JP4569014B2 - Electricity meter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for monitoring a sealed state of a terminal portion after watt-hour meter installation / wiring of a watt-hour meter used for electricity bill transactions is completed.
[0002]
[Prior art]
FIG. 6 is an external view of a conventional watt-hour meter for trading electric charges. In the figure, 1 is a watt-hour meter body, 2 is a cover, and 3 is a base, which form a housing that houses a watt-hour metering element. 4 is a terminal part. 5 is a terminal cover, 5a is a sealing projection protruding from the surface of the terminal cover 5, 6 is a sealing screw provided with a horizontal sealing hole 6a on the head, 7 is a sealing wire, 8 is a seal made of lead, etc. A ball 9 is a metering display, and displays a numerical value so that the amount of power measured by the power metering element can be visually recognized.
[0003]
In such a watt-hour meter 1, after the installation and wiring are completed, the terminal portion 4 is covered with the terminal cover 5, the sealing screw 6 is tightened, and the sealing wire 7 is inserted into the sealing hole 6 a, the sealing protrusion 5 a and the hole of the sealing ball 8. They are bound and sealed so that the sealing ball 8 is crushed and the sealing screw 6 cannot be turned freely. If the terminal cover 5 is removed by loosing the sealing screw 6 for the purpose of fraud such as theft, and the terminal part 4 is crafted, the sealing is destroyed. Thereby, it is detected that an illegal act has been performed on the terminal portion 4.
[0004]
[Problems to be solved by the invention]
In the sealing of the conventional watt-hour meter as described above, since humans need to regularly check the sealing state, a large amount of manpower is required for the patrol check. In addition, there is a drawback that it takes time to discover an illegal act after it has been performed. Furthermore, when the camouflage is resealed, there is a problem that it is difficult to find fraud.
[0005]
The present invention has been made to solve the above-described problems, and provides a watt-hour meter that can quickly detect that an illegal act such as theft of electricity to the terminal portion 4 has been performed.
[0006]
[Means for Solving the Problems]
The watt-hour meter according to the present invention includes a sealing screw in which the length of a screw portion for attaching the terminal cover to the terminal portion is L and the diameter of the lower neck portion is smaller than the screw diameter, and a lock nut that receives the screwing of the sealing screw And a detection nut that is electrically insulated from the locking nut and spaced apart by a distance D, and the detection nut and the sealing screw are inserted in the sealing screw in the sealing nut in the sealing nut and the detection nut and sealing screw are non-contact D <L And a switching circuit that operates when detecting electrical continuity between the lock nut and the detection nut and reports an abnormality to the outside from the communication means via the communication line.
[0007]
Further, the switching circuit is constituted by a thyristor.
[0008]
And a plurality of sensor means for monitoring the position change of the heads of at least two sealing screws each having the terminal cover attached to the terminal part, and a communication line when the sensor means detects the position change of the heads of the sealing screws. A communication means for reporting an abnormality to the outside via an alarm means for ignoring a short time position change of one sensor means, and an alarm means for outputting a warning when a plurality of sensor means detect a position change of the head of the sealing screw; It is equipped with.
[0010]
In addition, an alarm means for notifying the outside from the communication means via the communication line and outputting a warning is provided.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
FIG. 1 is a block diagram of a watt-hour meter according to Embodiment 1 of the present invention, FIG. 2 is a diagram showing a sealing screw state for explaining the operation of Embodiment 1, and (a) is a state in which the sealing screw is tightened, (B) shows a state in which the sealing screw is loosened.
In the figure, 1 to 9 are the same as those described in the prior art. Reference numeral 10 denotes an electronic electric energy metering element composed of a known induction type or electronic circuit multiplication circuit, etc., and displays a numerical value on the metering display unit 9 so that the electric energy metered by the power metering element 10 can be visually recognized. . Reference numeral 11 denotes a set nut to which the sealing screw 6 is screwed, which is made of a conductive metal and connected to the base 3 with ground. This ground connection can be easily made by spot welding the stop nut 11 to the base 3.
