Non-contact type charge display

Abstract

To provide a non-contact type charge display capable of indicating whether object equipment such as a cable related to electrical installations is charged without contacting a live part.SOLUTION: In a non-contact type charge display A that detects whether object equipment is charged without contact and displays the detection result, a detection circuit 6 has a first electrode 1 for measuring the voltage applied to the object equipment and a second electrode 2 for measuring the voltage relative to ground via capacitance, and comprises a circuit that outputs a signal from the detection circuit 6 when voltage is applied to the object equipment, where the first electrode 1 comprises a plate having a fixed area and is positioned at a predetermined distance from the object equipment, the second electrode 2 has a shape that minimizes its vertical projected area relative to the first electrode 1 while maximizing its area relative to the ground, and is positioned such that it is separated from the ground by a dielectric.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a non-contact charging indicator that indicates whether or not a target device such as a cable related to electrical equipment is being charged without touching a charging unit. [Background technology]

[0002] With conventional high-voltage voltage detectors, checking for the presence or absence of voltage (charging) in the target device is done using an electrically unshielded part. Even when measuring high voltage, measurements are taken in an electrically unshielded part, with a VT (voltage transformer) or similar device attached. In other words, checking for the presence or absence of voltage (charging) is usually done in an unshielded part.

[0003] Because this voltage detection method is performed in unshielded areas (i.e., areas with high electrical risk), especially in the case of high voltage or higher, a charging indicator that shows whether or not the target device, such as a cable, is being charged cannot be attached unless the device is in a power outage. Charging indicators are effective in preventing electric shock to workers during inspections and construction of electrical equipment. However, in order to attach a charging indicator to the target device, a power outage must be initiated beforehand.

[0004] For electricity consumers, two power outages are required: 1) for installing charging display devices, and 2) for inspecting and carrying out construction work on electrical equipment. With the recent spread of ICT (Information and Communication Technology), it has become increasingly difficult to even cause power outages. Even if it is for the safety of the work, an increase in the number of power outages is contrary to the interests of consumers. Furthermore, it increases the workload (number of work tasks and work processes) for those carrying out the work, which ultimately translates into a financial burden on the consumer side.

[0005] Furthermore, when measuring with a VT, the equipment requires Class A grounding, which results in a large-scale installation.

[0006] Therefore, a configuration has been disclosed that can detect whether a target device is being charged or not without contacting the power source of the target device, such as a charging cable. More specifically, a configuration has been disclosed in which the current flowing through the target device, such as a cable, is used to display whether or not the device is being charged, based on the principle of electromagnetic induction. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-227090 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0008] However, while the configuration of Patent Document 1 certainly allows for non-contact detection of the power source of a charged cable, it cannot detect whether charging is occurring if no current is flowing through the cable. In other words, although a voltage is applied to the cable, it cannot detect a state where there is no load (no current is flowing). In particular, during periodic inspections of electrical equipment, the above-mentioned state is often anticipated, making it useless from the perspective of protecting workers and others from electric shock. Furthermore, this technology can only detect parts that are not electrically shielded. Therefore, even when using this technology, it is necessary to put the target equipment into a power outage state.

[0009] Therefore, in order to solve the above-mentioned problems, the present invention aims to provide a non-contact charging display device that can detect whether or not a target device such as a cable related to electrical equipment is charging without contacting the charging part and can be safely attached to an electrically shielded part (= a part with high electrical safety). [Means for solving the problem]

[0010] Specifically, the invention of claim 1 is as follows: A non-contact charging display device that detects whether a target device is being charged without contact and displays the detection result, the detection circuit has a first electrode for measuring a voltage applied to the target device, and a second electrode for measuring a voltage via a capacitance with respect to the ground; a circuit for outputting a signal from the detection circuit when a voltage is applied to the target device; the first electrode is made of a plate having a certain area and is disposed at a predetermined distance from the target device; The second electrode has a shape that reduces the vertical projection area relative to the first electrode and increases the area relative to the ground, and is arranged so as to interpose a dielectric between it and the ground, making it a non-contact charging display device.

