional view of a detection unit of the pressure detector according to the first embodiment. The detection unit 11 includes a cylindrical electrode unit 111 and a columnar insulating support unit 112 that maintains a predetermined distance between the sheath earth 10 and the electrode unit 111. The insulating support unit 112 has a hole 113 that penetrates in the axial direction. The sheath earth 10 is placed in the hole 113, so that the electrode unit 111 surrounds the sheath earth 10 from its entire circumference. The insulating support unit 112 installs the electrode unit 111 while maintaining a constant distance from the core wire of the sheath earth 10, thereby forming a capacitor between the core wire of the sheath earth 10 and the electrode unit 111. For example, the electrode unit 111 is installed while maintaining a constant distance from the core wire of the sheath earth 10 by wrapping a strip-shaped electrode around the sheath earth 10 via the insulating support unit 112. The method of winding the electrode is not limited to a particular method, but it is preferable to wind it so that the capacitance of the capacitor formed by the core wire of the sheath earth 10 and the electrode portion 111 becomes large.

[0013] The dielectric material used for the insulating support part 112 is not limited to a specific material as long as it has a relative dielectric constant greater than that of air. When the pressure detector 20 is installed outdoors, it is preferable that the insulating support part 112 be made of a material that is resistant to deterioration even when exposed to sunlight and rainwater.

[0014] The notification unit 12 includes a light emitting diode (LED) lamp 121 electrically connected to the electrode unit 111. The LED lamp 121 receives a supply of electric charge from the electrode unit 111 and emits light.

[0015] The pressure detector 20 is installed inside a weather-resistant case, such as a terminal box that houses the sheath earth 10. Installing the pressure detector 20 inside a weather-resistant case can suppress deterioration due to corrosion of the electrode part 111 and extend its lifespan. When the pressure detector 20 is installed outdoors, the electrode part 111 and the insulating support part 112 may be covered with a cover (not shown) made of a waterproof material such as rubber.

[0016] A current of DC voltage rectified by rectifier 8 flows through transmission cable 9. The current flowing through transmission cable 9 contains ripple components with frequencies that are integer multiples of the fundamental frequency of the AC before rectification, and the voltage value of the DC voltage applied to transmission cable 9 fluctuates periodically.

[0017] The voltage value of the DC voltage applied to the power transmission cable 9 fluctuates periodically, causing the voltage value of the DC current flowing through the sheath earth 10 to fluctuate periodically. As the voltage value of the DC current flowing through the sheath earth 10 fluctuates periodically, charge accumulates in the capacitor formed by the core wire of the sheath earth 10 and the electrode portion 111. When the voltage of the capacitor reaches a certain voltage determined by the electrical resistance of the LED lamp 121, current flows from the capacitor to the notification unit 12, causing the LED lamp 121 to light up for a certain period of time. When the charge accumulated in the capacitor decreases and the capacitor voltage drops, the LED lamp 121 goes out. Therefore, while the DC voltage rectified by the rectifier 8 is flowing through the power transmission cable 9, the notification unit 12 repeatedly turns the LED lamp 121 on and off. In this way, the pressure detector 20 according to the first embodiment performs the steps of charging a capacitor formed by the core wire of the sheath earth 10 provided on the power transmission cable 9 and the electrode portion 111 provided at a distance from the core wire of the sheath earth 10 with the ripple component contained in the DC voltage applied to the power transmission cable 9, detecting the ripple component, and notifying that the ripple component has been detected by receiving power supply from the capacitor.

