JP6339377B2 - Plug-in connection unit - Google Patents

Description

  The present invention relates to a plug connection unit connected to an outlet with a grounding pole provided with a plug receptacle, and more particularly, a circuit breaker on an electric circuit to which the grounding outlet is connected by detecting a shake due to an earthquake. It is related with the plug-in connection unit provided with the function to operate.

  Conventionally, various plug connection units having a function of operating a circuit breaker on an electric circuit connected to an outlet by detecting a shake due to an earthquake have been disclosed.

  For example, an example disclosed in Patent Document 1 will be described with reference to FIG. The plug connection unit shown in FIG. 4 is configured as an outlet plug 2 connected to the bus bar 1 of the low-voltage power supply and an intermediate outlet plug 3 connected to the outlet plug 4. An electric leakage breaker 11 as the circuit breaker is disposed on the bus 1, and the outlet tap 2 is disposed at an appropriate location indoors via a branch breaker 12. The outlet tap 2 is provided with insertion electrode receptacles 21 and 21 and an insertion ground electrode receptacle 22, and the insertion earth electrode receptacle 22 is grounded.

  The intermediate outlet plug 3 is provided with an abnormality detector 35 for detecting a shake due to an earthquake as an abnormal situation. When the abnormality detector 35 detects the shake, an electric signal is sent to the switch unit 37 of the ground fault generating circuit. Is output. And this switch part 37 act | operates and a weak ground fault electric current is generated between the electric power feeding circuit provided with the insertion electrode receiving metal fitting, and the earthing circuit provided with the insertion earth electrode receiving metal fitting. As a result, an unbalanced current on the electric circuit generated in the electric circuit is detected by the earth leakage breaker 11 disposed in the bus 1, and the circuit breaker is activated to interrupt the entire electric circuit.

  As described above, in Patent Document 1, an intermediate outlet plug 3 including an abnormality detector 35 and the like in an arbitrary outlet tap 2 that is normally arranged in a power feeding circuit including a leakage breaker 11 that has been conventionally used. Without any special installation work, by detecting an abnormality such as an earthquake in a desired location and operating the earth leakage breaker 11 to cut off the current of the electric circuit and prevent an electric fire. To prevent.

An example disclosed in Patent Document 2 will be described with reference to FIG. The plug-in connection unit described in FIG. 5 is configured as an outlet plug 10 that is connected to an outlet tap 26 that leads to a bus 24 of a low-voltage power supply, as in Patent Document 1. The case 12 constituting the plug-in connection unit is provided with a leakage generating part. When a shake due to an earthquake is detected, the leakage generating part is activated to generate an unbalanced current in the indoor commercial power line. The earth leakage breaker normally installed in the house is activated to cut off the power to the house. As described above, even in Patent Document 2, when an abnormality such as an earthquake is detected without requiring any special installation work, the earth leakage breaker to which the outlet circuit is connected is activated to cut off the current of the electric circuit. To prevent electrical fires.

   When an earthquake is detected, the outlet plug type plug-in connection unit that operates the circuit breaker to shut off the current by generating a leakage current on the electric circuit requires special installation work for its introduction. It is very convenient because it can be introduced without having to do so.

On the other hand, in order for the plug-in connection unit to generate a leakage current and cause the leakage breaker on the electric circuit to perform a leakage operation, the grounding system serving as a leakage current path needs to function normally.

  That is, taking a general single-phase three-wire electric circuit as an example, the secondary winding neutral wire side of the transformer interposed on the primary side of the electric circuit is grounded by the first electrical terminal provided on the ground ( In addition, the ground line is grounded by the second electrical terminal provided on the ground via the concentrated ground terminal (class D ground) in the load side electric circuit of the transformer. It is necessary to be kept below a predetermined ground resistance value described later.

