JP5776110B2 - Degradation indicator - Google Patents

Description

  The present invention is connected to a grounding wire of a power distribution material such as a transformer, a switch or a lightning arrester installed in a transmission / distribution line facility, and detects a leakage current flowing through the grounding wire due to the deterioration of the power distribution material. The present invention relates to a deterioration indicator that displays deterioration of a battery.

    For example, when an abnormal voltage occurs due to a lightning strike to the high-voltage transmission / distribution line facility or its vicinity, or switching on / off of a switch or circuit breaker, various devices / equipment connected to the transmission / distribution line facility are In order to protect, it is common to install a high-voltage lightning arrester between the power transmission side and the grounding side of the transmission and distribution line equipment. In this type of lightning arrester, a zinc oxide varistor having a function of interrupting a continuity is widely used as a device for limiting a transient overvoltage caused by a direct lightning strike or an induced lightning and discharging a surge current to the ground.

  The protective element in this type of lightning arrester deteriorates due to repeated application of surge voltage, and the leakage current gradually increases. For this reason, a deterioration indicator is connected in advance between the ground-side terminal of the lightning arrester and the ground, and the presence or absence of the deterioration is visually detected from the outside. The applicant places a deterioration indicator with a thermal fuse between the grounding terminal of the lightning arrester and the ground, and when this thermal fuse generates heat due to a leakage current and reaches a temperature above a predetermined value, it blows. The deterioration indicator which displays the deterioration of a lightning arrester using the phenomenon to do is proposed previously (for example, refer patent document 1).

JP-A-8-203415

  By the way, in the deterioration indicator disclosed by the above-mentioned patent document 1, the conductive resin fuse blown for deterioration display cannot be restored to the original state, and is used only once. For this reason, when a lightning arrester having a deteriorated protective element is replaced with a new lightning arrester, it is necessary to replace the conductive resin fuse with a new one for the deterioration indicator attached thereto. If the fuse is replaced at the time of replacing the lightning arrester, a series of operations becomes complicated, and it is actually very difficult to perform these operations at the site of replacing the lightning arrester. For this reason, when inspecting whether or not the lightning arrester has deteriorated, it is necessary to replace not only the lightning arrester but also the deterioration indicator. When inspecting the lightning arrestor, the deterioration indicator must always be carried. The business is very complicated, and it is strongly desired to realize a deterioration indicator capable of easily returning the deterioration display to the non-deterioration display state at the replacement work site. Also, other transformers and switches may cause leakage currents that cannot be ignored due to deterioration over time, and it is easy to check for deterioration when mounted on transmission and distribution line equipment. There is a need for a deterioration indicator that can be visually discriminated and that can be used repeatedly.

  Therefore, the present invention has been proposed in view of the above-described improvements, and the object of the present invention is to make a deterioration display non-deterioration display by a simple means even at a replacement site of equipment such as a lightning arrester. An object of the present invention is to provide a deterioration indicator having a simple structure that can be easily and surely restored and can be repeatedly used.

  As a technical means for achieving the above-mentioned object, the present invention is connected to a grounding wire of a power distribution material installed in a transmission / distribution line facility, detects a leakage current of the power distribution material flowing in the grounding wire, and reduces its deterioration. A display that is housed in the housing so as to be capable of transition between a non-display state that indicates that the electrical distribution material can be considered normal or normal and a display state that indicates that it has deteriorated. The display unit is made non-displayed by attracting the plunger and the plunger attached to the display unit with a magnetic force, and a magnetic force that substantially cancels the attractive magnetic force by a leakage current exceeding a predetermined value appears. And a self-holding solenoid that brings the display unit into a display state by releasing the suction of the plunger, and a jig having a magnet of the same polarity as the magnet provided on the display unit is attached to the outside of the housing. Characterized in that so as to transition from the display state the display unit in the magnetic repulsive force acting between the magnets by proximity to the display unit in the display state to the non-display state.

  In the deterioration indicator of the present invention, the display unit is normally not displayed by the self-holding solenoid attracting the plunger with a magnetic force. On the other hand, when the electrical distribution material deteriorates, the leakage current flowing through the grounding wire increases due to the deterioration of the electrical distribution material. When a leakage current exceeding a certain value flows, the self-holding solenoid is caused to generate a magnetic force that substantially cancels the magnetic force for attracting and holding the plunger, thereby releasing the attracted state of the plunger. By releasing the plunger, the display unit is shifted from the non-display state to the display state, and the display unit is set to the display state.