[0018] Increasing the length of electrode portion 111 increases the capacitance of the capacitor formed by the core wire of sheath earth 10 and electrode portion 111. When the capacitance of the capacitor formed by the core wire of sheath earth 10 and electrode portion 111 increases, it takes longer to accumulate charge in the capacitor up to the voltage required to light LED lamp 121 of notification portion 12, and therefore the blinking cycle of LED lamp 121 becomes longer, but the current flowing from the capacitor to notification portion 12 increases, so the amount of light emitted by LED lamp 121 increases and visibility from a long distance can be improved. On the other hand, shortening the length of electrode portion 111 decreases the capacitance of the capacitor formed by the core wire of sheath earth 10 and electrode portion 111. As the capacitance of the capacitor formed by the core wire of sheath earth 10 and electrode portion 111 decreases, the amount of light emitted by LED lamp 121 decreases, but the time required to accumulate charge in the capacitor up to the voltage required to light up LED lamp 121 of notification portion 12 becomes shorter, thereby shortening the blinking cycle of LED lamp 121 and improving visibility from close range. For this reason, the length of electrode portion 111 should be set based on the distance from which the light emission of LED lamp 121 of notification portion 12 can be seen.

[0019] The strain detector 20 according to the first embodiment detects whether a DC voltage is applied to the power transmission cable 9 by illuminating the LED lamp 121 using electrostatic energy due to the charge accumulated in the capacitor formed by the core wire of the sheath earth 10 and the electrode portion 111, so that no power source is required for operation, and it is possible to achieve miniaturization and cost reduction. By installing the strain detector 20 according to the first embodiment, it becomes possible to visually check the LED lamp 121 whether a DC voltage is applied to the power transmission cable 9, which is a DC current circuit, and therefore it is possible to prevent electric shock accidents in the power transmission cable 9.

[0020] While the configuration in which the LED lamp 121 of the notification unit 12 is illuminated by the power stored in the electrode unit 111 has been given as an example here, it is also possible to install a receiver in a control room (not shown) of the railway facility 30, operate a transmitter instead of the notification unit 12 using the power stored in the electrode unit 111, and receive a signal transmitted from the transmitter by the receiver. Figure 4 is a diagram showing the configuration of a pressure detection system according to the first embodiment. The pressure detection system 80 according to the first embodiment includes a pressure detector 20 that detects a voltage applied to a power transmission cable 9, which is a DC current circuit, and a receiver 31 that receives a voltage detection signal. The pressure detector 20 is composed of a core wire of a sheath earth 10 provided in the power transmission cable 9 and an electrode unit 111 provided at a distance from the core wire of the sheath earth 10. The pressure detector 20 has a capacitor that is charged by ripple components contained in the DC voltage applied to the power transmission cable 9 and includes a detector 11 that detects the ripple components, and a transmitter 122 that operates by receiving power from the capacitor and transmits a detection signal notifying that the ripple components have been detected by the detector 11. A control room (not shown) of the railway facility 30 is provided with a receiver 31 that receives the detection signal transmitted by the transmitter 122 and a display 32 that displays that the receiver 31 has received the detection signal. The transmitter 122 and the receiver 31 communicate with each other in accordance with the Low Power Wide Area Network (LPWAN) standard. For example, the transmitter 122 and the receiver 31 communicate with each other using LoRaWAN (registered trademark), a communication protocol that employs the LoRa (registered trademark) long range (Long Range) modulation method. In this way, it becomes possible to transmit the voltage detection results of the power transmission cable 9 to the railway operator with reduced power consumption.

[0021] Embodiment 2 5 is a diagram showing the configuration of a pressure detector according to embodiment 2. Pressure detector 20 according to embodiment 2 differs from pressure detector 20 according to embodiment 1 in that detection unit 11 is divided into electrode unit 111a and insulating support unit 112a, and electrode unit 111b and insulating support unit 112b, and in that switch 13 is provided for switching between connecting electrode unit 111a and electrode unit 111b to notification unit 12, or connecting only electrode unit 111a to notification unit 12.

[0022] When electrode portion 111a and electrode portion 111b are connected to notification portion 12, the time required to accumulate charge in the capacitor up to the voltage required to light up LED lamp 121 of notification portion 12 is longer than when only electrode portion 111a is connected to notification portion 12, so the blinking period of LED lamp 121 becomes longer, but since the current flowing from the capacitor to notification portion 12 is larger, the amount of light emitted by LED lamp 121 can be increased, improving visibility from a long distance.