[0011] The invention of claim 2 is as follows: The target device is a cable, The non-contact charging display device according to claim 1, wherein the dielectric interposed between the cable and the ground covers a shielding layer within the cable.

[0012] The invention of claim 3 is as follows: The first electrode measures a voltage applied to a live part of the cable, which is a target device; the second electrode is provided at a contact portion of a cable gripping portion that grips the cable; The non-contact charging display device according to claim 2, wherein when the cable is gripped by the cable gripping portion, the second electrode is close to the outer periphery of the cable.

[0013] The invention of claim 4 is as follows: the first electrode has a first antenna, a second antenna, and a differential amplifier; the differential amplifier is connected to the first antenna and the second antenna; receiving a potential detected by the first antenna and a potential detected by the second antenna; In the non-contact charging display device according to any one of claims 1 to 3, when the detected potentials are different, a potential related to the difference is output. [Effects of the Invention]

[0014] According to the present invention, it is possible to detect and display whether a target device such as a cable is charging without touching the charging part. For example, even if the voltage detection operation is forgotten or the charging state of the target device changes after voltage detection, it is possible to warn those around that the target device is charging. This is convenient because it can prevent users such as workers from accidentally touching the target device.

[0015] In particular, according to the invention of claim 4, even if an electric field induced by a voltage applied to a device other than the target device, such as a bus bar in a charging state, exists nearby, the capacitance between the non-contact charging display device according to the present invention and the device other than the target device is reduced, thereby reducing the influence of the electric field, making it difficult to detect the voltage applied to the device other than the target device, and the voltage V generated in the target device. 02 can be captured with certainty. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a diagram showing the configuration of a non-contact charging and display device according to a first embodiment of the present invention. [Figure 2] 1 is a schematic diagram illustrating the detection principle of a non-contact charging display device according to a first embodiment of the present invention, and the configuration of a cable having a shielding layer, which is a target device. [Figure 3] 1(a) and 1(b) are equivalent circuit diagrams showing the detection principle in which a non-contact charging display device according to a first embodiment of the present invention is capacitively coupled to a cable, which is a target device, and thereby detects the presence or absence of a voltage V02 by detecting a voltage VC2 applied to a detection circuit due to an electric field induced by a voltage V02 applied to the cable. [Figure 4] 1(a) and 1(b) are explanatory diagrams illustrating the configuration of a first electrode of the non-contact charging display device according to the first embodiment of the present invention. [Figure 5] 1 is a configuration diagram of a detection circuit in the non-contact type charging display device according to the first embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0017] (Embodiment Example 1) A method for detecting the charging state of a target device and a non-contact charging and display device A according to a first embodiment of the present invention will be described below with reference to the drawings. In the first embodiment, a cable K is used as the target device for detecting whether charging is performed.

[0018] As shown in Fig. 1, the non-contact charging display device A of the first embodiment of the present invention is mainly composed of a clip-shaped cable gripping member 3 that grips the outer periphery of a cable K, which is an example of a target device, and a warning light member 4 that issues a warning to those in the vicinity with light. Note that Fig. 1 shows a front view, a left side view, a right side view, a plan view, and a bottom view of the non-contact charging display device A.

[0019] The cable gripping member 3 includes a handle portion 32 that a user such as an operator grasps from both sides with the thumb and other fingers to open the cable gripping portion 31, and the cable gripping portion 31 that grips the outer periphery of the cable K. A spring (not shown) is provided inside the cable gripping member 3, and this spring biases the cable gripping member 3 to close the cable gripping portion 31.

[0020] Furthermore, the second electrode 2 is provided in a strip-like shape along the short direction of the cable gripping member 3 on the contact portion 311 of the cable gripping member 31 that comes into contact with the outer periphery of the cable K when the cable K is gripped. Therefore, when the cable gripping member 31 grips the cable K, the strip-like second electrode 2 wraps around (or comes into close contact with) the outer periphery of the cable K. Note that, although the first embodiment shows a configuration in which the second electrode 2 wraps around (or comes into close contact with) the outer periphery of the cable K, the present invention is not limited to this configuration, and any configuration in which the second electrode 2 is close to the outer periphery of the cable K without coming into contact with the cable K is acceptable.

