JP7061803B2 - Plug-in connection unit - Google Patents

Description

The present invention relates to a plug-in connection unit connected to an outlet with a grounding electrode provided with a plug receiver, and more specifically, a circuit breaker on an electric circuit to which the outlet with a grounding electrode is connected by detecting shaking due to an earthquake. It relates to a plug-in connection unit having a function of operating the above.

Conventionally, various plug-in connection units having a function of detecting shaking due to an earthquake and operating a circuit breaker on an electric circuit to which an outlet is connected have been disclosed.

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

The intermediate outlet plug 3 is provided with an abnormality detector 35 that detects shaking due to an earthquake as an abnormal situation, and when the abnormality detector 35 detects shaking, an electric signal is sent to the switch portion 37 of the ground fault generation circuit. It is output. Then, the switch portion 37 operates to generate a weak ground fault current between the feeding electric circuit provided with the plug-in electrode receiving metal fitting and the grounding electric circuit provided with the plug-in ground electrode receiving metal fitting. As a result, the earth leakage breaker 11 arranged on the bus 1 detects the unbalanced current on the electric circuit generated in the electric circuit, and the circuit breaker operates to cut off the current of the entire electric circuit.

As described above, in Patent Document 1, in the power supply circuit provided with the earth leakage breaker 11 conventionally used, the intermediate outlet plug 3 provided with an abnormality detector 35 or the like on an arbitrary outlet tap 2 normally arranged. By detecting an abnormality such as an earthquake at a desired location and operating the earth leakage breaker 11, the current of the electric circuit is cut off and an electric fire is prevented. It is prevented.

Further, 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 connected to an outlet tap 26 leading to a bus 24 of a low-voltage power supply, as in Patent Document 1. An earth leakage generating part is provided in the case 12 constituting the plug-in connection unit, and when shaking due to an earthquake is detected, the earth leakage generating part is activated to generate an unbalanced current in an indoor commercial electric wire, so that each house is equipped with an unbalanced current. Operate the earth leakage breaker normally installed in the house to cut off the power supply of the house. As described above, also in Patent Document 2, when an abnormality such as an earthquake is detected without requiring special installation work, the earth leakage breaker to which the outlet circuit is connected is operated to cut off the current of the electric circuit. This prevents electric fires.

The outlet plug type plug-in connection unit that activates the circuit breaker to cut off the current by generating a leakage current on the electric circuit when an earthquake is detected requires special installation work for its introduction. It is very convenient because it can be introduced without any trouble.

On the other hand, in order for the plug-in connection unit to generate an earth leakage current and cause the earth leakage breaker on the electric circuit to perform an earth leakage operation, it is necessary that the grounding system serving as the path of the earth leakage current is functioning normally.

That is, in the case of 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 electric terminal provided on the ground. In addition to being grounded in class B), the grounding wire is grounded (class D grounded) by a second electrical terminal provided on the ground via the centralized grounding terminal in the load side electric circuit of the transformer, and these grounded states are maintained. , It is necessary to keep it below the predetermined grounding resistance value described later.

The predetermined grounding resistance value is as described in the "Technical Standards for Electrical Equipment" stipulated for grounding work, and according to Article 19 of the Interpretation of Technical Standards, "Grounding work is Article 13 [ Insulation of electric wires] When grounding the items listed in items 6 and 7 (a), Article 23 [Grounding of the inlet of the demand place], Article 28 [Grounding of electrical equipment], Paragraphs 1 and 2 and Paragraph 4 and Article 42 [Grounding of lightning arrester] When grounding according to the provisions of items 2 (a) and (3) (a) and (b), and grounding to the part installed on the same support as the special high-voltage overhead wire of the low-voltage overhead wire. Except for the case of 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 same table according to the type of grounding work listed in the left column of the same table. Depending on the type of grounding work, the grounding resistance value is 10Ω in the case of class A grounding work, and the high voltage side of the transformer or special in the case of class B grounding work. The amperage of the one-line ground fault current of the high-voltage side electric line is 150 (the high-voltage side electric path of the transformer or the special high-voltage side electric path whose working voltage is 35,000 V or less and the low-voltage side electric path are mixed with each other to ground the low piezoelectric path. When the voltage exceeds 150V, it is automatically within 1 second and within 2 seconds. The number of ohms is equal to the value obtained by dividing the high piezoelectric path or the device for blocking the special high piezoelectric path with an operating voltage of 35,000 V or less (600). 500Ω when installing a device that automatically shuts off the electric line within 0.5 seconds when ground is generated in the electric line, 100Ω in the case of class D grounding work (in the low voltage path, in the electric line) When installing a device that automatically shuts off the electric wire within 0.5 seconds when ground is generated, the ground resistance value is set to 500Ω).