[0023] On the other hand, when only electrode portion 111a is connected to notification portion 12, the current flowing from the capacitor to notification portion 12 is smaller than when electrode portion 111a and electrode portion 111b are connected to notification portion 12, and therefore the amount of light emitted by LED lamp 121 is smaller; however, the time required to accumulate charge in the capacitor up to the voltage required to illuminate LED lamp 121 of notification portion 12 is shorter, and therefore the flashing cycle of LED lamp 121 can be shortened, thereby improving visibility from close range.

[0024] In the pressure detector 20 of embodiment 2, when the LED lamp 121 is viewed from a long distance, the electrode portion 111a and the electrode portion 111b are connected to the notification portion 12, and when the LED lamp 121 is viewed from a close distance, only the electrode portion 111a is connected to the notification portion 12. This makes it easy to check whether a DC voltage is being applied to the power transmission cable 9, which is a DC electrical circuit, whether the light emitted by the LED lamp 121 is viewed from a long distance or a close distance.

[0025] Embodiment 3 6 is a diagram showing the configuration of a pressure detector according to embodiment 3. The pressure detector 20 according to embodiment 3 differs from the pressure detector 20 according to embodiment 1 in that it includes three LED lamps 91a, 91b, and 91c.

[0026] FIG. 7 is a diagram showing a wiring example of a light-emitting diode lamp of a pressure detector according to the third embodiment. In the wiring example shown in FIG. 7, a semiconductor integrated circuit (IC) chip 92a and capacitors 93a and 94a are connected in parallel to each other in the LED lamp 91a. An IC chip 92b and capacitors 93b and 94b are connected in parallel to each other in the LED lamp 91b. An IC chip 92c and capacitors 93c and 94c are connected in parallel to each other in the LED lamp 91c. The IC chips 92a, 92b, and 92c are, for example, driver ICs for controlling the lighting and blinking of the LED lamps 91a, 91b, and 91c. The capacitors 93a, 93b, 93c, 94a, 94b, and 94c are LED capacitors that supply power to the LED lamps 91a, 91b, and 91c to cause them to emit light.

[0027] The LED lamps 91a, 91b, and 91c are connected in series. The LED lamp 91a, IC chip 92a, and capacitors 93a and 94a are connected in parallel. The LED lamp 91b, IC chip 92b, and capacitors 93b and 94b are connected in parallel. The LED lamp 91c, IC chip 92c, and capacitors 93c and 94c are connected in parallel.

[0028] In this configuration, the LED lamp 91a is lit for a certain period under the control of the IC chip 92a by supplying electric charge to the capacitors 93a and 94a. The LED lamp 91a is extinguished when the voltage across the capacitors 93a and 94a drops. Similarly, the LED lamp 91b is lit for a certain period under the control of the IC chip 92b by supplying electric charge to the capacitors 93b and 94b, and is extinguished when the voltage across the capacitors 93b and 94b drops. The LED lamp 91c is lit for a certain period under the control of the IC chip 92c by supplying electric charge to the capacitors 93c and 94c, and is extinguished when the voltage across the capacitors 93c and 94c drops.

