JP5505876B2 - Grounding system connection status confirmation device - Google Patents

Description

According to the present invention, an electrical terminal provided on the ground is electrically connected to a protective ground conductor for grounding a device or the like via a ground wire electrically connected to the electrical terminal. The present invention relates to a device for confirming the state of grounding.

Conventionally, the protection of wiring when overcurrent or short-circuit current flows in the circuit, the electrical fire in the case where a ground fault occurs due to the deterioration of the insulation of the circuit or the load device, and the insulation of the load device As a result of the deterioration of the battery, a potential is generated between the earth and the casing that constitutes the load device, and various electrical accidents such as electric shocks that may occur when the human body touches the load device cause human life and property damage. In order to ensure safety, various power distribution devices have been developed, including wiring breakers and earth leakage breakers.

In particular, in order to prevent electrical accidents caused by the electric shock of the human body, the installation of earth leakage circuit breakers was obligated by the Industrial Safety and Health Regulations in 1969, and the number of deaths due to electric shocks has been decreasing year by year.

Well, it is well known that even before the installation of earth leakage circuit breakers became mandatory, protective grounding of equipment was carried out from the viewpoint of preventing electric shock accidents, and results were achieved in preventing electric shock accidents in the human body. It is.

For example, as shown in FIG. 9, even when the insulation of a load device installed in an electric circuit deteriorates and a ground voltage _Vg is generated between the ground and the housing of the load device, the ground resistance has no influence on the human body. Is as follows.

The R _B B type grounding resistance, represented the _{R D} D type grounding resistance, the _{V E} as path _{voltage, V g = {R D /} (R B + R D)} V E ··· ( Equation 1) and . Here, assuming that the resistance of the human body is 1 kΩ and the human body passage allowable current is 30 mA, which is limited to several minutes (electric shock current by Mr. Bigetzmeier and the physiological reaction of the human body), V _g = 30 V is assumed as the ground voltage. It is considered the upper limit of tolerance.

When path voltage _{V E} is 200V, by calculating by substituting _{V g} in Formula _{1, R B = 5.7R D ···} ( Equation 2), and the B type grounding resistance magnitude 10Ω In this case, since R _D ≈1.7Ω, the D-type ground resistance may be set to about 1.7Ω or less.

However, this ground resistance of 1.7Ω or less is actually a low ground resistance value that is difficult to obtain by normal installation work. When the ground is grounded, the soil is subjected to scientific treatment. For example, even if the ground resistance is obtained by using a ground resistance reducing agent using an inorganic high water content crystal, the ground resistance is maintained over time. In addition, it is difficult to check the grounding resistance over time because the surrounding environment often changes from the time when the grounding work was done, and it is difficult in practice. Was that.

In this way, electrical accidents due to electric shock from human bodies have been conventionally prevented by protective grounding of equipment, but in addition to grounding, by installing the above earth leakage breaker in the electrical circuit, If the insulation of the battery deteriorates and a leakage current of a predetermined magnitude is generated in the electric circuit, the leakage circuit breaker interrupts the electric circuit, thereby eliminating the risk of electric shock, and can be more effectively prevented. Is. However, even if the earth leakage breaker is installed in the electric circuit, if the grounding work is not sufficient, the time between the contact of the human body with the load equipment with deteriorated insulation and the breaking operation of the earth leakage breaker In this case, a leakage current flows through the human body, and the possibility of an electric shock accident cannot be completely denied.

Thus, grounding is very important to ensure the safety of human lives and property from various electrical accidents regardless of the presence or absence of the earth leakage breaker.

By the way, when the grounding work is performed, the grounding resistance, that is, the resistance between the ground and the grounding electrode which is an electrical terminal provided on the ground, depends on the kind of grounding work. It is necessary to check whether or not a predetermined resistance value is satisfied.

Grounding works are as described in the technical standards for electrical equipment. According to Article 19 of the interpretation of technical standards,
“Grounding work shall be conducted in accordance with Article 13 (Electrical circuit insulation) No. 6 and No. 7 (a), Article 23 (Grounding of the service area entrance), Article 28 (Electrical equipment grounding) ] Paragraphs 1, 2 and 4 and Article 42 (Grounding of lightning arresters) Grounding under the provisions of No. 2 (a), (3) (a) and (b), and the same high voltage overhead wire as the special high voltage overhead wire Except for the case where grounding work is performed on the parts to be installed on the support, the following four types are listed in the left column, and the grounding resistance value in each grounding work depends on the type of grounding work listed in the left column of the table. According to the type of each grounding work, the grounding resistance value is 10Ω in the case of Class A grounding work, and in the case of Class B grounding work. Is the amperage of the 1-wire ground fault current of the high-voltage side or extra high-voltage side of the transformer (150 If the ground voltage of the low piezoelectric circuit exceeds 150V due to the contact between the extra high voltage circuit and the low voltage circuit, the operating voltage is less than 35,000V, and the high voltage circuit is automatically used within 2 seconds. 300 when installing a device that cuts off a special high voltage circuit with a voltage of 35,000 V or less, or 600) when installing a device that automatically cuts off a high voltage circuit within a second or a voltage of 35,000 V or less. In the case of class C grounding work, the number of ohms equal to the divided value is 10Ω (when installing a device that automatically shuts off the electric circuit within 0.5 seconds when grounding occurs on the electric circuit in a low piezoelectric circuit. , 500Ω), and 100Ω for Class D grounding work (500Ω when installing a device that automatically shuts off the electric circuit within 0.5 seconds when the electric circuit is grounded in a low-piezoelectric circuit) , Ground resistance value is defined.

As a method for measuring the ground resistance value, the following method has been proposed conventionally.

First, in addition to the ground electrode for measuring the desired ground resistance, two auxiliary electrodes are used, and each electrode is placed in the soil at intervals of several meters so that it becomes the apex of the triangle. This is a so-called Kolash Bridge method in which the target ground resistance is measured by measuring the resistance between vertices.

Second, in addition to the ground electrode that measures the target ground resistance, two auxiliary electrodes are used and each electrode is placed in a straight line in the soil, and the target ground resistance is measured at one end. A ground electrode is disposed, one auxiliary electrode is installed at the other end separated by several tens of meters, and the other auxiliary electrode is disposed between the ground electrode and the other auxiliary electrode. This is a so-called electrode voltage drop method in which a target ground resistance is measured by passing a current between the auxiliary electrode and the ground electrode and measuring a voltage generated between the other auxiliary electrode and the ground electrode.