  The predetermined ground resistance value is as described in “Technical Standards for Electrical Equipment” established for grounding work. According to Article 19 of the interpretation of technical standards, “ Insulation of electric circuit] When grounding the items listed in No. 6 and No. 7 b, Article 23 [Grounding of the service area inlet], Article 28 [Electrical equipment grounding] Paragraphs 1, 2 and Article 4 and Article 42 [Grounding of Lightning Arrester] When grounded in accordance with the provisions of No. 2 and No. 3a and b, and when grounded to the part of the low-voltage overhead wire installed on the same support as the extra high-voltage overhead wire Except when performing construction, the following four types are listed in the left column, and the grounding resistance value in each grounding work is less than or equal to the value listed in the right column of the table according to the type of grounding work listed in the left column of the same table. According to the type of grounding work. In the case of Class A grounding work, the grounding resistance value is 10Ω, and in the case of Class B grounding work, the amperage of the 1-wire ground fault current of the high-voltage side or extra high-voltage side of the transformer is 150 (the transformer If the ground voltage of the low piezoelectric circuit exceeds 150 V due to the contact between the high voltage circuit or the special high voltage circuit whose working voltage is 35,000 V or less and the low voltage circuit, it will automatically exceed 1 second and within 2 seconds. When a device that cuts off a high voltage path or a special high voltage path whose operating voltage is 35,000V or less is provided in 300, a device that automatically shuts off a high voltage path or a special high voltage path whose working voltage is 35,000V or less within 1 second In the case of Class C grounding work, 10 ohms (in the case of grounding on a low piezoelectric circuit, the circuit is automatically generated within 0.5 seconds. When installing a device to shut off 500 Ω), 100 Ω for Class D grounding work (500 Ω when installing a device that automatically shuts off the electric circuit within 0.5 seconds when the electric circuit is grounded on a low piezoelectric circuit) The ground resistance value is determined.

  In large buildings such as buildings, there are many cases where the grounding of the transformer for receiving power at high voltage and converting it to low voltage is common with the grounding on the load side, in which case the grounding resistance of the grounding wire is very low The grounding system is considered to function well. In addition, as a method of domestic wiring equipment, the introduction of a method of drawing a dedicated grounding wire from the grounding point on the power source side to the end, called the TN method in IEC standards, has been attempted. Resistance is also considered to be functioning. On the other hand, in the grounding method called the TT method that is often constructed in general detached houses, the grounding resistance at the end portion is likely to change depending on the grounding work, and may become high resistance. is there.

  If the grounding resistance is high, there is a risk of electric shock and electrical safety may not be ensured. Generally, however, the insulation of the load equipment installed in the electric circuit deteriorates, and the ground and the housing of the load equipment Even when the ground voltage Vg is generated, the ground resistance that does not affect the human body is obtained as follows.

  When RB is a class B ground resistance, RD is a class D ground resistance, and VE is an electric circuit voltage, Vg = {RD / (RB + RD)} VE (Formula 1). Here, assuming that the resistance of the human body is 1 kΩ and the allowable current passing through the human body is 30 mA, which is limited to several minutes (electric shock current by Mr. Biegelmeier and the physiological response of the human body), Vg = 30 V is allowable as the ground voltage. Is considered the upper limit.

  And when the voltage VE of the electric circuit is 200V, by substituting Vg into Equation 1 and calculating, RB = 5.7RD (Equation 2), and the size of the class B grounding resistance is 10Ω RD≈1.7Ω, so that the D-type grounding resistance should be set to about 1.7Ω or less.

  However, the ground resistance of 1.7Ω or less is a low ground resistance value that is practically difficult to obtain by ordinary grounding work. When grounding, it is necessary to devise a technique for reducing the grounding resistance by applying a scientific treatment to the soil and using, for example, a grounding resistance reducing agent using an inorganic high water content crystal.

  Furthermore, it is necessary to maintain this low ground resistance over time. To that end, it is necessary to confirm whether the ground resistance is maintained over time in the future. The environment often changes from the state at the time of the grounding work due to improvements in the surrounding area, etc., and it is difficult to check the grounding resistance value each time because it is difficult in practice. Met. In many cases, it has not been confirmed what the grounding resistance value is after several years to several decades after grounding.

JP 9-327119 A JP-A-9-147728

  In this way, in order for the plug connection unit to generate a leakage current and cause the leakage breaker on the electric circuit to perform a leakage operation, the grounding system that is the path of the leakage current is kept below a predetermined resistance value and functions normally. However, if the ground resistance value is high, if an earthquake occurs after installing the plug connection unit in the outlet, even if a leakage current is generated from the plug connection unit, There is a problem in that a leakage current that causes the leakage breaker to perform a leakage operation does not flow, and the leakage breaker cannot be operated.