Reference numeral 12 denotes a detection nut made of a conductive metal, and is arranged at a position insulated from the stop nut 11 with a gap D. The sealing screw 6 is inserted into the screw portion of the detection nut 12 and is screwed to the locking nut 11. As shown in the drawing, the lower part 6c of the sealing screw 6 becomes thinner, and when the sealing screw 6 is tightened, the retaining washer 6b and the screw part of the detection nut 12 are located in this part. Neck lower portion 6c of the sealing screw 6 narrowed in tightened state of sealing screws 6 so as not to contact with the detection nut 1 2.
[0012]
Reference numeral 13 denotes a photocoupler, the light emission side of which is connected from the control power supply 14 to one end of the detection nut 12, and the output side of the photocoupler 13 is connected to the gate terminal of the switching element 15. The photocoupler 13 and the switching element 15 form a switching circuit and are appropriately provided with resistors and capacitors so that the operating potential is appropriate.
Reference numeral 16 denotes a reset switch for stopping the conduction of the switching element 15. Reference numeral 17 denotes an abnormality notification unit, which causes the alarm means 18 to issue an alarm such as blinking of an abnormal display or a buzzer sound in response to the conduction of the switching element 15. Reference numeral 19 denotes a communication interface (communication I / F), which transmits and receives a measurement value and the like at the electric energy metering element 10 by exchanging communication telegrams with an external central device via a communication line for remote automatic meter reading. Also, an abnormality report from the abnormality reporting unit 17 is reported to the central device via a communication line. Then, it is possible to release the abnormality reporting state by instantaneously opening the reset switch 16 and stopping the conduction of the switching element 15 according to an instruction from the central device.
[0013]
The relationship between the sealing screw 6, the set nut 11 and the detection nut 12 will be described with reference to FIG. The sealing screw 6 is made of a conductive metal and has a screw portion outer diameter φ1, a length L of the screw portion 6d, and a small diameter φ2 of the neck lower portion 6c. An inner diameter .phi.3 detection nut 12 sealing screw 6 is inserted, the lock nut 11 and the detection nut 12 is disposed at an interval D, the relationship is D <L, configured φ2 <φ3 <φ1. To increase the gap between the non-contact time with the small diameter φ2 of the neck lower portion 6c of the inner diameter φ3 seal screw 6 of the detection nut 12, the detection nut 12 is vertically screws in the large tap pilot hole. When the sealing screw 6 is tightened at the time of performing sealing, the sealing screw 6 is first threaded through the screw of the detection nut 12 and then tightened to the lock nut 11. When the sealing is completed, the detection nut 12 and the sealing screw 6 are disconnected from each other at the gap.
[0014]
Next, when the sealing screw 6 is loosened for the purpose of opening the terminal cover 5, the relationship between the length L of the screw portion 6d of the sealing screw 6 and the distance D between the lock nut 11 and the detection nut 12 is D <L. Therefore, the screw portion 6d of the sealing screw 6 is screwed to both the lock nut 11 and the detection nut 12 to enable electrical conduction. As a result, the light emission side of the photocoupler 13 is energized, a trigger signal is applied from the output side to the gate terminal of the switching element 15, the switching element 15 is turned on, and the abnormality reporting unit 17 is connected to the center via the communication I / F 19. An alarm is issued from the alarm means 18 at the same time that an abnormality is reported to the apparatus. In the central device, the dispatch of an investigator is instructed to the installation location of the watt hour meter from the ID number of the watt hour meter assigned to each unit for automatic meter reading. Since the alarm continues until the investigator arrives at the site, the alarm means 18 may be provided with a timer to stop the alarm after a certain time.