Thirdly, without using the auxiliary electrode, several tens of meters of electric wire is put on the ground, and the capacitor component formed between the electric wire and the ground and the inductance component existing in the electric wire are used to achieve the target. By applying a high-frequency signal via a known resistor between the ground electrode for measuring the ground resistance and the electric wire and resonating, the capacitor component and the inductance component are canceled out, and the high-frequency voltage at the time of resonance and the terminal This is a method using so-called resonance in which the ground resistance is measured by measuring the voltage.

However, in these measurement methods, it is necessary to drive each auxiliary electrode used in the measurement into the soil, and to arrange each electrode on a triangle or a straight line with a certain distance, and therefore, between the electrodes. The distance and the length of the wire used for measurement are several tens of meters. Actually, it is necessary for the measurement because the surrounding area is paved with concrete or asphalt, and the neighbors and fences are installed. In many cases, it is difficult to ensure a width of several tens of meters, and it is difficult to measure the ground resistance.

In addition, it is necessary to drive each auxiliary electrode used for measurement into the soil, and to place each electrode on a triangle or straight line with a distance of several tens of meters. Was very laborious and labor intensive.

Based on the importance of grounding and the effort of measuring grounding resistance, the technology for adjusting the grounding resistance value to be within the specified range and the measurement in places where grounding resistance measurement is difficult have been improved. Patent Documents 1 to 3 disclose techniques for improving work efficiency as follows.
JP 2006-275623 A JP 2007-163139 A JP 2007-127558 A

However, after the grounding work has been performed, an apparatus for confirming the grounding resistance over time has not been disclosed, and the work for measuring the grounding resistance requires labor as described above. In addition, even if the grounding work itself is done properly, the grounding system functions only when the protective grounding conductor and the grounding electrode are properly connected. It is important to check whether it is in a functioning state.

Moreover, the grounding resistance is expected to change depending on the environmental conditions surrounding the grounding system over time, taking into account the deterioration of functionality due to aging of various connection parts in the grounding system. It is desirable that a simple device can be used to confirm whether or not the grounding system is functioning.

In view of such a problem, the present invention can perform grounding resistance measurement work without any effort after grounding work is performed, and can confirm grounding resistance over time, that is, Grounding that can reduce the labor required for grounding resistance measurement as much as possible, and that it is very easy to check whether the grounding work itself is correct and the grounding system is functioning normally over time. An object is to provide a system connection state confirmation device.

In order to achieve the above object, claim 1 of the present invention provides:
The neutral side of the secondary winding of the transformer interposed in the circuit is grounded with a first electrical terminal on the ground,
In the electric circuit on the load side of the transformer, the second electrical terminal provided on the ground is
A plurality of protective ground conductors for grounding a device or the like via a ground wire electrically connected to the second electrical terminal;
A ground wire electrically connected to the second electrical terminal and a centralized ground terminal to which the plurality of protective ground conductors are respectively connected;
In a grounding system configured by being electrically connected,

A switch unit provided in the centralized ground terminal for separating / connecting the plurality of protective ground conductors and the ground wire;
A switch control unit for controlling on / off of the switch unit;

In the electric circuit on the load side of the transformer, a connection part electrically connected to the electric circuit and the ground system;
A voltage application unit for applying a voltage between the electric circuit connected by the connection unit and the grounding system;
A current detection unit for detecting a current flowing between the electric circuit and the ground system by a voltage applied by the voltage application unit;
With

When the current is detected by the current detection unit in each of the switch unit in the on state and the off state, it is determined that the grounding system is connected;
A determination unit that determines that the ground system is not connected when the current is not detected;
A grounding system connection state confirmation device is provided, characterized in that.

According to such a ground system connection state confirmation device, when the grounding on the neutral line side of the transformer secondary winding interposed in the electric circuit and the grounding on the load side of the electric circuit are performed, By measuring the current flowing between the wire and the protective earth conductor, or between the voltage line and the protective earth conductor, it is possible to determine whether or not the earthing system is connected, and to measure the earth resistance. As a result, the grounding work itself can be confirmed correctly. Further, by separating / connecting the protective grounding conductor and the grounding wire by the switch unit, a grounded state and a non-grounded state are created, and a current value or a voltage value in each state is compared, thereby grounding. It is possible to determine whether or not the system is connected, and it is possible to check the connection state of the ground system even though it is a very simple method. Further, as a result, for the grounding system provided on the load side in the electric circuit, a series of judgments by the judgment unit are performed on the centralized grounding terminal in which the protective grounding conductors are collected, so that each of the plurality of protective grounding conductors is determined. Without making judgments one by one, it is possible to reduce the labor required for measuring ground resistance as much as possible, and to check whether the grounding system itself is electrically connected normally to the electrical terminals connected to the ground.

Further, the connecting portion is for electrically connecting with a neutral line side of the electric circuit and a grounding system in the electric circuit on the load side of the transformer,
A voltage measuring unit for measuring a voltage between the electric circuit connected by the connecting unit and the grounding system;
When the voltage is measured by the voltage measuring unit, if the measured voltage value is approximately zero volts with respect to the line voltage between the neutral line and the voltage line of the transformer secondary winding, connection of the grounding system is performed. Is determined to be done,
When the voltage is measured, if the measured voltage value is not substantially zero volts with respect to the line voltage between the neutral line and the voltage line of the transformer secondary winding, the grounding system is not connected. A judgment unit for judging;
A grounding system connection state confirmation device may be configured by providing

According to such a grounding system connection state confirmation device, when grounding on the neutral wire side of the transformer secondary winding interposed in the electric circuit and grounding on the load side of the electric circuit are performed, the grounding side By detecting the voltage between the electric wire and the protective grounding conductor, it can be determined whether or not the grounding system is connected, and the labor required for measuring the grounding resistance can be reduced as much as possible. It can be confirmed that the construction itself is done correctly.

In addition, the connection portion is electrically connected to a voltage line side of the electric circuit and a grounding system in the electric circuit on the load side of the transformer,
A voltage measuring unit for measuring a voltage between the electric circuit connected by the connecting unit and the grounding system;
When the voltage is measured by the voltage measuring unit, when the voltage between the neutral line and the voltage line of the transformer secondary winding is approximately equal to the measured voltage value, the connection of the grounding system is performed. It is determined that
If the measured voltage value is not substantially equal to the line voltage between the neutral line and the voltage line of the transformer secondary winding when the voltage is measured, the grounding system is not connected. A judgment unit for judging;
It is also possible to provide a grounding system connection state confirmation device.