  That is, even though the power supply is supplied to the plug-in connection unit itself, the generated leakage current as an unbalanced current does not flow to the ground circuit on the electric circuit, and the leakage breaker There is a problem that a situation in which the operation of the system is not performed may occur.

  The present invention has been made in view of such points, and the object of the present invention is to determine whether or not the grounding system is functioning normally in an outlet to which the plug-in connection unit is connected, and over time. An object of the present invention is to provide a plug-in connection unit having a function of confirming whether or not a grounding resistor is functioning normally.

  In order to solve the above-mentioned problem, in the present invention, a plug connection unit used by connecting to an outlet circuit having a voltage electrode (L electrode), a neutral electrode (N electrode), and a ground electrode (E electrode). A plug blade inserted corresponding to a plug receiver at each pole provided in the outlet, a power supply circuit that is electrically connected to the plug blade to obtain a driving power supply, and a power supply from the power supply circuit And a seismic sensor unit for detecting an oscillation caused by an earthquake and outputting an output signal, a current generating unit for passing a current between a neutral electrode and a ground electrode in the outlet circuit, and the neutral electrode A voltage measuring unit that measures a voltage between the grounding electrode and a ground resistance calculating unit that calculates a ground resistance from the current generated from the current generating unit and the voltage measured by the voltage measuring unit. Plug-in connection as a feature Those that provided the knit.

  According to the above configuration, since the ground resistance calculation unit that calculates the ground resistance from the current generated from the current generation unit and the voltage measured by the voltage measurement unit is provided, Whether or not the grounding system of the circuit is normal can be easily confirmed at the place.

  According to a second aspect of the present invention, the magnitude of the current output from the current generator is smaller than the operating sensitivity current of the earth leakage breaker installed upstream of the outlet circuit.

  According to the above configuration, when the ground resistance is calculated, it is possible to check whether the circuit ground system is normal by performing the calculation without operating the earth leakage circuit breaker. It is possible to avoid the circuit breakage due to the operation of the earth leakage circuit breaker.

  The third invention is characterized in that the magnitude of the current output from the current generator is larger than the operating sensitivity current of the leakage breaker installed upstream of the outlet circuit.

  According to the above configuration, since the calculation is performed with the operation of the earth leakage circuit breaker when calculating the ground resistance, it is possible to confirm whether the circuit grounding system is normal or not together with the actual interruption operation. .

The fourth invention is characterized in that the magnitude of the current outputted from the pre-SL current generator is output is variable.

According to the above configuration, for varying the magnitude of the current outputted from the current generation unit, it can be operated reliably earth leakage circuit breaker in accordance with the state of the grounding system of the circuit.

  According to a fifth aspect of the present invention, there is provided an iterative confirmation unit that causes a ground resistance calculation unit that calculates a ground resistance at predetermined time intervals to perform the calculation.

  According to the above configuration, the calculation for obtaining the ground resistance in the grounding system can be repeatedly performed at predetermined time intervals, the magnitude of the grounding resistance can be obtained over time, and the grounding system is normal. It can be confirmed whether or not it works.

  As described above, according to the present invention, in the outlet to which the plug-in connection unit is connected, whether the grounding system is functioning normally and whether the grounding resistance is functioning normally over time is determined. A plug-in connection unit having a function of checking can be provided.

It is the schematic of the electrical circuit where the plug-in connection unit which concerns on Embodiment 1 of this invention is applied. It is a block block diagram of the plug-in connection unit which concerns on Embodiment 1. FIG. It is a path | route diagram of the electric current output to an electric circuit from an insertion connection unit. It is a figure which shows the prior art example 1. FIG. It is a figure which shows the prior art example 2.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, description of the following preferable embodiment is only an illustration essentially, and does not restrict | limit this invention, its application thing, or its use.

In the electric circuit shown in the embodiment, the neutral wire side of the secondary winding of the transformer 2 interposed in the electric circuit is grounded by providing the first electrical terminal 21 on the ground (B-type grounding) A distribution board 1 is provided on the load side of the transformer, and is grounded (D-type grounding) by a second electrical terminal 104 provided on the ground via a centralized grounding terminal provided on the distribution board 1. An electric circuit having a grounding system.