[0015]
FIG. 3 is a diagram illustrating another configuration of the switching circuit according to the first embodiment. In the figure, 6, 11, 12, 14 to 19 are the same as described above. In the above embodiment, since the detection power source and the control power source are separate power sources and the lock nut 11 is welded to the base 3, the photocoupler 13 is interposed to secure the bias potential of the switching element 15. As shown, the same operation can be performed even if the gate terminal of the switching element 15 is directly connected to the lock nut 11 without grounding the lock nut 11.
[0016]
Although the switching element 15 can be constituted by a switching relay or a transistor, a thyristor is used in the present invention. Once the thyristor is turned on, the sealing screw 6 starts to be loosened by utilizing the property that energization can be continued even if the gate is turned off, and the screw portion 6d of the sealing screw 6 comes into contact with the detection nut 12 and is surprised by the alarm. The alarm can be continued even if 6 is retightened, and the camouflaged reseal is not overlooked.
[0017]
Embodiment 2. FIG.
FIG. 4 is a block diagram of the watt-hour meter according to the second embodiment of the present invention, and FIG. 5 is a process flowchart for performing obstacle detection of the watt-hour meter according to the second embodiment. In the figure, 1 to 10 and 17 to 19 are the same as those described in the first embodiment.
In order to simplify the drawing, the sealing line 7 and the sealing ball 8 are omitted in FIG.
Reference numeral 20 denotes a CPU, which controls the communication I / F 19 and performs arithmetic processing control when the power metering element 9 is an electronic type. A plurality of photo interrupters 21 are provided so as to individually monitor the plurality of sealing screws 6. The photo interrupter 21 is composed of an infrared light emitting portion 21a and an infrared light receiving portion 21b with the head of each tightened sealing screw 6 as a focal position A, and is a see-through provided in the cover 2 disposed in the casing of the electric energy. The focal position A is monitored through the window 2a. Reference numeral 22 denotes a sensor that detects a signal change of the infrared light receiving unit 21b, and reference numeral 23 denotes an abnormality determination unit that determines abnormality from the signal change of the sensor 22. When the abnormality determining unit 23 determines that an abnormality has occurred, the abnormality notifying unit 24 issues an alarm to the central device via the communication I / F 19 and at the same time issues an alarm from the alarm means 18.
[0018]
The relationship of the output signal of the photo interrupter 21 is, for example, that the infrared light emitted from the infrared light emitting unit 21a passes when there is no obstacle at the focal position A, and the infrared light receiving unit 21b does not obtain reflected light. L ”. When there is an obstacle such as a human hand or a screwdriver that rotates the sealing screw 6 at the focal position A, the infrared light receiving unit 21b sets the output signal when detecting reflected light to “H”. The sensor 22 monitors the signals of both infrared light receiving units 21b, and on the other hand, if the signal of the infrared light receiving unit 21b becomes “H”, it measures the time from that point to “L”. For example, when an insect or the like flies at the focal position A, a short-time signal “H” is prevented from being erroneously detected, a shielding object is intentionally attached to the fluoroscopic window 2a, or a seal on one side is broken. This is a measure for determining this.
[0019]
Next, the determination process of the abnormality determination unit will be described with reference to the flowchart of FIG. When the sensor 22 detects a reflected signal in any one of the infrared light receivers 21b, the time duration T of the signal “H” is measured from this time by the time counter (steps S1 and S2). When the duration “T” of the signal “H” is less than a predetermined time t1 (for example, 2 seconds), it is determined that the insect does not fly or the person does not intend to release the seal, and the time counter is cleared and the original monitoring is performed. Return to the state (steps S3 and S4). When the duration “T” of the signal “H” is equal to or longer than the predetermined time t1, it is considered that there is an obstacle on the head of the sealing screw 6 or the sealing screw 6 is loosened and is lifted from the tightened state. This is because the retaining washer 6b is engaged with the lower part of the neck of the sealing screw 6 and held so that the sealing screw 6 does not fall off the terminal cover 5 as shown in FIG.