According to such a ground system connection state confirmation device, when the grounding on the neutral line side of the transformer secondary winding interposed in the electric circuit and the grounding on the load side of the electric circuit are performed, the voltage line By detecting the voltage between the protective earth conductor and the protective earth conductor, it can be determined whether or not the earthing system is connected, and the work required for measuring the earth resistance can be reduced as much as possible. You can confirm that it is done correctly.

In addition, the connection portion is electrically connected to a voltage line and a neutral line of the electric circuit and a grounding system,
When the determination unit determines the connection state of the ground system, the voltage line and the ground system or the neutral line and the ground system can be selectively connected among the electric circuit and the ground system connected by the connection unit. A connection state switching unit is provided, and when the connection unit connects the neutral line and the grounding system, the determination unit according to claim 2 performs the determination, while the connection unit connects the voltage line and the grounding system. In some cases, a grounding system connection state confirmation device may be provided, characterized in that a judgment unit that performs judgment by the judgment unit according to claim 3 is provided.

According to such a grounding system connection state confirmation device, measurement data of various voltage values or current values necessary for making a determination by the determination unit is transmitted to the voltage line and the grounding system or It can be obtained simply by selectively switching the connection between the neutral wire and the grounding system.

Delete

Delete

A display data generation unit that generates display data based on a determination result by the determination unit;
A grounding system connection state confirmation device may be provided by providing a display unit for displaying the display data generated by the display data generation unit.

According to such a grounding system connection state confirmation device, the judgment result by the judgment unit can be appropriately confirmed on the display unit, and the grounding system connection state can be conveniently confirmed even though it is a very simple method. can do.

In the grounding system,
A grounding system connection state confirmation device may be provided, characterized in that an iterative confirmation unit that performs the determination by the determination unit described above at predetermined time intervals is provided.

According to such a grounding system connection state confirmation device, it is possible to confirm whether or not the grounding system is functioning over time by performing the determination by the determination unit at predetermined time intervals.

Delete

Delete

According to the present invention, after the grounding work is performed, the grounding resistance can be measured without much effort, and the grounding resistance can be confirmed over time. A grounding system connection that can reduce the labor required for the measurement work as much as possible, and that the grounding work itself is done correctly and that it is very easy to check whether the grounding system is functioning normally over time. A state confirmation device can be provided.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each of the embodiments, the neutral wire side of the secondary winding of the transformer interposed in the electric circuit is grounded by providing the first electric terminal on the ground, and the first side provided on the ground on the load side of the electric circuit. A grounding system configured such that two electrical terminals are electrically connected to a protective grounding conductor for grounding a device or the like via a grounding wire electrically connected to the electrical terminal; The grounding system connection state confirmation apparatus which confirms the connection state of this is provided. In addition to general electric equipment, equipment includes general equipment that needs to be grounded, such as building equipment, copper strips provided in buildings, electric wires, and cubicle housings. Also, in this application, as defined in JEAC8001, an extension regulation electrical equipment usage facility edition published by the Japan Electric Association, a neutral wire is a wire connected to the neutral pole of a power source of a multi-wire circuit. A neutral wire or a grounded wire that is grounded according to technical requirements in the low piezoelectric path is called a grounded electric wire. For example, in a single-phase three-wire circuit, there are L1 and L2 poles as voltage poles and N poles as neutral poles. In the single-phase two-wire circuit, there is a ground-side electric wire that is grounded with the voltage electrode.

(First embodiment)
FIG. 1 shows a first embodiment of the present invention.

In the first embodiment, an electrical terminal 203 provided on the ground 1 is grounded via an earthing connection 202 electrically connected to the electrical terminal 203. A protective earth conductor (protective earthing conductor) 201 and a grounding state formed by being electrically connected to the neutral wire 102 side of the secondary winding of the transformer 100 interposed in the electric circuit; A grounding system connection state confirmation device 300 for judging and confirming by applying a voltage to the protective grounding conductor 201 is shown.

The neutral wire 102 side of the transformer 100 interposed in the electric circuit is grounded by the first electric terminal 103 and constitutes a load-side electric circuit together with the voltage line 101.

Here, the neutral wire 102 side of the secondary winding of the transformer 100 is grounded by the first electrical terminal 103 is Class B grounding as indicated in the technical standards for electrical equipment, On the side, the ground where the protective ground conductor 201 is made by the second electrical terminal 203 via the ground wire 202 is a D-type ground.

At this time, when the B-type grounding and the D-type grounding are performed, the protective ground conductor 201 includes the grounding wire 202, the second electrical terminal 203, the ground 1, and the first electrical terminal. It is in a state of being connected to the neutral wire 102 via 103. That is, if the B class ground resistance is R _B and the D class ground resistance is R _D , the combined resistance between the protective ground conductor 201 and the neutral wire 102 is
R _Total = R _B + R _D (Expression 3)

In this case, the power supply device 301 is connected to the neutral wire 102 and the protective ground conductor 201 on the load side of the electric circuit, and a voltage (voltage is set to E) is applied. The power supply device 301 may use an AC power supply or a DC power supply. An insulated power source in which the primary side and the secondary side are insulated may be used as the power source. Moreover, you may comprise using a capacitor | condenser as a DC power supply, for example.

Next, the current (meaning I) flowing between the neutral wire 102 and the protective ground conductor 201 is measured by the current measuring means 302. The current measuring means 302 may be configured using a current transformer (CT) or a Hall element, or may be configured using other general current sensors. Here, when the B type grounding and the D type grounding are performed, the combined resistance between the protective ground conductor 201 and the neutral wire 102 is R _Total = R as shown in (Equation 3). _Since it is expressed as _B + _RD , when voltage E is applied,
E / (R _B + R _D ) (Formula 4)
Is detected by the current measuring means 302.