  Also, in this application, as defined in JEAC 8001, the extension regulations of the Electricity Regulations published by the Japan Electric Association, the neutral wire is the electric wire connected to the neutral pole of the power source of the multi-wire circuit, A neutral wire or a grounded wire that is grounded according to technical needs in the electric circuit is called a grounded electric wire. For example, in a single-phase three-wire circuit, there are two voltage poles as voltage poles, that is, an L1 pole and an L2 pole, and an N pole as a neutral pole. In the single-phase two-wire circuit, there is a ground-side electric wire that is grounded to the voltage electrode. The grounding electrode is the E pole.

  In FIG. 1, 1 is a distribution board, 101 is a main circuit breaker which is a circuit breaker, and has a leakage detection function. A plurality of branch breakers 102 are connected to the load side of the main breaker 101. Reference numeral 103 denotes a centralized ground terminal for connecting a ground line connected to the ground and for connecting a ground line in the branch circuit.

  Reference numeral 105 denotes an outlet in the branch circuit. Normally, one of the L1 pole and the L2 pole, a neutral pole (N pole), and a ground pole (E pole) are connected to the outlet 105.

  3 is a plug-in connection unit. In FIG. 2, the plug connection unit 3 includes a plug blade 31 connected to the voltage pole (L1 pole, L2 pole), a plug blade 32 connected to the neutral pole (N pole), and a ground pole (E pole). Plug blades 33 to be connected, a power supply circuit 34 that is electrically connected to these plug blades to obtain drive power, and a power supply from the power supply circuit 34 to detect shaking due to an earthquake and output an output signal A seismic sensor unit 35, a signal processing unit 30 that receives an output signal from the seismic sensor unit 35 and performs signal processing, and receives an output signal from the signal processing unit 30, A current generator for generating a current between the ground electrode, a voltage measuring unit 37 for measuring a voltage between the neutral electrode and the ground electrode, and a current and a voltage measuring unit generated from the current generator. Calculate the ground resistance from the voltage measured by It is constituted by a ground resistance calculating unit. The ground resistance calculation unit is provided in the signal processing unit 30. The ground resistance value is calculated by the signal processing unit 30 and the content is displayed on the ground resistance display unit 39.

  The current generation unit 36 has a constant current generation circuit capable of changing the output current. The magnitude of the current generated from the current generation unit 36 is a normal value for calculating the ground resistance value in the ground system. 30 mA corresponding to the sensitivity of the earth leakage breaker installed in the house is output as a threshold value. First, a current (for example, 20 mA) smaller than 30 mA is generated between the neutral electrode and the ground electrode in the outlet circuit 105, and the voltage between the neutral electrode and the ground electrode is measured by the voltage measuring unit 37. As shown in FIG. 3, the current flows as indicated by the dotted arrow in the figure. The signal processing unit 30 calculates the ground resistance value from the magnitude of the current and the magnitude of the voltage.

  When the calculated ground resistance value is in the normal range, normal display is performed on the ground resistance display unit 39. When the calculated ground resistance value is in an abnormal range (for example, several KΩ to MΩ), the ground resistance display unit 39 displays an abnormality.

  In this case, when calculating the ground resistance, it is possible to check whether the grounding system of the circuit is normal by operating without operating the earth leakage circuit breaker. It is possible to avoid the circuit from power failure due to the operation.

  As another embodiment, a current (for example, 50 mA) larger than 30 mA corresponding to the sensitivity of a leakage breaker installed in a normal house is generated as the magnitude of the current generated from the current generator 36. In this case, in order to generate a current larger than the operating sensitivity current of the earth leakage breaker, the operation of the earth leakage breaker is accompanied when calculating the ground resistance. Both can be confirmed.

  Further, the current output from the current generator 39 may be varied and output. That is, the magnitude of the output current is changed stepwise or continuously from a small current (for example, 20 mA smaller than the operating sensitivity current of the earth leakage breaker) to a large (for example, 50 mA larger than the operating sensitivity current of the earth leakage breaker). Change the output. Thereby, while being able to obtain | require the grounding resistance value in a circuit, an earth-leakage circuit breaker can be actually operated and the state of a grounding system can be confirmed more reliably.

  Further, the signal processing unit 30 may be configured to include an iterative confirmation unit that causes the ground resistance calculation unit that calculates the ground resistance at predetermined time intervals to perform the calculation.