  When a jig having a magnet having the same polarity as the magnet provided in the display unit is brought close to the display unit from the outside of the housing, the display unit is caused by the magnetic repulsive force of both magnets. Transition from the display state of deterioration to the normal non-display state. In this way, when the display is restored from the deterioration display state to the normal state, that is, the non-display state, the display unit can be operated from the outside of the housing with a simple operation using a dedicated jig without disassembling the deterioration indicator. Can be returned from the display state to the non-display state and returned to the normal state, so that the deterioration indicator can be easily used repeatedly.

  In the deterioration indicator of the present invention, the housing is composed of a cylindrical member having at least a lower part that is transparent, the self-holding solenoid is disposed in the central part of the housing, and the display part is disposed between the central part and the lower part of the housing. It is desirable to have a structure in which the display unit in the display state can be visually observed at the lower part of the housing. Since the deterioration indicator as in the present invention is attached to a high place in the vicinity where the electric distribution equipment for the transmission and distribution line equipment is installed, the transparent lower portion of the housing is provided below the transparent lower portion of the housing. It becomes easy to see from 360 degrees, and it becomes easy for an inspector or the like to recognize the display unit in the display state. Of course, there is no need for replacement of parts as in the conventional product, and the necessity of preparing parts for replacement of parts and the need for carrying them are also eliminated when investigating deteriorated equipment.

  The self-holding solenoid according to the present invention preferably has a structure attached to a fixed portion in the housing via an elastic member. As described above, the deterioration indicator is attached to a high place in the vicinity where the power distribution equipment for the transmission / distribution line equipment is installed, so that the housing may be subjected to an impact due to falling snow, a gust of wind, or birds. . Even when such an impact is applied to the housing, it is possible to effectively suppress the self-holding solenoid from vibrating due to the impact by the buffering action of the elastic member. Thus, it is possible to reliably avoid a malfunction in which the plunger of the self-holding solenoid is released from the state in which the plunger is sucked and held by vibration due to an impact and the display unit shifts from the non-display state to the display state.

  The self-holding solenoid according to the present invention rectifies the voltage at both ends generated by the leakage current flowing through the detection resistor connected between the power application side terminal and the ground side terminal by the rectifier circuit, and substantially cancels the attractive magnetic force. A structure having a drive circuit for generating a magnetic force is desirable. If a drive circuit for a self-holding solenoid is configured in this way, a resistor having a small resistance value can be used as a leakage current detection resistor by setting the rated voltage of the self-holding solenoid low. Further, it is not necessary to separately prepare a power source for driving the self-holding solenoid.

  The drive circuit according to the present invention has a detection resistor and a pair of contacts connected to each of the terminals between the power application side terminal and the ground side terminal, and has a magnetic force that substantially cancels the attractive magnetic force due to the leakage current. It is desirable to have a structure having a short circuit that closes both contacts when the plunger is released by suction. If a drive circuit for a self-holding solenoid is configured as described above, a leakage current flows through the short circuit, so that the self-holding solenoid can be protected even if a large leakage current occurs. In addition, since a detection resistor having a relatively small resistance value can be used, it is possible to remarkably reduce the influence of an increase in the grounding resistance of the power distribution material due to the provision of the detection resistor.

The short circuit according to the present invention is fixedly disposed in the housing, and is attached to a pair of conductive fixing pieces provided between the charging-side terminal and the ground-side terminal, and a display unit provided so as to be movable in the housing. Conductive movable piece that comes into contact with and electrically connects a pair of conductive fixed pieces as contacts at the time of releasing the attraction of the plunger by generating a magnetic force that substantially cancels the attractive magnetic force due to leakage current A structure composed of and is desirable. If the short circuit of the self-holding solenoid is configured in this way, the short circuit can be formed with a simple mechanism comprising a pair of conductive fixed pieces and a conductive movable piece for connecting between them during display operation. .