At this time, when the current I is detected, it is a case where the B type grounding and the D type grounding are performed, so that the determination unit 303a determines that the grounding system is connected. .
If the current I is not detected, the protective ground conductor 201 is connected to the neutral wire 102 via the ground wire 202, the second electrical terminal 203, the ground 1, and the first electrical terminal 103. Since it is not connected, it is determined that the grounding system is not connected.
The determination unit 303a may be configured by using a microcomputer or IC, and may perform the determination by setting a threshold value for the detection current represented by the relationship of (Equation 4), or may be a resistor / diode. The determination may be made by configuring an electronic circuit using an operational amplifier or the like and detecting the magnitude of the detection current.

In this way, the connection state of the grounding system is determined by applying a voltage between the ground-side wire and the protective ground conductor in the electric circuit and detecting the current flowing between the ground-side wire and the protective ground conductor. Since it can be confirmed, it is possible to reduce the labor required for grounding resistance measurement as much as possible, and to easily confirm that the grounding work itself has been performed correctly.

The determination may be made by applying a voltage between the voltage line 101 side of the secondary winding of the transformer 100 interposed in the electric circuit and the protective ground conductor 201.

At this time, when the B-type grounding and the D-type grounding are performed, the protective ground conductor 201 includes the grounding wire 202, the second electrical terminal 203, the ground 1, and the first electrical terminal. 103, the neutral wire 102, and the voltage wire 101 side are connected through the secondary winding of the transformer. That is, if the class B ground resistance is R _B , the class D ground resistance is R _D , and the impedance of the secondary winding of the transformer is Z _L (= jωL: L is the inductance of the coil), The combined impedance with the sex line 102 is
Z _Total = R _B + R _D + Z _L (Expression 5)

In this case, the power supply device 301 is connected to the voltage line 101 and the protective ground conductor 201 on the load side of the electric circuit, and a voltage (voltage is set to E) is applied.

Next, a current flowing between the voltage line 101 and the protective ground conductor 201 (current is I) is measured by current measuring means. Here, when the B type grounding and the D type grounding are performed, the combined resistance between the protective grounding conductor 201 and the voltage line 101 is Z _Total = R _{B as shown in} (Equation 5). Since + R _D + Z _L , when voltage E is applied,
_{E / (R B + R D} + Z L) ··· ( Formula 6)
A current I expressed by the magnitude of is detected.

At this time, when the current I is detected, it is a case where the B type grounding and the D type grounding are performed, so that the determination unit 303a determines that the grounding system is connected. . When the current I is not detected, the protective ground conductor 201 is connected to the ground wire 202, the second electrical terminal 203, the ground 1, the first electrical terminal 103, the neutral wire 102, the transformer. Therefore, it is determined that the grounding system is not connected because it is not connected to the voltage line 101 side through the secondary winding.

In this way, the connection state of the ground system is confirmed by applying a voltage between the voltage line in the electric circuit and the protective ground conductor, and detecting the current flowing between the voltage line and the protective ground conductor. Therefore, it is possible to reduce the labor required for measuring the grounding resistance as much as possible and to easily confirm that the grounding work itself is correctly performed.

(Second embodiment)
FIG. 2 shows a second embodiment of the present invention.

In the second embodiment, an electrical terminal 203 provided on the ground 1 is connected to a protective ground conductor 201 for grounding a device or the like via a ground line 202 electrically connected to the electrical terminal 203; Measuring the voltage between the protective ground conductor 201 and the neutral wire 102 side of the secondary winding of the transformer 100 interposed in the electric circuit to determine the grounding state achieved by the electrical connection. This shows a grounding system connection state confirmation device 300 that judges and confirms the above.

The neutral wire 102 side of the transformer 100 interposed in the electric circuit is grounded by the first electric terminal 103 and constitutes a load-side electric circuit together with the voltage line 101.

Here, the neutral wire 102 side of the secondary winding of the transformer 100 is grounded by the first electrical terminal 103 is Class B grounding as indicated in the technical standards for electrical equipment, On the side, the ground where the protective ground conductor 201 is made by the second electrical terminal 203 via the ground wire 202 is a D-type ground.

At this time, when the B-type grounding and the D-type grounding are performed, the protective ground conductor 201 includes the grounding wire 202, the second electrical terminal 203, the ground 1, and the first electrical terminal. It is in a state of being connected to the neutral wire 102 via 103. That is, if the B class ground resistance is R _B and the D class ground resistance is R _D , the combined resistance between the protective ground conductor 201 and the neutral wire 102 is
R _Total = R _B + R _D (Expression 3)

In this case, the voltage measuring means 304 measures the voltage between the neutral wire 102 and the protective ground conductor 201 on the load side of the electric circuit. The voltage measuring means 304 may be configured by an electronic circuit, or may be configured by using a microcomputer, IC, or other voltage sensor having a voltage measuring function.

Here, when the B type grounding and the D type grounding are performed, the combined resistance between the protective ground conductor 201 and the neutral wire 102 is R _Total = R as shown in (Equation 3). _Since it is expressed as _B + R _D , the voltage between the neutral wire 102 and the protective ground conductor 201 simply corresponds to the open-circuit voltage of the resistance circuit in which the composite resistor is interposed, and the neutral wire and the voltage A measured voltage value of approximately zero volts is detected with respect to the line-to-line voltage.

Further, when the B type grounding and the D type grounding are not performed, an open section exists in the middle of the resistance circuit in which the combined resistance is interposed, and the voltage is not stable. In other words, the measured voltage value is not approximately zero volts with respect to the line voltage between the neutral line and the voltage line.

When a measured voltage value of approximately zero volts is detected with respect to the line voltage between the neutral line and the voltage line, it is the case where the B type grounding and the D type grounding are performed. It is determined in 303b that the grounding system is connected. In addition, when the measured voltage value is not approximately zero volts with respect to the line voltage between the neutral line and the voltage line, the protective ground conductor 201 is connected to the ground line 202 and the second electrical line. Since it is in a state where it is not connected to the neutral wire 102 via the target terminal 203, the ground 1, and the first electrical terminal 103, it is determined that the grounding system is not connected.
The determination unit 303b may be configured using a microcomputer or IC, and may perform the determination by setting a threshold value for the detection voltage, or may be configured as an electronic circuit using a resistor, a diode, an operational amplifier, or the like. However, the determination may be made by detecting the magnitude of the detection.

As described above, since the connection state of the grounding system can be confirmed by measuring the voltage between the ground-side electric wire in the electric circuit and the protective grounding conductor, labor for measuring the grounding resistance can be reduced as much as possible. At the same time, it is possible to easily confirm that the grounding work itself has been performed correctly.