[0021] A cylindrical section 33 having a semicircular cross section is provided on one side of the cable gripping section 31, and the warning light member 4 is provided approximately in the center in the longitudinal direction of the cylindrical section 33. A strip-shaped first electrode 1 is provided inside each of the two longitudinal ends of the cylindrical section 33, sandwiching the warning light member 4 therebetween, along the inner periphery of the cylindrical section 33.

[0022] The warning light member 4 detects a voltage V between the first electrode 1 and the second electrode 2 from a detection circuit 6 (described later). C2 occurs and when a signal is received from the comparison circuit 63, a light is emitted to warn those in the vicinity.

[0023] Next, the configuration of cable K will be described using Figure 2. Cable K is a CVT (cross-linked polyethylene insulated vinyl sheath cable), a type of high-voltage cable to which a voltage of, for example, 6600V is applied. A conductor (live portion 51) through which current flows is provided at the center of cable K. This conductor (live portion 51) is covered on its outer periphery with an insulator 52 made of, for example, cross-linked polyethylene, which insulates it from the ground. This insulator 52 is covered on its outer periphery with a shielding layer 53 made of, for example, copper tape. The shielding layer 53 is a metal layer that is grounded (GND, earth potential bonded) and serves as a return path for ground-fault current. The shielding layer 53 is also covered on its outer periphery with a vinyl sheath 54. The vinyl sheath 54 is the vinyl exterior of cable K and serves to protect cable K from external damage and water.

[0024] Next, the detection principle of the non-contact charging display device A according to the present invention and the configuration of the first electrode 1 and the second electrode 2 based on this detection principle will be described with reference to Figures 2 and 3. Figures 2 and 3 show the detection principle of the non-contact charging display device A according to the present invention. Here, C1 is the capacitance between the conductor (charging section 51) of the cable K and the first electrode 1, C 21 is the capacitance between the first electrode 1 and the second electrode 2, C 22 is the capacitance between the conductor (charging part 51) of the cable K and the second electrode 2, C 31 is the capacitance between the first electrode 1 and the ground GND, C 32is the capacitance between the second electrode 2 and the shield layer 53 of the cable K (since the shield layer 53 of the cable K is grounded, it is electrically equivalent to the ground GND).

[0025] The non-contact charging display device A is provided with a first electrode 1 for measuring the voltage applied to the conductor (charging section 51) of the cable K, and a second electrode 2 for measuring the voltage via capacitance with respect to the ground GND. In addition, a detection circuit 6 is provided between the first electrode 1 and the second electrode 2.

[0026] The total combined capacitance of this non-contact charging display device A is expected to be expressed by the following formula 1. Also, the voltage V generated between the first electrode 1 and the second electrode 2 is C2 This V C2 is the voltage at which detection is possible.

[0027]

number

[0028]

number

[0029] From the above equation 2, we increase C1 and 21 If you reduce V C2 becomes larger, and the effective V C2 Also, C 32 If is large, more effective V C2 Also, C 22 If is small, the current flowing through the detection circuit 6 can be increased, which is advantageous for detection.

[0030] Therefore, by increasing the area S of the first electrode 1 and increasing the directivity to the cable K, "S" in C=εS / d is increased, and thus C1 is increased. Also, by reducing the vertical projection area of ​​the first electrode 1 relative to the second electrode 2, C 21 was made smaller.

[0031] Furthermore, there are two contradictory requirements for the first electrode 1: that it be easy to perform detection based on Fig. 3 for the cable K, and that it be difficult to perform detection based on Fig. 3 for devices other than the target device, such as a bus bar in a charged state. Therefore, the first electrode 1 needs to have high directivity with respect to the electric field of the detection target, such as the electric field of the conductor (charging section 51) of the cable K. The configuration of the first electrode 1 for this purpose will be specifically described using Fig. 4.

[0032] The first electrode 1 has an antenna 11, an antenna 12, and a differential amplifier 13. The antenna 11 is disposed at a predetermined distance from an unshielded conductor (charging unit 51) of the cable K. The "predetermined distance" is a distance at which the first electrode 1 can perform detection of the cable K based on FIG. 3(b). It is also a safe distance at which a user, such as a worker installing the first electrode 1, will not be electrocuted by a voltage applied to the unshielded conductor (charging unit 51) of the cable K.