  According to the present invention, a magnetic repulsive force of both magnets is obtained by bringing a jig having a magnet of the same polarity as the magnet provided in the display unit to the display unit from the outside of the housing in the display state. By moving the display unit from the display state to the non-display state, the display unit can be moved from the display state to the non-display state with a simple operation from the outside of the housing using a dedicated jig without disassembling the deterioration indicator. Thus, it is possible to return to the normal state, and it becomes easy to repeatedly use the deterioration indicator. As a result, at the time of replacement work due to deterioration of the power distribution equipment, the return operation of the deterioration indicator can be performed very easily, and the workability is greatly improved.

In embodiment of this invention, it is sectional drawing which shows the non-display state of a display part by the internal structure of the housing in a deterioration display. It is sectional drawing which shows the display state of a display part by the internal structure of the housing in the deterioration display of FIG. It is a schematic block diagram which shows the connection state of the electrical distribution material with respect to a transmission / distribution electric wire and the deterioration indicator. It is a front view which shows the state which attached the deterioration indicator to the utility pole. It is a front view which shows the state which isolate | separated the cover and housing of the deterioration indicator. It is a circuit diagram which shows the internal circuit structure of a deterioration indicator. It is a front view which shows the state which made the jig | tool approach the degradation indicator of FIG. It is a principal part expanded sectional view of FIG. It is a fragmentary sectional view which shows the modification of the attachment structure of the self-holding-type solenoid of FIG. It is a fragmentary sectional view which shows the other modification of the attachment structure of the self-holding-type solenoid of FIG.

  An embodiment of the deterioration indicator according to the present invention will be described in detail below. In the following embodiments, a case where the high voltage lightning arrester (hereinafter simply referred to as a lightning arrester) is applied as a power distribution material installed in the transmission / distribution line facility will be described. Is possible.

  As shown in FIG. 3, the deterioration indicator 1 is connected to a grounding wire 4 of a lightning arrester 3 installed on a power pole or the like that supports the transmission and distribution line 2, and a leakage current that flows through the grounding wire 4 due to the deterioration of the lightning arrester 3. Is detected and the deterioration of the lightning arrester 3 is displayed. As shown in FIGS. 4 and 5, the deterioration indicator 1 is provided with an opaque resin cover 15 having weather resistance on the upper part 12 and the central part 13 of a cylindrical housing 11 made of transparent resin constituting the display body. Thus, the upper portion 12 and the central portion 13 of the housing 11 are covered and protected, and the lower portion 14 of the housing 11 is exposed so that a display portion 18 described later can be seen. The deterioration indicator 1 is provided with a power-side terminal 21 and a ground-side terminal 22 (see FIG. 1) on the upper portion 12 of the housing 11, and the power-side terminal 21 serves as an intermediate portion of the ground wire 4 of the lightning arrester 3. And is connected to the lightning arrester side, and is fastened and fixed to the utility pole 16 by a band 17 in a state where the ground side terminal 22 is connected to the ground side.

  As shown in FIGS. 1 and 2, the deterioration indicator 1 includes a display unit 18 housed in the housing 11 so as to be able to shift between a display state and a non-display state with respect to the deterioration of the lightning arrester 3, and a self-holding solenoid 20. It has a main part consisting of The self-holding solenoid 20 is accommodated in the housing 11, and when substantially de-energized or when a weak current having a value less than a predetermined value is energized, the plunger 19 attached to the display unit 18 resists the action of gravity. In this case, the display unit 18 is not displayed by being sucked and held in the housing upper part 12, and a magnetic force that substantially cancels the attractive magnetic force due to a leakage current having a value greater than or equal to a predetermined value is revealed to release the attractive state of the plunger 19. By doing so, it is dropped by its own weight in the housing lower part 14, and the display unit 18 is brought into a display state. 1 shows that the display unit 18 is in a non-display state, and FIG. 2 shows that the display unit 18 is in a display state.

  The upper portion 12 of the housing 11 is provided with a power application side terminal 21 and a ground side terminal 22 to which the ground wire 4 of the lightning arrester 3 is connected. By covering the conductive rods 23 and 24 (screw leg portions) extending vertically from each of the power application side terminal 21 and the ground side terminal 22 (screw head) to the lower portion 14 of the housing 11, the insulating materials 25 and 26 are coated. The two rods 27 and 28 reaching the vicinity of the bottom of the housing 11 are formed. The lower ends of the two rods 27 and 28 are connected by a support plate 29 made of a ferromagnetic metal.