In large buildings such as buildings, the grounding of the transformer for receiving power at high voltage and converting it to low voltage is often shared with the grounding of the load side, in which case the grounding resistance of the grounding wire is very low. The grounding system is considered to be fully functional. In addition, as a method of wiring equipment in Japan, an attempt is being made to introduce a method called the TN method in which a dedicated grounding wire is routed from the grounding point on the power supply side to the end, and in that case, the grounding wire is grounded. It is believed that the resistance is also working. On the other hand, in the grounding method called the TT method, which is often used in general detached houses, the grounding resistance at the terminal part is likely to change depending on the grounding work, and there is a possibility that the resistance will be high. be.

If the grounding resistance becomes high, there is a risk of electric shock and electrical safety may not be ensured. Even when the voltage to ground Vg is generated, the grounding 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 the voltage of the electric circuit, Vg = {RD / (RB + RD)} VE ... (Equation 1) is shown. Here, assuming that the resistance of the human body is 1 kΩ and the allowable current for passing through the human body is 30 mA, which is limited to several minutes (electric shock current by Mr. Biegelmeier and the physiological reaction of the human body), Vg = 30 V is acceptable as the voltage to ground. Is considered the upper limit of.

Then, when the voltage VE of the electric circuit is 200V, by substituting Vg into Equation 1 and performing an operation, RB = 5.7RD ... (Equation 2), and the magnitude of the Class B grounding resistance is 10Ω. Since RD ≈ 1.7Ω, the D-class grounding resistance may be set to about 1.7Ω or less.

However, this grounding resistance of 1.7Ω or less is actually a low grounding resistance value that cannot be obtained by normal grounding work. It is necessary to apply scientific treatment to the soil when grounding, and to reduce the grounding resistance by using, for example, a grounding resistance reducing agent using an inorganic high water content crystal or the like.

Furthermore, it is necessary to maintain this low ground resistance over time, and for that purpose, it is necessary to confirm in the future whether the ground resistance is maintained over time. From the state at the time when the grounding work was done, the environment often changes due to improvement work in the surrounding area, etc., and it is difficult to check the grounding resistance value each time because it is not practically done. Met. In many cases, it has not been confirmed what the grounding resistance value is when several years to several decades have passed after grounding.

Japanese Unexamined Patent Publication No. 9-327119 Japanese Unexamined Patent Publication No. 9-147728

In this way, in order for the plug-in connection unit to generate an earth leakage current and operate the earth leakage breaker on the electric circuit, the grounding system that is the path of the earth 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 the plug-in connection unit is attached to the outlet, even if an earth leakage current is generated from the plug-in connection unit, There is a problem that the earth leakage breaker cannot be operated because the earth leakage current does not flow to the extent that the earth leakage breaker is operated.

That is, even though the plug-in connection unit itself is supplied with power and operates normally, the generated non-balanced current, which is a pseudo leakage current, does not flow to the ground circuit on the electric circuit, and the leakage breaker. There was a problem that a situation could occur in which the operation of was not performed.

The present invention has been made in view of this point, and an object of the present invention is whether or not the grounding system is functioning normally at the outlet to which the plug-in connection unit is connected, and over time. The purpose is to provide a plug-in connection unit having a function of confirming whether or not the ground resistance is functioning normally.

In order to solve the above problems, in the present invention, a plug-in connection unit used by connecting to an outlet circuit provided with a voltage pole (L pole), a neutral pole (N pole), and a ground pole (E pole). There is a plug blade that is inserted corresponding to the plug receiver at each pole provided in the outlet, a power supply circuit that is electrically connected to the plug blade to acquire drive power, and a power supply circuit that is connected to the power supply circuit. Between the power storage unit, a current generating unit having a constant current circuit capable of varying the output current between the neutral pole and the ground electrode in the outlet circuit, and passing a constant current, and the neutral pole and the ground electrode. Power is supplied from the voltage measuring unit that measures the voltage of the above, the ground resistance calculation unit that calculates the ground resistance from the current generated from the current generating unit and the voltage measured by the voltage measuring unit, and the power supply circuit. It is equipped with a seismic sensor unit that detects shaking due to an earthquake and outputs an output signal, and is connected to the outlet circuit by varying the magnitude of the current output from the current generation unit when calculating the ground resistance. When a constant current smaller than the operating sensitivity current of the leakage breaker is generated and the leakage breaker is operated, the leakage breaker is operated by generating a constant current larger than the operation sensitivity current from the current generation unit. At the same time, the current generating unit provides a plug-in connection unit characterized in that it receives an output signal from the seismic sensor unit and outputs a current to the outlet circuit .