[0029] Furthermore, when capacitors 93a and 94a discharge, the charge stored in capacitors 93a and 94a is transferred to one of capacitors 93b, 94b, 93c, and 94c located in the other stage. Capacitors 93b, 94b, 93c, and 94c, which are charged by the discharge of capacitors 93a and 94a, respectively, light up LED lamp 91b or LED lamp 91c. The charging of capacitors 93b, 94b, 93c, and 94c due to the discharge of capacitors 93a and 94a causes LED lamps 91a, 91b, and 91c to blink at different timings. This improves visibility. Similarly, when capacitors 93b and 94b discharge, the charge stored in capacitors 93b and 94b is transferred to one of capacitors 93a, 94a, 93c, and 94c located in the other stage. Capacitors 93a, 94a, 93c, and 94c, which are charged by the discharge of capacitors 93b and 94b, respectively, light up LED lamp 91a or LED lamp 91c. Because capacitors 93a, 94a, 93c, and 94c are charged by the discharge of capacitors 93b and 94b, the LED lamps 91a, 91b, and 91c flash at different timings. This improves visibility. Similarly, when capacitors 93c and 94c discharge, the charge stored in capacitors 93c and 94c is stored in one of capacitors 93a, 94a, 93b, and 94b located in the other stage. Capacitors 93a, 94a, 93b, and 94b, which are charged by the discharge of capacitors 93c and 94c, respectively, light up LED lamp 91a or LED lamp 91b. The LED lamps 91a, 91b, and 91c blink at different timings due to the charging of the capacitors 93a, 94a, 93b, and 94b caused by the discharging of the capacitors 93c and 94c, thereby improving visibility.

[0030] In this way, in the pressure detector 20 according to the third embodiment, one of the LED lamps 91a, 91b, and 91c lights up at a timing different from the other LED lamps 91a, 91b, and 91c. By lighting up the LED lamps 91a, 91b, and 91c at different timings, visibility can be improved compared to when the LED lamps 91a, 91b, and 91c are all turned on simultaneously. Furthermore, by making the optical axis directions of the LED lamps 91a, 91b, and 91c different, the viewing angle of the notification unit 12 can be widened, thereby improving visibility.

[0031] Furthermore, even if a short circuit occurs between LED lamp 91a and LED lamp 91c and current does not flow through LED lamp 91b, current still flows through LED lamps 91a and 91c, so the notification unit 12 does not completely stop displaying that DC voltage is being applied to the power transmission cable 9. Similarly, even if current does not flow through LED lamp 91a due to the short circuit, current still flows through LED lamps 91b and 91c, so the notification unit 12 does not completely stop displaying that DC voltage is being applied to the power transmission cable 9. Furthermore, even if current does not flow through LED lamp 91c due to the short circuit, current still flows through LED lamps 91a and 91b, so the notification unit 12 does not completely stop displaying that DC voltage is being applied to the power transmission cable 9. In this way, the pressure detector 20 according to the third embodiment can continue displaying that DC voltage is being applied to the power transmission cable 9 even if current does not flow through some of the LED lamps 91a, 91b, and 91c due to the short circuit.

[0032] Furthermore, by making the optical axis directions of the LED lamps 91a, 91b, and 91c different, the viewing angle of the notification unit 12 can be widened and the visibility can be improved.

[0033] The configurations shown in the above embodiments are merely examples of the content, and may be combined with other known technologies, or parts of the configurations may be omitted or modified without departing from the spirit of the invention.

[0034] Various aspects of the present disclosure are summarized below as appendices.

[0035] (Appendix 1) a detection unit that includes a core wire of a sheath earth provided in a DC circuit and an electrode portion provided at a distance from the core wire of the sheath earth, has a capacitor that is charged by a ripple component included in a DC voltage applied to the DC circuit, and detects the ripple component; a notification unit that operates by receiving power from the capacitor and notifies that the ripple component has been detected by the detection unit. (Appendix 2) The pressure detector according to claim 1, wherein the notification unit includes a light-emitting diode lamp that emits light upon receiving power from the capacitor. (Appendix 3) The pressure detector according to claim 2, wherein the notification unit includes a plurality of the light-emitting diode lamps. (Appendix 4) 4. The pressure detector according to claim 3, wherein the plurality of light-emitting diode lamps each have a different optical axis direction. (Appendix 5) the notification unit includes a plurality of the light-emitting diode lamps and a plurality of light-emitting diode capacitors; A pressure detector as described in Appendix 3 or Appendix 4, characterized in that a plurality of the light-emitting diode lamps are connected in series, and a plurality of the light-emitting diode lamps and a plurality of the light-emitting diode capacitors are connected in parallel with each other. (Appendix 6) A pressure detector as described in any one of Supplementary Note 1 to Supplementary Note 5, characterized in that it comprises an insulating support part that supports the electrode part so that the distance between the core wire of the sheath earth and the electrode part is a predetermined distance. (Appendix 7) 7. The pressure detector according to claim 6, wherein the insulating support part is a dielectric having a higher dielectric constant than air. (Appendix 8) 8. The pressure detector according to claim 1, further comprising a cover formed of a waterproof material for the detection unit. (Appendix 9) The electrode portion has a plurality of parts, A pressure detector according to any one of Supplementary Note 1 to Supplementary Note 8, characterized in that it comprises a switch for switching the number of electrode units among the plurality of electrode units that supply power to the notification unit. [Explanation of symbols]