  The repetition confirmation unit is configured by using an electronic timer or a programmed microcomputer so that the series of determinations described above are periodically performed. Since the repetitive confirmation unit can confirm the connection state of the grounding system at predetermined time intervals, it is possible to easily confirm the ground resistance that changes over time. In addition, there is an accompanying effect that it is possible to confirm a decrease in functionality due to aging of various connection parts in the grounding system.

  In addition to the repetitive confirmation unit, a storage unit (for example, a memory inside the microcomputer or an external memory) that accumulates data such as the measured ground resistance value, voltage value, and ground state confirmation result over time is provided. If data such as ground resistance value, voltage value, ground state confirmation result, etc. is accumulated over time and the accumulated data can be called up and confirmed, the secular change of ground state can be confirmed or obtained each time. Various kinds of data can be used such as being able to be displayed on the ground resistance display unit 39.

  In addition to confirmation at a predetermined time interval, confirmation may be performed at a predetermined timing, for example, at the turn of the season, or when the user wants to confirm. In addition, a sensor for measuring a change in weather, temperature, and humidity may be provided, and confirmation may be performed when there is a predetermined change.

  A power storage unit 38 is connected to the power supply circuit 34 and the signal processing unit 30. When power supply from an electric power company or the like is stopped after the occurrence of an earthquake, the signal processing unit stores the fact that an earthquake has occurred for a certain period of time. The power storage unit 38 is configured using a capacitor, but may be configured using other primary batteries or secondary batteries.

  Reference numeral 40 denotes a test operation circuit. The test operation circuit 40 is configured by using an operation switch, and is connected to the signal processing unit 30. When the operation switch is operated, the switch circuit is closed, and an output signal is sent from the signal processing unit 30 to the current generation unit 36 to cause the outlet circuit 105 to generate a current.

  As described above, the plug-in connection unit 3 in the present application operates the earth leakage breaker by flowing a pseudo earth leakage current that is an unbalanced current through the circuit triggered by the occurrence of an earthquake. By providing the function of confirming whether or not the grounding system is normal, it is possible to provide a plug-in connection unit having excellent electrical safety.

  In addition, although the magnitude of the current generated from the current generator 36 is set to 30 mA as a threshold, in addition to this, for example, 15 mA, which is a common leakage sensitivity current in a branch switch, is used as a second threshold, You may provide the plug-in connection unit which interrupts | blocks the electric power feeding to a branch circuit with the operation | movement of an earth-leakage circuit breaker.

1 Distribution board 101 Main breaker 102 Branch breaker 103 Centralized grounding terminal 104 Second electrical terminal 105 Outlet 2 Transformer 21 First electrical terminal 3 Plug-in connection unit 30 Signal processing unit 31 Plug blade 32 of voltage pole Plug electrode 33 of ground electrode Plug blade 34 of ground electrode Power supply unit 35 Seismic sensor unit 36 Current generation unit 37 Voltage measurement unit 38 Power storage unit 39 Ground resistance display unit 40 Test operation unit

Claims (5)

A plug connection unit used by connecting to a power outlet circuit having a voltage electrode (L electrode), a neutral electrode (N electrode), and a ground electrode (E electrode),
A plug blade to be inserted in correspondence with the plug receptacle at each pole provided in the outlet;
A power supply circuit that is electrically connected to the plug blade to obtain a driving power supply;
A power source is supplied from the power supply circuit, has a seismic sensor unit that detects an oscillation due to an earthquake and outputs an output signal, and
A current generator for passing a current between a neutral electrode and a ground electrode in the outlet circuit;
A voltage measuring unit for measuring a voltage between the neutral electrode and the ground electrode;
A plug connection unit comprising a ground resistance calculation unit that calculates a ground resistance from a current generated from the current generation unit and a voltage measured by the voltage measurement unit. 2. The plug-in connection unit according to claim 1, wherein the magnitude of the current output from the current generator is smaller than the operating sensitivity current of an earth leakage breaker installed upstream of the outlet circuit. 2. The plug-in connection unit according to claim 1, wherein the magnitude of the current output from the current generator is larger than the operating sensitivity current of the leakage breaker installed upstream of the outlet circuit. Plug connection unit according to claim 2 or claim 3 wherein the magnitude of the current outputted from the pre-SL current generator is output is variable. 5. The plug-in according to claim 1, further comprising: a repetition confirmation unit that causes a ground resistance calculation unit that calculates a ground resistance to perform calculation at predetermined time intervals. Connection unit.

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