  A flange 30 is formed at the boundary between the central portion 13 and the lower portion 14 of the outer peripheral surface of the housing 11, and as described above, the cover 15 that covers the upper portion 12 and the central portion 13 of the housing 11 (FIGS. 4 and 5). Reference) is locked by the flange 30. By adopting a structure in which the lower portion 14 of the transparent housing 11 located below the flange 30 is exposed from the cover 15, the display portion 18 is placed outside the housing 11 in a state where the display portion 18 is located at the lower portion 14. (See FIG. 2). The housing 11 is composed of a cover body that constitutes the upper part 12 and a housing body that is a bottomed cylindrical member that constitutes the central part 13 and the lower part 14, and an O-ring 31 is provided to the opening of the housing body. It has a seal structure with a lid attached.

  The display unit 18 is a bottomed cylindrical member made of resin, and is inserted into the two rods 27 and 28 so as to be vertically movable. 14 is arranged so as to be able to shift between the display states located at 14. The outer peripheral surface of the display unit 18 is colored with red or the like so that it can be easily seen. A concave portion 32 that opens downward is provided at the center of the display portion 18, and a magnet 34 that is fixed via an attachment member 33 is disposed in the vicinity of the opening end of the concave portion 32. A plunger 19 of a self-holding solenoid 20 is erected on the top plate portion of the recess 32 via a conductive movable piece 35.

  In the display state in which the display unit 18 is positioned on the lower part 14 of the housing 11, conductive fixed pieces 36 and 37 constituting a pair of contacts are provided on the rods 27 and 28 so as to contact the movable piece 35 described above. ing. The pair of fixed pieces 36 and 37 are attached so as to be in contact with the conductive rods 23 and 24 embedded in the axial centers of the rods 27 and 28. The movable piece 35 of the display unit 18 and the fixed pieces 36 and 37 of the rods 27 and 28 constitute a short circuit 48 described later. A hole 38 is formed at the center of the support plate 29 attached to the lower ends of the rods 27 and 28 so that the magnet 34 of the display unit 18 in the display state is not attracted. Further, the projections 39 formed at the bottom center portion of the housing 11 are fitted into the holes 38 of the support plate 29 described above, so that the two rods 27 and 28 are positioned.

  The self-holding solenoid 20 is attached to a rod 27 on the power application side, and is disposed above the plunger 19 that extends in the vertical direction from the display unit 18 at the central portion 13 of the housing 11. This self-holding solenoid 20 is attached to a power-applying rod 27 which is a fixed part in the housing 11 via an L-shaped metal fitting 40 which is an elastic member. The L-shaped bracket 40 is made of a plate material made of, for example, phosphor bronze having a spring property, and exhibits a function of absorbing an impact. One end of the horizontal portion of the L-shaped metal fitting 40 is fixed to the rod 27 on the power application side, and the self-holding solenoid 20 is fixed to the vertical portion via an insulating material 41.

  The plunger 19 has a tip 43 that is tapered so that the plunger 18 can be smoothly inserted into the inside 42 of the self-holding solenoid 20 when the display unit 18 moves upward, and a part of the plunger 19 is self-holding solenoid 20. The relative positional relationship with the self-holding solenoid 20 is set so as to be held by the magnetic force while entering the inside 42 (see FIG. 2). The self-holding solenoid 20 can be attached to the rod 28 on the ground side.

  A wiring board 44 on which circuit components (not shown in FIG. 1) of the deterioration indicator 1 are mounted is fixed to the housing 11 above the self-holding solenoid 20. A configuration circuit mounted on the wiring board 44 is shown in FIG. As shown in the figure, the self-holding solenoid 20 uses a rectifier circuit 46 to generate a voltage between both terminals generated by a leakage current flowing in a detection resistor 45 connected between the power application side terminal 21 and the ground side terminal 22. A drive circuit 47 is provided that rectifies and generates a magnetic force that cancels the majority of the attractive magnetic force based on the output of the rectifier circuit 46.