According to the above configuration, since the earthing resistance calculation unit for calculating the earthing resistance from the current generated from the current generation unit and the voltage measured by the voltage measuring unit is provided, the outlet for mounting the plug-in connection unit is provided. At the location, it is possible to easily check whether the grounding system of the circuit is normal, and since the magnitude of the current output from the current generator is variable, it depends on the state of the grounding system of the circuit. The leakage breaker can be operated reliably.

The second invention is characterized in that the ground resistance calculation unit is provided with a repeat confirmation unit for performing the calculation of the ground resistance at predetermined time intervals.

According to the above configuration, the calculation for finding the grounding resistance in the grounding system can be repeated at predetermined time intervals, and by finding the magnitude of the grounding resistance that changes over time, the grounding system is normal. You can check whether it works or not.

The third invention is characterized by having a seismic sensor unit which is supplied with power from the power supply circuit, detects shaking due to an earthquake, and outputs an output signal.

According to the above configuration, the seismic sensor is provided by having a seismic sensor unit that is supplied with power from the power supply circuit, detects shaking due to an earthquake, and outputs an output signal, thereby detecting shaking due to an earthquake. The current can be output to the outlet circuit by receiving the output signal from the unit.

As described above, according to the present invention, whether or not the grounding system is functioning normally at the outlet to which the plug-in connection unit is connected, and whether or not the grounding resistance is functioning normally over time. It is possible to provide a plug-in connection unit with a function to check.

It is a schematic diagram of the electric wire to which 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 diagram of the current output from the plug-in connection unit to the electric circuit. 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. It should be noted that the following description of the preferred embodiment is essentially merely an example and does not limit the present invention, its application 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 (class B grounded) by providing the first electric terminal 21 on the ground. A distribution board 1 was provided on the load side of the transformer, and was grounded (class D grounded) by a second electrical terminal 104 provided on the ground via a centralized grounding terminal provided on the distribution board 1. It is an electric circuit having a grounding system.

In addition, in this application, as stipulated in JEAC8001 of the Extension Regulations, Electrical Technology Regulations, Equipment Used, issued by the Japan Electric Association, the neutral wire refers to the electric wire connected to the neutral pole of the power supply of the multi-wire type electric wire, and is a low voltage. A neutral wire or a grounded wire that is grounded due to technical needs in an electric line is called a grounded wire. For example, in a single-phase three-wire electric circuit, there are two voltage poles as voltage poles, that is, L1 pole and L2 pole, and N pole as a neutral pole. Further, in the single-phase two-wire type electric circuit, there is a grounded side electric wire that is grounded to the voltage electrode. The grounding electrode is the E electrode.

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

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

Reference numeral 3 is a plug-in connection unit. In FIG. 2, the plug connection unit 3 has a plug blade 31 connected to a voltage pole (L1 pole, L2 pole), a plug blade 32 connected to a neutral pole (N pole), and a grounding pole (E pole). A feeling that power is supplied from the plug blade 33 to be connected, the power supply circuit 34 that is electrically connected to these plug blades to acquire the driving power supply, and the power supply circuit 34, and the shaking due to the earthquake is detected and the output signal is output. The seismic sensor unit 35, the signal processing unit 30 that receives the output signal from the seismic sensor unit 35 and performs signal processing, and the signal processing unit 30 that receives the output signal from the signal processing unit 30 and has a neutral pole in the outlet circuit 105. A current generating unit 36 that generates a current between the ground electrode, a voltage measuring unit 37 that measures the voltage between the neutral electrode and the ground electrode, and a current and voltage measuring unit generated from the current generating unit. It is configured to include a ground resistance calculation unit that calculates the ground resistance from the voltage measured by. 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 varying the output current, and 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. The threshold value is 30 mA, which corresponds to the sensitivity of the earth-leakage circuit breaker installed in the house. First, a current smaller than 30 mA (for example, 20 mA) is generated between the neutral electrode and the ground electrode in the outlet circuit 105, and the voltage measuring unit 37 measures the voltage between the neutral electrode and the ground electrode. 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 within the normal range, the ground resistance display unit 39 displays the normal display. When the calculated ground resistance value is in the abnormal range (for example, several KΩ to MΩ), the ground resistance display unit 39 displays the abnormality.