(Third embodiment)
FIG. 3 shows a third embodiment of the present invention.

In the third embodiment, an electrical terminal 203 provided on the ground 1 is connected to a protective ground conductor 201 for grounding a device or the like via a ground line 202 electrically connected to the electrical terminal 203; By measuring the voltage between the protective ground conductor 201 and the voltage line 101 side of the secondary winding of the transformer 100 interposed in the electric circuit, the grounding state achieved by being electrically connected is determined. It shows a grounding system connection state confirmation device for judging and confirming.

The voltage line 101 side of the transformer 100 interposed in the electric circuit constitutes a load side electric circuit together with the neutral line 102 grounded by the first electric terminal 103.

Here, the neutral wire 102 side of the secondary winding of the transformer 100 is grounded by the first electrical terminal 103 is Class B grounding as indicated in the technical standards for electrical equipment, On the side, the ground where the protective ground conductor 201 is made by the second electrical terminal 203 via the ground wire 202 is a D-type ground.

At this time, when the B-type grounding and the D-type grounding are performed, the protective ground conductor 201 includes the grounding wire 202, the second electrical terminal 203, the ground 1, and the first electrical terminal. 103, the neutral wire 102, and the voltage wire 101 side are connected through the secondary winding of the transformer. That is, if the class B ground resistance is R _B , the class D ground resistance is R _D , and the impedance of the secondary winding of the transformer is Z _L (= jωL: L is the inductance of the coil), The combined impedance with the sex line 102 is
Z _Total = R _B + R _D + Z _L (Expression 5)

In this case, the voltage between the voltage line 101 and the protective ground conductor 201 on the load side of the electric circuit is measured. The voltage measuring means 304 may be configured by an electronic circuit, or may be configured by using a microcomputer, IC, or other voltage sensor having a voltage measuring function.

Here, when the B type grounding and the D type grounding are performed, the combined impedance between the protective ground conductor 201 and the voltage line 101 is Z _Total = R _{B as shown in} (Equation 5). + R _D + Z _L , the voltage between the voltage line 101 and the protective ground conductor 201 simply corresponds to the voltage at the open end of the resistor-coil series circuit in which the combined impedance is interposed. A measured voltage value approximately equal to the line voltage between the sex line and the voltage line is detected.

When the B type grounding and the D type grounding are not performed, an open section exists in the middle of the resistance circuit in which the combined impedance is present, and the voltage is not stable. That is, a measured voltage value that is not substantially equal to the line voltage between the neutral line and the voltage line is measured.

When a measurement voltage value that is substantially equal to the line voltage between the neutral line and the voltage line is detected, the B-type grounding and the D-type grounding are performed, so the determination unit 303c Thus, it is determined that the grounding system is connected. When the measured voltage value is not substantially equal to the line voltage between the neutral line and the voltage line, the protective ground conductor 201 is connected to the ground line 202 and the second electrical line. Since the terminal 203, the ground 1, the first electrical terminal 103, the neutral wire 102, and the secondary winding of the transformer are not connected to the voltage line 101 side, the ground system is connected. Judge that it is not.

The determination unit 303c may be configured using a microcomputer or IC, and may perform the determination by setting a threshold value for the detection voltage, or may be configured as an electronic circuit using a resistor, a diode, an operational amplifier, or the like. However, the determination may be made by detecting the magnitude of the detection.

As described above, since the connection state of the grounding system can be confirmed by measuring the voltage between the voltage line in the electric circuit and the protective grounding conductor, the labor for measuring the grounding resistance can be reduced as much as possible. Therefore, it can be easily confirmed that the grounding work itself has been performed correctly.

(Fourth embodiment)
FIG. 4 shows an example of the fourth embodiment of the present invention.
In the fourth embodiment, an electrical terminal 203 provided on the ground 1 is connected to a protective ground conductor 201 for grounding a device or the like via a ground line 202 electrically connected to the electrical terminal 203; A connection part is provided for electrically connecting the grounding state made by being electrically connected to the voltage line and neutral line of the circuit and the grounding system,
When the determination unit determines the connection state of the ground system, the voltage line and the ground system or the neutral line and the ground system can be selectively connected among the electric circuit and the ground system connected by the connection unit. A connection state switching unit is provided, and the determination shown in any one of the first to third embodiments described above is selectively performed or the first to third embodiments described above are used. It shows a grounding system connection state confirmation device that is implemented by combining the judgments shown.

A connection state switching unit 305 may be configured using a relay so as to selectively switch the connection between the voltage line and the neutral line, or electronically selects a connection inside the microcomputer or IC. You may comprise with a semiconductor switch.

Then, the determination unit 304d performs the determination of the third embodiment described above when the voltage line is selected, and performs the determination of the second embodiment described above when the neutral line is selected. It is better to combine functions. Further, it may be configured such that the determination of the first embodiment described above is performed in the selected electric circuit.

Furthermore, the determination unit 304d may be configured to combine the determinations of the first embodiment to the third embodiment described above in a composite manner on the electrical path selected by the connection state switching unit 305.

(Fifth embodiment)
FIG. 5 shows an example of the fifth embodiment of the present invention.

In the fifth embodiment, an electrical terminal 203 provided on the ground 1 is connected to a protective ground conductor 201 for grounding a device or the like via a ground line 202 electrically connected to the electrical terminal 203; A switch means for separating / connecting the protective ground conductor and the ground wire is provided for the grounding state achieved by electrical connection, and the protective ground conductor and the ground wire are connected by the switch means. The ground state A and the non-ground state B are created by controlling the separation / connection, and in each of the ground state A and the non-ground state B, any one of the first embodiment to the fourth embodiment described above. 1 shows a ground system connection state confirmation device that performs the judgment shown in FIG. 1 and confirms the measured current value or the measured voltage value obtained in both the grounded state A and the ungrounded state B by comparison.

First, this embodiment will be described based on the case where the switch means 401 is interposed between the protective ground conductor 201 and the ground line 202 based on the first embodiment described above. The switch means 401 may use a relay circuit or an electronic switch configured using an IC or a microcomputer.