  The drive circuit 47 has a pair of contact points (corresponding to the conductive fixing pieces 36 and 37) respectively connected to the charging side terminal 21 and the ground side terminal 22 and is in a normal state, that is, the self-holding solenoid 20. When the plunger 19 is sucked and held, the self-holding solenoid 20 generates a magnetic force that substantially cancels the attractive magnetic force due to the leakage current, the plunger 19 is released by suction, and the movable piece 35 is naturally dropped. Is provided with a short circuit 48 that closes the aforementioned contacts by contacting the fixed pieces 36 and 37.

  By configuring the short circuit 48 in this way, it is possible to avoid leakage current from continuing to flow through the self-holding solenoid 20, so that damage such as burning of the self-holding solenoid 20 can be prevented and protection can be achieved. The detection resistor 45 having a small resistance value can be used without using the detection resistor 45 having a large resistance value, and the ground resistance can be reduced.

  In the structure of the deterioration indicator 1 (see FIGS. 1 and 2), a display state where the display unit 18 is located in the lower portion 14 of the housing 11, that is, the self-holding solenoid 20 exhibits a magnetic force that cancels the attractive magnetic force due to leakage current. The rod is released so that when it exceeds a certain value, the suction holding of the plunger 19 is released, and when the plunger 19 and the display unit 18 attached thereto are dropped by their own weight, the rod contacts the movable piece 35. 27 and 28 and a pair of fixed pieces 36 and 37 attached so as to be in contact with the conductive rods 23 and 24 of the rods 27 and 28 and a movable piece 35 attached to the display unit 18. Is configured. In this way, the short circuit 48 is formed by a simple mechanism including the movable piece 35 and the pair of fixed pieces 36 and 37.

  In the driving circuit 47 described above, the discharge gap 49 for absorbing a relatively large surge, the varistor 50 for absorbing a relatively small surge, and the surge absorber 51 for protecting the rectifier circuit 46 from these surges are provided on the charging side terminal 21. And the ground side terminal 22. In addition, protective resistors 52 and 53 are connected in series between the power application side terminal 21 and the ground side terminal 22 and the rectifier circuit 46.

  An operation example of the deterioration indicator 1 having the above configuration will be described in detail below. In the deterioration indicator 1, in a normal state, as shown in FIG. 1, the self-holding solenoid 20 attracts the plunger 19 with a magnetic force, thereby arranging the display portion 18 in the central portion 13 of the housing 11. Since the central portion 13 of the housing 11 is covered with a cover 15 (see FIGS. 4 and 5), it is in a non-display state.

  Here, since the deterioration indicator 1 is attached to a high place in the vicinity of the lightning arrester 3 of the transmission / distribution line 2, an impact may be applied to the housing 11 due to falling snow on the cover 15, a gust of wind, or birds. is there. Even when such an impact is applied to the housing 11, the impact is remarkably relieved by the buffer function of the L-shaped bracket 40, so that the self-holding solenoid 20 can be prevented from vibrating due to the impact. Accordingly, it is possible to reliably avoid a malfunction in which the plunger 19 of the self-holding solenoid 20 is released by suction due to vibration caused by an impact and the display unit 18 falls from the non-display state to the display state.

  On the other hand, when the lightning arrester 3 is deteriorated, a leakage current flows through the grounding wire 4 due to the deterioration of the lightning arrester 3, so that the deterioration indicator 1 has a detection resistor connected between the charging side terminal 21 and the grounding side terminal 22. The leakage current flowing through 45 is detected (see FIG. 6). The voltage between both terminals of the detection resistor 45 generated by this leakage current is rectified by the rectifier circuit 46, and the self-holding solenoid 20 is driven based on the output of the rectifier circuit 46. When the leakage current increases and exceeds a certain value, the self-holding solenoid 20 generates a magnetic force that substantially cancels the attractive magnetic force of the plunger 19 and releases the plunger 19.

  By releasing the suction of the plunger 19, as shown in FIG. 2, the display unit 18 falls by its own weight and is disposed on the lower part 14 of the housing 11. In this way, the display unit 18 is shifted from the non-display state to the display state. That is, since the lower portion 14 of the housing 11 is transparent and not covered with the cover 15, the display portion 18 is in a display state that can be viewed from the outside of the housing 11. Since the deterioration indicator 1 is normally attached to a high place in the vicinity of the lightning arrester 3 installed on the upper part of a utility pole or the like, it becomes easy to visually observe the transparent lower part 14 of the housing 11 from below 360 °. This makes it easy to recognize the display unit 18 in the display state.