[0033] The antenna 12 is disposed at a position farther from the unshielded conductor (charging portion 51) of the cable K than the antenna 11.

[0034] The differential amplifier 13 is connected to the antenna 11 and the antenna 12, and receives the potential detected by the antenna 11 and the potential detected by the antenna 12. When the potentials detected by the antenna 11 and the antenna 12 are the same, the differential amplifier 13 does not output a potential. On the other hand, when the detected potentials are different, the differential amplifier 13 outputs a potential corresponding to the difference.

[0035] Therefore, for example, as shown in FIG. 4(a), when detecting a device other than the target device, such as a busbar in a charged state, based on FIG. 3(b), the same potential occurs in antenna 11 and antenna 12 (input 1 in antenna 11, input 1 in antenna 12), so no difference occurs (input 1 - input 1 = 0), and the differential amplifier 13 does not output a potential.

[0036] On the other hand, as shown in Figure 4(b), when detecting cable K based on Figure 3(b), cable K is close to antenna 11 but far from antenna 12 (input 1 to antenna 11, input 0 to antenna 12), so a difference occurs in the detected potential (input 1 - input 0 = 1), and differential amplifier 13 outputs a potential (≒ voltage) related to this difference.

[0037] In addition, the second electrode 2 has a smaller vertical projection area relative to the first electrode 1 to reduce the above "S" and 21 Also, by reducing the vertical projection area of ​​the cable K, the above "S" is reduced, and the above C 22 In addition, by wrapping the second electrode 2 around (or adhering to) the shielding layer 53 of the cable K, such as a shielding copper tape, the second electrode 2 can be reliably and strongly capacitively coupled to the earth GND (ground), thereby reducing C 32 Make it bigger.

[0038] With these configurations, the voltage V generated between the first electrode 1 and the second electrode 2 C2 In addition, the configuration of the antenna 11 and the antenna 12 associated with the first electrode 1 makes it difficult to detect, based on FIG. 3(b), a live part other than the target device, such as a bus bar in a charged state, and the voltage V generated in the target device is 02 can be captured with certainty.

[0039] The shapes of the first electrode 1 and the second electrode 2 are not limited to those shown in FIGS.

[0040] As shown in FIG. 5, the detection circuit 6 is configured such that the C 21 The voltage V generated by the current signal flowing through C2The detection circuit 6 is provided with an amplifier circuit 61 that amplifies the signal, and a reference voltage generation circuit 62. A comparison circuit 63 compares the output signal of the amplifier circuit 61 with the output signal of the reference voltage generation circuit 62, and if a difference occurs, outputs a signal to the warning light component 4. The combination of the reference voltage generation circuit 62 and the comparison circuit 63, or the combination of the amplifier circuit 61, the reference voltage generation circuit 62, and the comparison circuit 63, constitutes a "circuit that outputs a signal from the detection circuit 6." The detection circuit 6 is also provided with a power supply 64, and power is supplied to each circuit in the detection circuit 6 by turning on a switch 65 of the power supply 64.

[0041] Next, we will explain how to detect the charging state of the target device using the non-contact charge display device A of the present invention. A user such as an operator grasps the handle portion 32 from both sides with the thumb and other fingers, opens the cable gripping portion 31, and grips the outer periphery of the cable K, which is the target device.

[0042] When a voltage is applied to cable K, this voltage causes cable K to 02 The first electrode 1 has a potential V 02 The voltage of the second electrode 2 is divided by the capacitance C1 and becomes the potential V2. The voltage of the second electrode 2 is 21 and C 32 The capacitance C generated by this outflow current i is 21 potential difference V between C2 The detection circuit 6 detects the capacitance C 21 potential difference V C2 If the amplified output signal is greater than the reference voltage, the warning light member 4 displays a warning light.