In this case, first, with the switch means 401 closed (grounding state A), the power supply device 301 is connected to the neutral wire 102 and the protective grounding conductor 201 on the load side of the electric circuit, and the voltage (the voltage is assumed to be E). Apply. Then, the current measuring means 302 measures the current flowing between the neutral wire 102 and the protective ground conductor 201 (the current is I). Here, when the B type grounding and the D type grounding are performed, the combined resistance between the protective ground conductor 201 and the neutral wire 102 is R _Total = R as shown in (Equation 3). _Since it is expressed as _B + _RD , when voltage E is applied,
E / (R _B + R _D ) (Formula 4)
A current I expressed by the magnitude of is detected.

Subsequently, in a state where the switch means 401 is opened (non-grounding state B), the power supply device 301 is connected to the neutral wire 102 and the protective grounding conductor 201 on the load side of the electric circuit, and the voltage (voltage is assumed to be E). Apply. Then, the current flowing between the neutral wire 102 and the protective ground conductor 201 (current is I) is measured by a current measuring means. At this time, since the protective ground conductor 201 and the neutral wire 102 are separated by the switch means 401, the current I is not detected.

Here, when the current values obtained by the determination unit 303e in a state where the switch unit 401 is closed (grounding state A) and an open state (non-grounding state B) are compared, When seed grounding is performed, the detected current value I changes between the ground state A and the non-ground state B, and when the class B grounding and the class D grounding are not performed. Is a state in which the protective ground conductor 201 is not connected to the neutral wire 102 via the ground wire 202, the second electrical terminal 203, the ground 1, and the first electrical terminal 103. The current value I does not change between the ground state A and the non-ground state B.

Therefore, the determination unit 303e determines that the grounding system is connected when there is a change in the current value as a result of the comparison of the current values. If the current value is not changed as a result of the comparison of the current values, it is determined that the ground system is not connected.

Next, based on the second embodiment described above, a description will be given of the case where the switch means 401 is interposed between the protective ground conductor 201 and the ground line 202.

In this case, first, the voltage between the neutral wire 102 and the protective ground conductor 201 on the load side of the electric circuit is measured with the switch means 401 closed (ground state A).

Here, when the B type grounding and the D type grounding are performed, the combined resistance between the protective ground conductor 201 and the neutral wire 102 is R _Total = R as shown in (Equation 3). _Since it is expressed as _B + R _D , the voltage between the neutral wire 102 and the protective ground conductor 201 simply corresponds to the open-circuit voltage of the resistance circuit in which the composite resistor is interposed, and the neutral wire and the voltage A measured voltage value of approximately zero volts is detected with respect to the line-to-line voltage.

Subsequently, the voltage between the neutral wire 102 and the protective ground conductor 201 on the load side of the electric circuit is measured with the switch means 401 opened (non-grounded state B).

In this case, since the protective ground conductor 201 and the voltage line 101 are separated by the switch means 401, the voltage is not stable. That is, the measured voltage value is not substantially equal to the line voltage between the neutral line and the voltage line.

Here, when the voltage values obtained when the switch means 401 is closed (grounding state A) and opened (non-grounding state B) are compared, the B type grounding and the D type grounding are performed. The detected voltage value E varies between the ground state A and the non-ground state B, and when the B-type ground and the D-type ground are not performed, the protective ground A conductor 201 is connected to the voltage line 101 side via the ground wire 202, the second electrical terminal 203, the ground 1, the first electrical terminal 103, the neutral wire 102, and the secondary winding of the transformer. Therefore, the voltage value E does not change between the ground state A and the non-ground state B.

Therefore, the determination unit 303e determines that the grounding system is connected when there is a change in the voltage value as a result of the comparison of the voltage values. If the voltage value is not changed as a result of the comparison of the voltage values, it is determined that the ground system is not connected.

Next, a description will be given of a case where the switch means 401 is interposed between the protective ground conductor 201 and the ground line 202 based on the above-described third embodiment.

In this case, first, the voltage between the voltage line 101 and the protective ground conductor 201 on the load side of the electric circuit is measured with the switch means 401 closed (grounding state A).

Here, when the B type grounding and the D type grounding are performed, the combined resistance between the protective ground conductor 201 and the neutral wire 102 is Z _Total = R as shown in (Equation 5). _Since it is expressed as _B + R _D + Z _L , the voltage between the neutral wire 102 and the protective grounding conductor 201 simply corresponds to the voltage at the open end of the resistor-coil series circuit in which the combined impedance is interposed, A measured voltage value approximately equal to the line voltage between the neutral line and the voltage line is detected.

Then, the voltage between the voltage line 101 and the protective ground conductor 201 on the load side of the electric circuit is measured with the switch means 401 opened (non-grounded state B).

In this case, since the protective ground conductor 201 and the voltage line 101 are separated by the switch means 401, the voltage is not stable. That is, the measured voltage value is not substantially equal to the line voltage between the neutral line and the voltage line.

Here, when the voltage values obtained when the switch means 401 is closed (grounding state A) and opened (non-grounding state B) are compared, the B type grounding and the D type grounding are performed. The detected voltage value E varies between the ground state A and the non-ground state B, and when the B-type ground and the D-type ground are not performed, the protective ground A conductor 201 is connected to the voltage line 101 side via the ground wire 202, the second electrical terminal 203, the ground 1, the first electrical terminal 103, the neutral wire 102, and the secondary winding of the transformer. Therefore, the voltage value E does not change between the ground state A and the non-ground state B.

Therefore, the determination unit 303e determines that the grounding system is connected when there is a change in the voltage value as a result of the comparison of the voltage values. If the voltage value is not changed as a result of the comparison of the voltage values, it is determined that the ground system is not connected.

Similarly, when based on the case of the fourth embodiment described above, the determination is made in combination or alternatively or in combination.

(Sixth embodiment)
FIG. 6 shows an example of the sixth embodiment of the present invention.

In the sixth embodiment, an electrical terminal 203 provided on the ground 1 is connected to a protective ground conductor 201 for grounding a device or the like via a ground line 202 electrically connected to the electrical terminal 203; Based on the determination result by the determination unit described above, the display data generation unit that generates display data and the display data generated by the display data generation unit A grounding system connection state confirmation device is provided that includes a display unit to display and performs the determination shown in any one of the first to fifth embodiments described above and confirms it.

Reference numeral 306 denotes a display data generation unit that generates display data to be displayed on the display unit 307 based on the determination result output from the determination unit. Specifically, it may be constituted by a microcomputer or a driver having a character generator function. The display data generates data that can grasp the status of the grounding system, such as the state of the grounding system connection, the measured current value, the measured voltage value, and the grounding resistance value obtained as a result of the judgment unit calculation. It is preferable to output to 307.