  As described above, a display state in which the display unit 18 is located in the lower portion 14 of the housing 11, that is, the self-holding solenoid 20 causes a magnetic force that substantially cancels the attractive magnetic force due to a leakage current exceeding a certain value. When the suction of the plunger 19 is released, the movable piece 35 of the display unit 18 comes into contact with the fixed pieces 36 and 37 of the rods 27 and 28. The movable piece 35 connects the pair of fixed pieces 36 and 37 to form a short circuit 48. That is, when the movable piece 35 comes into contact with the pair of fixed pieces 36 and 37, the charging side terminal 21-conductive bar 23-fixed piece 36-movable piece 35-fixed piece 37-conductive bar 24-ground side terminal. 22 short circuits 48 are formed.

  Since the leakage current flows through the short circuit 48, it can be avoided that the leakage current continues to flow through the self-holding solenoid 20, so that the self-holding solenoid 20 can be prevented from being damaged and protected. In addition, since a self-holding solenoid that eliminates the holding state of the plunger with a relatively small current has been put to practical use, a detection resistor 45 having a relatively small resistance value can be used, and a grounding resistance thereby can be used. Can be suppressed.

  Further, the magnet 34 provided in the display unit 18 is attracted to the support plate 29 made of a ferromagnetic metal, so that the movable piece 35 comes into contact with the fixed pieces 36 and 37 in a tight contact state. Thereby, in the short circuit 48, the contact resistance between the movable piece 35 and the fixed pieces 36 and 37 can be suppressed low, and the short circuit state can be ensured.

  As described above, in accordance with the display of the deterioration state of the lightning arrester 3 by the deterioration indicator 1, the procedure for returning the deterioration indicator 1 to the normal state after replacing the lightning arrester 3 is as follows. . As shown in FIGS. 7 and 8, a jig 55 having a magnet 54 having the same polarity as the magnet 34 provided on the display unit 18 is attached to the display unit 18 in the display state from the outside of the housing 11. The display unit 18 is shifted from the display state to the non-display state by the magnetic repulsive force of both the magnets 34 and 54 by being close to 18.

  The dedicated jig 55 for returning the deterioration indicator 1 to the normal state is formed with an opening recess 56 in which the lower part 14 of the housing 11 of the deterioration indicator 1 can be accommodated, and the bottom of the recess 56 has the display portion 18. A jig body 57 having a magnet 54 having the same polarity as the magnet 34 is provided. In addition, the jig 55 is an indirect live line in which a long operation rod 58 is connected to the lower part of the jig body 57 so that the deterioration indicator 1 installed at a high place such as a utility pole can be operated. It is a tool.

  In the display state where the display unit 18 is disposed on the lower part 14 of the housing 11, the jig body 57 at the tip of the operation rod 58 is fitted into the lower part 14 of the housing 11 so as to be covered. With the magnetic repulsive force between the magnet 54 of the concave portion 56 and the magnet 34 of the display portion 18 having the same polarity, the display portion 18 rises from the lower portion 14 of the housing 11 to the central portion 13 (see arrow in FIG. 8). At this time, since the hole 38 is formed in the support plate 29 interposed between the magnet 54 of the jig 55 and the magnet 34 of the display unit 18, the magnetic repulsive force easily acts on the display unit 18. Yes. As the display portion 18 moves up, the plunger 19 is inserted into the inside 42 of the self-holding solenoid 20 and is attracted by the magnetic force, and the state of being located at the central portion 13 of the housing 11 is maintained (see FIG. 1). The display unit 18 is hidden by the cover 15 to be in a non-display state, and thus the deterioration indicator 1 is returned to the normal state.

  In this way, the display unit 18 is shifted from the display state to the non-display state at the lightning arrester replacement work site from the outside of the housing 11 by a simple operation using the dedicated jig 55 without disassembling the deterioration indicator 1. Thus, the normal state can be restored very easily, and the deterioration indicator 1 can be used repeatedly.

  In the above embodiment, the case where the L-shaped bracket 40 is used as an elastic member for attaching the self-holding solenoid 20 has been described. However, the present invention is not limited to this, and FIG. 9 or FIG. As shown, the structure may be elastically supported.