[0020]
When the signal of one infrared light receiving unit 21b is “H” and the signal of the other infrared light receiving unit 21b is also “H”, the sensor 22 indicates that an illegal act has been performed on the head of the sealing screw 6. Therefore, an alarm is issued from the alarm means 18 via the abnormality reporting unit 17, and at the same time, an abnormality is reported to the central device via the communication I / F 19 (steps S5, S6, S8).
[0021]
When the “H” signal continues to only one of the infrared light receiving portions 21b for a long time, there is a possibility that a shield is attached to the photo interrupter 21 or the seal on one side is broken. When only one “H” signal continues for 24 hours) or more, the dispatch number of the investigator is instructed from the watt-hour meter ID number to the installation location of the watt-hour meter (steps S7 and S8).
[0022]
Such sealing screw monitoring by infrared rays is versatile because it does not require a specially shaped sealing screw.
[0023]
【The invention's effect】
Since the present invention is configured as described above, it is possible to reliably detect that an illegal act such as theft of electric power has been performed on the terminal portion, and to quickly detect an abnormality report through a communication line for automatic meter reading. it can.
[Brief description of the drawings]
FIG. 1 is a block diagram of a watt-hour meter according to a first embodiment of the present invention.
FIG. 2 is a diagram showing a sealing screw state for explaining the operation of the first embodiment.
FIG. 3 is a diagram illustrating another configuration of the switching circuit according to the first embodiment;
FIG. 4 is a block diagram of a watt-hour meter according to Embodiment 2 of the present invention.
FIG. 5 is a flowchart of an obstacle detection process of the watt-hour meter according to the second embodiment.
FIG. 6 is an external view of a conventional electricity meter for electricity bill trading.
[Explanation of symbols]
2a see-through window, 4 terminal section, 5 terminal cover 5a sealing projection, 6 sealing screw, 6a sealing hole 6b retaining washer, 6c lower neck, 6d screw section 7 sealing wire, 8 sealing ball, 9 measuring display section 10 electric energy Weighing element 11 Stop nut 12 Detection nut 13 Photocoupler 15 Switching element 16 Reset switch 17 Abnormality reporting unit 18 Alarm means 19 Communication I / F, 20 CPU, 21 Photo interrupter 21a Infrared light emitting unit, 21b Infrared light receiving unit 22 Sensor 23 Abnormality determination unit

Claims (4)

  In a watt-hour meter for power trading in which a terminal part is sealed with a sealing screw, the terminal cover that covers the terminal part, and the length of the screw part to which the terminal cover is attached by screwing are L, and the diameter of the lower part of the neck is a screw. The sealing screw made of a conductive metal having a diameter smaller than the diameter, a locking nut made of a conductive metal that receives the screwing of the sealing screw, and the locking nut are electrically insulated and spaced apart from each other in the terminal cover direction. The detection nut provided and the female screw of the detection nut in the sealed state are inserted through the lower part of the neck of the seal screw, and the detection nut and the seal screw are not in contact with each other and the distance D <screw length L. A switching circuit that operates when electrical continuity between the lock nut and the detection nut is detected, and a communication means that receives the operation of the switching circuit and reports an abnormality to the outside via a communication line are provided. Electricity meter, characterized in that the.   The watt-hour meter according to claim 1, wherein the switching circuit is constituted by a thyristor. In a watt-hour meter for power trading in which a terminal part is sealed with a sealing screw, the terminal cover that covers the terminal part and the position change of the heads of at least two sealing screws to which the terminal cover is attached are respectively infrared-monitored. A plurality of sensor means, a communication means for notifying the outside via a communication line when the sensor means detects a position change of the head of the sealing screw, and a short time position change of one sensor means An watt hour meter characterized by comprising: alarm means for outputting a warning when the plurality of sensor means detect a change in the position of the head of the sealing screw . Energy meter according to any one of claims 1 to 3 any one, characterized in that a alarm means for warning output as well as abnormality notification to the outside from the communication means.

Images