Also, in a simpler manner, the green LED is lit when it is determined that the ground connection is good, and the red LED is lit when it is determined that the ground connection is not good. It may be configured.

The display unit 307 is configured using a liquid crystal display. The liquid crystal display appropriately displays the character display data described above. The display unit 307 may be configured using an organic EL display having a display function visible from the outside, an LED, or the like.

(Seventh embodiment)
FIG. 7 shows an example of the seventh embodiment of the present invention.

In the seventh embodiment, an electrical terminal 203 provided on the ground 1 is connected to a protective ground conductor 201 for grounding a device or the like via a ground line 202 electrically connected to the electrical terminal 203; Repeated confirmation means 501 for confirming the grounding state made by electrical connection at a predetermined time interval is provided, and any one of the first to sixth embodiments described above is provided. 1 shows a grounding system connection state confirmation device that performs the determination in the illustrated embodiment and repeatedly confirms over time.

The iterative confirmation unit 501 may be configured using an electronic timer or a programmed microcomputer so that the series of determinations described above are performed periodically.

Since the repeater 501 can check the connection state of the grounding system at predetermined time intervals, the grounding resistance that changes over time and the functionality deterioration due to aging of various connection parts in the security system grounding system can be easily performed. I can confirm.

In addition to the repetitive confirmation means 501, storage means for accumulating data such as the measured current value, voltage value, ground state confirmation result, etc. in the above-described embodiment over time, such as a microcomputer internal memory or an external memory Provided that the data such as the current value, voltage value, ground state confirmation result, etc. can be called and confirmed over time, and various data obtained each time a series of judgments are made are displayed on the display unit. It can be used in various ways such as being able to be displayed.

In addition to confirmation at predetermined time intervals, confirmation may be performed when it is desired to confirm manually at a predetermined timing, for example, at the turn of the season. In addition, a sensor for measuring a change in weather, temperature, and humidity may be provided to check when there is a predetermined change.

(Eighth embodiment)
FIG. 8 shows an example of the eighth embodiment of the present invention.

In the eighth embodiment, an electrical terminal 203 provided on the ground 1 has a plurality of protective ground conductors 201 for grounding a device or the like via a ground line 202 electrically connected to the electrical terminal 203. When provided, a connection portion that is electrically connected to the centralized ground terminal that collects the protective ground conductor 201 is provided, and the above-described centralized ground terminal is used instead of the protective ground conductor. The grounding system connection state confirmation apparatus which performs and confirms the judgment of embodiment shown in any one of 1st Embodiment thru | or 7th Embodiment is shown.

The centralized grounding terminal 601 is provided for the purpose of sharing the grounding wire 202 electrically connected to the second electrical terminal 203 when a plurality of the protective grounding conductors 201 for grounding a device or the like are provided. This is for collectively connecting the protective ground conductors 201.

In place of the protective ground conductor 201 in the first to seventh embodiments described above, a plurality of protective ground conductors are provided by performing a series of determinations on the concentrated ground terminal 601. In this case, it is effective in that the grounding state for all the protective ground conductors 201 can be confirmed by a single determination without making a determination for each of the protective ground conductors 201 one by one.

It should be noted that the grounding system connection state confirmation device 300 shown in the present embodiment is provided on a distribution board or relay box into which a grounding wire or a protective grounding conductor that is a grounding system is provided, so that the grounding system connection state This can be easily confirmed.

It should be noted that the present invention is not limited to the above-described embodiment, and can be appropriately applied as necessary without departing from the gist of the invention.

For example, for the purpose of confirming in more detail whether or not the grounding system is in a normally functioning state, the state in which the type B grounding and the type D grounding are normally performed is defined as a basic state. The measurement current value and the measurement voltage value obtained when the measurement current value and the measurement voltage value shown in the above-described embodiment are stored in the storage unit as basic data and the above process is repeated over time. By comparing the basic data with the basic data in the judgment unit, it is determined whether there is a deviation from the normal state. If the magnitude of the deviation becomes a predetermined magnitude, You may comprise so that it may judge that a state is not functioning normally.

In addition, as the basic data stored in the storage unit, resistance value data in the grounding system is actually obtained, and the measurement current value and the measurement voltage value obtained as a result of repeating the determination over time are obtained. It may be configured to obtain resistance value data from the data, and to determine that the grounding state is not functioning normally when the difference between the respective resistance value data becomes a predetermined magnitude.

Further, resistance value data obtained from the ground data obtained from the basic data, and measured current value and measured voltage data obtained as a result of repeating the above-mentioned process over time, are described above. For example, it is judged by the judging section whether or not the ground resistance value is within 100Ω in the case of class D grounding work described in the technical standards for the electrical equipment. May be configured to determine that is not functioning properly.

In addition, the ground system connection state confirmation device 300 is provided with a communication unit, and the basic data described above, measurement current value and measurement voltage value data obtained by repeating the above-described process over time, and these data. Whether the installation status is functioning normally on the external device by making it possible to obtain the resistance value data obtained from the above and data such as whether the grounding status is normal on the external device. You may comprise so that it can confirm.

As the communication unit, a serial communication unit using RS-232C is provided, or a communication unit based on the Ethernet (registered trademark) system defined by IEEE 802.3 is provided so that it can be connected to a general residential LAN. It may be configured. In addition, a wireless communication unit such as a specific low power wireless or wireless LAN method, or a power line carrier communication unit that superimposes data on the power line may be provided.

The external device may be a mobile phone that can be connected to the general Internet, a computer, or a dedicated data processing device that stores the various data described above, performs arithmetic processing, and displays the data. Further, the data obtained by the grounding system connection state confirmation device 300 is accumulated in a data accumulation server provided on the Internet via the gateway device, via the Internet network, and the data storage server from the power company side. It may be configured to check whether or not the grounding state is functioning normally by accessing the data and referring to the data from the target grounding system connection state confirmation device 300.

As a result, in the past, when checking the grounding condition, it was necessary to check at the relevant site, but the power company side can check the grounding condition. Whether in or outside the jurisdiction, it is possible to statistically check the state of grounding over a wide range without any regional restrictions.