[0043] In this way, the non-contact charge display device A of the present invention can detect and display whether or not a target device such as a cable K is being charged, without touching the conductor (charging section 51). For example, even if voltage detection is forgotten or the charging state of the target device changes after voltage detection, it is possible to warn those around that the target device is in a charging state. Therefore, users such as workers can visually recognize that voltage is being applied to the target device, and are prevented from accidentally touching the target device such as a cable K, which is convenient.

[0044] In the first embodiment, the non-contact charging display device A displays the warning with light using the warning light member 4, but the configuration is not limited to this. For example, the non-contact charging display device A may be configured to output the warning as sound using a sound generating circuit (not shown), or may be configured to output the warning as a combination of light and sound using the warning light member 4 and a sound generating circuit.

[0045] In the first embodiment, the detection circuit 6 is configured by combining elements such as the amplifier circuit 61, the reference voltage generating circuit 62, and the comparator circuit 63, but the configuration is not limited to this. For example, the detection circuit 6 has a control unit (not shown) realized by a microcomputer consisting of a single LSI, and the control unit detects the voltage V detected by the first electrode 1 and the second electrode 2. C2 Based on the reference voltage, the voltage V C2 However, if the voltage is greater than the reference voltage, the warning light member 4 may be configured to display a warning light.

[0046] In the first embodiment, the voltage V detected by the first electrode 1 and the second electrode 2 is C2 Based on the reference voltage, the voltage V C2 In the above example, the warning light 4 displays a warning by light if the voltage is greater than the reference voltage, but the present invention is not limited to this configuration. For example, in addition to the configuration in which a warning is output when the target device is in a charging state, a configuration in which an output is output when the target device is not in a charging state may be adopted. More specifically, the capacitance C generated by the outflow current i 21potential difference V between C2 If the detection circuit 6 does not detect the capacitance C 21 potential difference V C2 If the amplified output signal is equal to or lower than the reference voltage, the warning light member 4 may be configured to indicate that the target device is not in a charging state. By indicating this not only when the target device is in a charging state but also when it is not in a charging state, a user such as an operator can clearly recognize that the target device is not in a charging state, which is convenient.

[0047] Although the first embodiment has been described above, it is presented as an example and is not intended to limit the scope of the invention. The present invention can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the inventions and their equivalents set forth in the claims. [Explanation of symbols]

[0048] A: Non-contact charging indicator, GND: Ground, K: Cable, 1: first electrode, 11: antenna, 12: antenna, 13: differential amplifier, 2: second electrode, 3: Cable gripping member, 31: Cable gripping portion, 311: Contact portion, 32: Handle portion, 33: Cylindrical portion, 4: Warning light components, 51: live part, 52: insulator, 53: shielding layer, 54: vinyl sheath, 6: detection circuit, 61: amplifier circuit, 62: reference voltage generation circuit, 63: comparison circuit, 64: power supply, 65: switch

Claims

1. A non-contact charging display device that detects whether a target device is being charged without contact and displays the detection result, the detection circuit has a first electrode for measuring a voltage applied to the target device, and a second electrode for measuring a voltage via a capacitance with respect to the ground; a circuit for outputting a signal from the detection circuit when a voltage is applied to the target device; the first electrode is made of a plate having a certain area and is disposed at a predetermined distance from the target device; A non-contact charging display device characterized in that the second electrode has a shape that reduces its vertical projection area relative to the first electrode and increases its area relative to the ground, and is arranged so as to interpose a dielectric between it and the ground.

2. The target device is a cable, The non-contact charging display device according to claim 1 , wherein the dielectric interposed between the cable and the ground covers a shielding layer within the cable.

3. The first electrode measures a voltage applied to a live part of the cable, which is a target device; the second electrode is provided at a contact portion of a cable gripping portion that grips the cable; The non-contact charging display device according to claim 2 , wherein the second electrode is adjacent to an outer periphery of the cable when the cable is gripped by the cable gripping portion.

4. the first electrode has a first antenna, a second antenna, and a differential amplifier; the differential amplifier is connected to the first antenna and the second antenna; receiving a potential detected by the first antenna and a potential detected by the second antenna; 4. The non-contact charging display device according to claim 1, wherein when the detected potentials are different, a potential corresponding to the difference is output.

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