[0036] 1 electric vehicle, 2 overhead line, 3 rail, 4 substation, 5 high-voltage distribution system, 6 transmission line, 7 transformer, 8 rectifier, 9 transmission cable, 10 sheath earth, 11 detection unit, 12 notification unit, 13 switch, 20 pressure detector, 30 railway equipment, 31 receiver, 32 display, 80 pressure detection system, 91a, 91b, 91c, 121 LED lamp, 92a, 92b, 92c IC chip, 93a, 93b, 93c, 94a, 94b, 94c capacitor, 111, 111a, 111b electrode unit, 112, 112a, 112b insulating support unit, 113 hole, 122 transmitter.

Claims

1. a detection unit that includes a core wire of a sheath earth provided in a DC circuit and an electrode portion provided at a distance from the core wire of the sheath earth, has a capacitor that is charged by a ripple component included in a DC voltage applied to the DC circuit, and detects the ripple component; a notification unit that operates by receiving power from the capacitor and notifies that the ripple component has been detected by the detection unit.

2. 2. The pressure detector according to claim 1, wherein the notification unit includes a light-emitting diode lamp that emits light when power is supplied from the capacitor.

3. 3. The pressure detector according to claim 2, wherein the notification unit includes a plurality of the light-emitting diode lamps.

4. 4. The pressure detector according to claim 3, wherein the plurality of light-emitting diode lamps have optical axes in different directions.

5. the notification unit includes a plurality of the light-emitting diode lamps and a plurality of light-emitting diode capacitors; 4. The pressure detector according to claim 3, wherein the plurality of light-emitting diode lamps are connected in series, and the plurality of light-emitting diode lamps and the plurality of light-emitting diode capacitors are connected in parallel with each other.

6. 2. The pressure detector according to claim 1, further comprising an insulating support portion that supports the electrode portion so that the distance between the core wire of the sheath earth and the electrode portion is set to a predetermined distance.

7. 7. The pressure detector according to claim 6, wherein the insulating support portion is made of a dielectric material having a relative dielectric constant greater than that of air.

8. The pressure detector according to claim 1, further comprising a cover formed of a waterproof material for the detection unit.

9. The electrode portion has a plurality of parts, The pressure detector according to claim 1 , further comprising a switch for switching the number of the electrode units that supply power to the notification unit among the plurality of electrode units.

10. a step of charging a capacitor constituted by a core wire of a sheath earth provided in a DC circuit and an electrode portion provided at a distance from the core wire of the sheath earth with a ripple component included in a DC voltage applied to the DC circuit; detecting the ripple component; notifying that the ripple component has been detected by receiving power from the capacitor; A pressure detection method comprising:

11. a voltage detector that detects a voltage applied to a DC circuit, and a receiver that receives a voltage detection signal; The pressure detector is a detection unit that includes a core wire of a sheath earth provided on the DC circuit and an electrode portion provided at a distance from the core wire of the sheath earth, has a capacitor that is charged by a ripple component included in a DC voltage applied to the DC circuit, and detects the ripple component; a transmitter that receives power from the capacitor and operates, and transmits the detection signal to the receiver to notify that the ripple component has been detected by the detection unit; A pressure detection system comprising:

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