Furthermore, by obtaining changes in the data over time from the obtained grounding state data, it is possible to determine how the grounding state has changed over time, and to determine the determined grounding resistance value. If it exceeds, or if it is likely to exceed a predetermined grounding resistance value, for example, the grounding state at the location can be confirmed, and improvement can be made in advance so that the grounding state becomes normal.

In addition, the ground system connection state confirmation device 300 is provided with a notification unit, and the basic data described above, the measured current value and measured voltage value data obtained by repeating the determination over time, and these data. When the resistance value data obtained from the above and data such as whether the grounding state is normal exceed a predetermined value or greatly deviate from the notification unit, the grounding state is normal. It may be configured to notify that it is not, and to confirm the state of grounding in the surroundings.

Further, bidirectional communication is performed between the server on the power company side and the grounding system connection state confirmation device 300, and the grounding state grasped on the power company side is notified from the notification unit. , The state of grounding can be confirmed more appropriately.

For the voice data to be notified, a microcomputer may be provided in the grounding system connection state confirmation device 300, and an expected voice may be stored in the microcomputer in advance. Alternatively, the voice data may be transmitted to the communication unit of the grounding system connection state confirmation apparatus 300 via the Internet network, and the voice data may be notified from the notification unit.

The present invention can be applied to an apparatus for confirming a grounding state in a grounding system. This is mainly effective for confirming the grounding in the distribution board that houses various distribution devices. The distribution board can be applied to residential distribution boards as well as industrial distribution boards, so that the state of grounding can be controlled against grounding in various locations, whether residential or industrial. There is a possibility that a device that can be confirmed can be provided.

Explanatory drawing of the device which confirms the state of grounding according to the first embodiment Explanatory drawing of the device which confirms the state of grounding according to the second embodiment Explanatory drawing of the device which confirms the state of grounding according to the third embodiment Explanatory drawing of the device which confirms the state of grounding according to the fourth embodiment Explanatory drawing of the device which confirms the state of grounding according to the fifth embodiment Explanatory drawing of the device which confirms the state of grounding concerning a 6th embodiment Explanatory drawing of the device which confirms the state of grounding concerning a 7th embodiment Explanatory drawing of the apparatus which confirms the state of grounding concerning 8th embodiment Illustration of ground voltage and ground resistance when insulation of load equipment installed in electric circuit deteriorates

DESCRIPTION OF SYMBOLS 1 Ground 100 Transformer 101 Voltage line 102 Neutral line 103 1st electrical terminal 201 Protective ground conductor 202 Ground line 203 2nd electrical terminal 300 Grounding system connection state confirmation apparatus 301 Power supply apparatus 302 Current measurement means 303 Determination part 304 Voltage measurement unit 305 Connection state switching unit 306 Display data generation unit 307 Display unit 401 Switch unit 501 Repetition confirmation unit 601 Centralized ground terminal

Claims (6)

The neutral side of the secondary winding of the transformer interposed in the circuit is grounded with a first electrical terminal on the ground,
In the electric circuit on the load side of the transformer, the second electrical terminal provided on the ground is
A plurality of protective ground conductors for grounding a device or the like via a ground wire electrically connected to the second electrical terminal;
A ground wire electrically connected to the second electrical terminal and a centralized ground terminal to which the plurality of protective ground conductors are respectively connected;
In a grounding system configured by being electrically connected,

A switch unit provided in the centralized ground terminal for separating / connecting the plurality of protective ground conductors and the ground wire;
A switch control unit for controlling on / off of the switch unit;

In the electric circuit on the load side of the transformer, a connection part electrically connected to the electric circuit and the ground system;
A voltage application unit for applying a voltage between the electric circuit connected by the connection unit and the grounding system;
A current detection unit for detecting a current flowing between the electric circuit and the ground system by a voltage applied by the voltage application unit;
With

When the current is detected by the current detection unit in each of the switch unit in the on state and the off state, it is determined that the grounding system is connected;
A determination unit that determines that the ground system is not connected when the current is not detected;
A grounding system connection state confirmation device characterized by comprising:
The connecting portion is for electrically connecting with a neutral line side of the electric circuit and a grounding system in the electric circuit on the load side of the transformer,
A voltage measuring unit for measuring a voltage between the electric circuit connected by the connecting unit and the grounding system;
When the voltage is measured by the voltage measuring unit, if the measured voltage value is approximately zero volts with respect to the line voltage between the neutral line and the voltage line of the transformer secondary winding, connection of the grounding system is performed. Is determined to be done,
When the voltage is measured, if the measured voltage value is not substantially zero volts with respect to the line voltage between the neutral line and the voltage line of the transformer secondary winding, the grounding system is not connected. A judgment unit for judging;
The grounding system connection state confirmation apparatus according to claim 1, comprising:
The connection part is for electrically connecting the voltage line side of the electric circuit and the grounding system in the electric circuit on the load side of the transformer,
A voltage measuring unit for measuring a voltage between the electric circuit connected by the connecting unit and the grounding system;
When the voltage is measured by the voltage measuring unit, when the voltage between the neutral line and the voltage line of the transformer secondary winding is approximately equal to the measured voltage value, the connection of the grounding system is performed. It is determined that
If the measured voltage value is not substantially equal to the line voltage between the neutral line and the voltage line of the transformer secondary winding when the voltage is measured, the grounding system is not connected. A judgment unit for judging;
The grounding system connection state confirmation apparatus according to claim 1, comprising:
The connection portion is electrically connected to a voltage line and a neutral line of the electric circuit and a grounding system,
When the determination unit determines the connection state of the ground system, the voltage line and the ground system or the neutral line and the ground system can be selectively connected among the electric circuit and the ground system connected by the connection unit. A connection state switching unit is provided,
When the connection unit connects the neutral wire and the grounding system, the determination unit according to claim 2 performs the determination,
The grounding system connection according to claim 2 or 3, further comprising a determination unit that makes a determination by the determination unit according to claim 3 when the connection unit connects the voltage line and the grounding system. Status confirmation device.
A display data generation unit that generates display data based on a determination result by the determination unit;
The ground system connection state confirmation apparatus according to any one of claims 1 to 4, further comprising a display unit that displays the display data generated by the display data generation unit.
In the grounding system,
The grounding system connection state confirmation apparatus according to any one of claims 1 to 5, further comprising an iterative confirmation unit that performs the determination by the determination unit described above at a predetermined time interval.

Images