In this case, when calculating the grounding resistance, the earth-leakage circuit can be calculated without operating the earth-leakage circuit breaker, and it can be confirmed whether or not the grounding system of the circuit is normal. Can be operated to prevent the circuit from being cut off.

As another embodiment, the magnitude of the current generated from the current generating unit 36 is set to a current larger than 30 mA (for example, 50 mA) corresponding to the sensitivity of the earth-leakage circuit breaker installed in a normal house. In this case, since a current larger than the operating sensitivity current of the earth-leakage circuit breaker is generated, the earth-leakage circuit breaker operates when calculating the ground resistance, but the actual cutoff operation determines whether the grounding system of the circuit is normal or not. You can check them together.

Further, the magnitude of the current output from the current generating unit 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 circuit breaker) to a large current (for example, 50 mA larger than the operating sensitivity current of the earth-leakage circuit breaker). Change and output. As a result, the grounding resistance value in the circuit can be obtained, the earth-leakage circuit breaker can be actually operated, and the state of the grounding system can be confirmed more reliably.

Further, in the signal processing unit 30, the ground resistance calculation unit that calculates the ground resistance at predetermined time intervals may be provided with a repeat confirmation unit that performs the calculation.

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

In addition to the repetitive confirmation unit, a storage unit (for example, internal memory or external memory of the microcomputer) that stores data such as the measured ground resistance value, voltage value, and grounding state confirmation result over time is provided. If data such as the grounding resistance value, voltage value, and grounding state confirmation result are accumulated over time and the accumulated data can be recalled and confirmed, the secular change of the grounding state can be confirmed and obtained each time. Various data can be used for various purposes such as being able to display the various data on the ground resistance display unit 39.

In addition to checking at predetermined time intervals, confirmation may be performed at a predetermined timing, for example, when the user wants to confirm that the season has changed. Further, a sensor for measuring changes in weather, temperature, and humidity may be provided so as to confirm when a predetermined change occurs.

38 is a power storage unit connected to the power supply circuit 34 and the signal processing unit 30. It is provided so that the signal processing unit can store the occurrence of the earthquake for a certain period of time when the power supply from the electric power company or the like is stopped after the occurrence of the earthquake. The power storage unit 38 is configured by using a capacitor, but may also be configured by using a primary battery or a secondary battery.

Reference numeral 40 is 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, an output signal is sent from the signal processing unit 30 to the current generation unit 36, and a current is generated in the outlet circuit 105.

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

The magnitude of the current generated from the current generating unit 36 is set to 30 mA as a threshold, but in addition to this, for example, 15 mA, which is a general leakage sensitivity current in a branch switch, is set as a second threshold, and the branch switch is used. A plug-in connection unit may be provided that cuts off the power supply to the branch circuit by the operation of the earth-leakage circuit breaker.

1 Distribution board 101 Main circuit breaker 102 Branch breaker 103 Centralized ground terminal 104 Second electrical terminal 105 Outlet 2 Transformer 21 First electrical terminal 3 Plug-in connection unit 30 Signal processing unit 31 Voltage pole plug blade 32 Plug blade of the sex pole 33 Plug blade of the ground pole 34 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 (2)

A plug-in connection unit used by connecting to an outlet circuit equipped with a voltage pole (L pole), a neutral pole (N pole), and a ground pole (E pole).
The plug blade that is inserted corresponding to the plug receiver at each pole provided in the outlet,
A power supply circuit that is electrically connected to the plug blade to obtain a drive power supply,
The power storage unit connected to the power supply circuit and
A current generating unit having a constant current circuit capable of varying the output current between the neutral pole and the grounding pole in the outlet circuit and allowing a constant current to flow.
A voltage measuring unit that measures the voltage between the neutral electrode and the ground electrode,
A 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.
It is equipped with a seismic sensor unit that is supplied with power from the power supply circuit, detects shaking due to an earthquake, and outputs an output signal .
When calculating the ground resistance, a constant current smaller than the operating sensitivity current of the earth-leakage circuit breaker connected to the outlet circuit is generated from the current generation unit, and when the earth-leakage circuit breaker is operated, the current generation unit operates the operation. By generating a constant current larger than the sensitivity current, the earth-leakage circuit breaker is operated and at the same time.
The current generation unit is a plug-in connection unit characterized in that it receives an output signal from the seismic sensor unit and outputs a current to the outlet circuit .
At predetermined time intervals, the ground resistance calculation unit that calculates the ground resistance is provided with a repeat confirmation unit that allows the calculation to be performed.
The plug-in connection unit according to claim 1, wherein the magnitude of the current output from the current generating unit is variable and output.

Images