  The structure shown in FIG. 9 is such that the self-holding solenoid 20 is fixed to the tip of a flat metal plate 59 made of, for example, phosphor bronze with an insulating material 60 interposed therebetween. Further, in the structure shown in FIG. 10, a coating 62 having an insulating property is formed on the lower surface of a flat metal fitting 61 made of, for example, phosphor bronze, and the self-holding solenoid 20 is fixed through the coating 62. It is. The base ends of the flat metal fittings 59 and 61 are fixed to the rod 27 on the power application side or the rod 28 on the ground side.

  In any structure, when an impact is applied to the housing 11, the shock is absorbed by the shock absorbing function of the flat metal fittings 59, 61, thereby suppressing the self-holding solenoid 20 from vibrating due to the impact. Thereby, it is possible to reliably avoid a malfunction in which the plunger 19 of the self-holding solenoid 20 is released by suction due to vibration caused by an impact and the display unit 18 shifts from the non-display state to the display state.

  The present invention is not limited to the above-described embodiments, and can of course be implemented in various forms without departing from the gist of the present invention. It includes the equivalent meanings recited in the claims and the equivalents recited in the claims, and all modifications within the scope.

1 Degradation indicator 2 Power transmission / distribution line 3 Power distribution equipment (surge arrester)
DESCRIPTION OF SYMBOLS 4 Grounding wire 11 Housing 12 Upper part of housing 13 Central part of housing 14 Lower part of housing 18 Display part 19 Plunger 20 Self-holding type solenoid 21 Electric side terminal 22 Grounding side terminal 34 Magnet 35 Conductive movable piece 36, 37 Conductive fixed Piece (contact)
40 Elastic member (L-shaped bracket)
45 Detection resistor 46 Rectifier circuit 47 Drive circuit 48 Short circuit 54 Magnet 55 Jig

Claims (6)

A deterioration indicator that is connected to a ground wire of a power distribution material installed in a transmission / distribution line facility, detects a leakage current flowing through the ground wire due to deterioration of the power distribution material, and displays the deterioration of the power distribution material,
A display unit housed in a housing that can be shifted between a display state and a non-display state according to deterioration of the electrical distribution material, and a plunger that is housed in the housing and attached to the display unit is attracted by a magnetic force. A self-holding solenoid that brings the display unit into a non-display state, causes a magnetic force that substantially cancels the attractive magnetic force due to the leakage current, and releases the plunger to bring the display unit into a display state. With
The display unit is displayed with a magnetic repulsive force appearing between the two magnets by bringing a jig having a magnet of the same polarity as the magnet provided in the display unit close to the display unit in the display state from the outside of the housing. A deterioration indicator characterized in that a transition is made from a state to a non-display state.   The housing is formed of a cylindrical member having a transparent at least in the lower part, the self-holding solenoid is arranged in the central part of the housing, and the display part is arranged to be movable between the central part and the lower part of the housing. The deterioration indicator according to claim 1, wherein the display portion in the display state is visible at a lower portion of the housing.   The deterioration indicator according to claim 1, wherein the self-holding solenoid is attached to a fixed portion in the housing via an elastic member.   The self-holding solenoid rectifies the both-end voltage generated by the leakage current flowing in the detection resistor connected between the charging side terminal and the ground side terminal by a rectifier circuit, and sucks it based on the output of the rectifier circuit The deterioration indicator as described in any one of Claims 1-3 provided with the drive circuit which reveals the magnetic force which substantially cancels a magnetic force.   The drive circuit has contacts respectively connected to both terminals of the detection resistor between the power application side terminal and the ground side terminal, and generates a magnetic force that substantially cancels the attractive magnetic force by the leakage current. The deterioration indicator according to claim 4, further comprising a short-circuit that electrically closes the contact when the plunger is released from suction. The short circuit is fixedly disposed in the housing, and is attached to a pair of conductive fixing pieces provided between the power-applying side terminal and the grounding side terminal, and a display unit provided to be movable in the housing. is a conductive movable piece that connects the pair of conductive fixing pieces are made to appear the magnetic forces substantially cancel contact with the conductive fixing piece at the time of releasing suction of the plunger suction force by the leakage current The deterioration indicator according to claim 5, comprising: