JP5419030B2 - Grounding system connection status confirmation method - 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 method 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, there is no disclosure of a technique for confirming the ground resistance over time after the grounding work is performed, and as described above, labor is required for measuring the ground resistance. 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 method can be used to check whether the grounding system is in a functioning state.

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, It is possible to check the grounding resistance measurement work as much as possible, and to check whether the grounding work itself has been done correctly and that the grounding system is functioning normally over time using a very simple method. It aims to provide a possible method.

In order to achieve the above object, claim 1 of the present invention provides:
The neutral line side of the secondary winding of the transformer interposed in the electric circuit is grounded by providing a first electrical terminal on the ground, and the second electric circuit provided on the ground in the electric circuit on the load side of the transformer. A plurality of protective ground conductors for grounding a device and the like, and a second electrical terminal electrically connected to the second electrical terminal via a ground wire electrically connected to the second electrical terminal; In a grounding system configured by being electrically connected to a concentrated grounding terminal to which each of the grounded wires and the plurality of protective grounding conductors is connected , the plurality of protective grounding conductors and the grounding wires are separated / Providing a switch means for connection, controlling the on / off of the switch means, and between the ground-side electric wire and the protective ground conductor in the load-side electric circuit in each of the on-state and off-state of the switch means. Applying voltage to A step of detecting a current flowing between said ground side electric wire and the protective earth conductor, and the current value obtained when the switch means is in ON state, obtained when the switching means of the switching state A step of comparing the current value, a step of determining that the grounding system is connected if there is a change in the current value as a result of the comparison, and no change in the current value as a result of the comparison. In some cases, the method includes a step of determining that the connection of the grounding system is not made, and a grounding system connection state confirmation method is provided.

According to such a grounding system connection state confirmation method, 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 current flowing between the electric wire and the protective grounding conductor, it can be determined whether or not the grounding system is connected, and the labor for measuring the grounding resistance can be reduced as much as possible. It can be confirmed that the grounding work itself is done correctly.

Further, the switch means separates / connects the protective ground conductor and the ground wire to create a ground state and a non-ground state, and compares the current value in each state to connect the ground system. It is possible to determine whether the grounding system is connected even though it is a very simple method.

In addition, for the grounding system provided on the load side in the electric circuit, a series of steps are performed for each of the plurality of protective grounding conductors by performing a series of steps on the centralized grounding terminal that combines the plurality of protective grounding conductors Therefore, it is possible to reduce the labor required for measuring the grounding resistance as much as possible and to check whether the grounding system itself is electrically connected to the electrical terminal connected to the ground.

Delete

Delete

Delete

Delete

Delete

Delete

Delete

Delete

In the grounding system,
A grounding system connection state confirmation method may be provided, including the step of performing the series of steps described above at predetermined time intervals.

According to such a grounding system connection state confirmation method, it is possible to confirm whether or not the grounding system is functioning over time by performing a series of steps 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 method that can reduce the labor involved in the measurement work as much as possible, and can confirm whether the grounding work itself has been performed correctly and whether the grounding system is functioning normally over time in a very simple manner. 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; It provides a method for confirming the connection state. 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; This is determined and confirmed by applying a voltage between the protective ground conductor 201 and the protective ground conductor 201.

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, a current flowing between the neutral wire 102 and the protective ground conductor 201 (current is I) is measured by a current measuring means. 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.

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 the determination unit 303 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.

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.

(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. Judgment is made based on 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 between the neutral wire 102 and the protective ground conductor 201 on the load side of the electric circuit is measured.

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. In 303, it is determined 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.

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 applying a voltage between the protective grounding 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 the electrical connection is established. Judgment and confirmation are made.

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 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. The power supply device 301 may use an AC power supply or a DC power supply.

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 the determination unit 303 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.

(Fourth embodiment)
FIG. 4 shows a 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; 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. Judgment and confirmation are made.

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.

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. 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.

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.

(Fifth embodiment)
FIG. 5 shows a 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, either the first embodiment or the third embodiment described above is used. The process shown in FIG. 1 is performed, and the measurement current values obtained in both the ground state A and the non-ground state B are compared to confirm.

This embodiment will be described in the case where the switch means 401 is interposed between the protective ground conductor 201 and the ground line 202 in the first embodiment described above.

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 flowing between the neutral wire 102 and the protective ground conductor 201 (current is I) is measured by a current measuring means. 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 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 ground current value I changes between the ground state A and the non-ground state B. If the B-type ground and the D-type ground are not provided, the protective ground Since the 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 is The ground state A and the non-ground state B do not change.

Therefore, if the current value is changed as a result of the comparison of the current values, it is determined that the grounding system is connected. 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, 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 in the third embodiment described above.

In this case, first, in a state where the switch means 401 is closed (ground state A), the power supply device 301 is connected to the voltage line 101 and the protective ground conductor 201 on the load side of the circuit, and the voltage (voltage is assumed to be E). Apply. Then, a current (current is I) flowing between the voltage line 101 and the protective ground conductor 201 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.

Subsequently, with the switch means 401 opened (non-grounded state B), the power supply device 301 is connected to the voltage line 101 and the protective grounding conductor 201 on the load side of the electric circuit, and a voltage (voltage is assumed to be E) is applied. To do. Then, a current (current is I) flowing between the voltage line 101 and the protective ground conductor 201 is measured by current measuring means. At this time, since the protective ground conductor 201 and the voltage line 101 are separated by the switch means 401, the current I is not detected.

Here, when the current 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 ground current value I changes between the ground state A and the non-ground state B. If the B-type ground and the D-type ground are not provided, the protective ground Since the 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 is The ground state A and the non-ground state B do not change.

Therefore, if the current value is changed as a result of the comparison of the current values, it is determined that the grounding system is connected. 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.

(Sixth embodiment)
FIG. 6 shows a 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; 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, either the second embodiment or the fourth embodiment described above is used. The process shown in FIG. 1 is performed, and the measurement voltage values obtained in both the ground state A and the non-ground state B are compared to confirm.

This embodiment will be described in the case where the switch means 401 is interposed between the protective ground conductor 201 and the ground line 202 in the above-described second embodiment.

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 hits the voltage at the open end of the resistance circuit in which the combined resistor is interposed, and the neutral wire and A measured voltage value of approximately zero volts is detected with respect to the line voltage with the voltage line.

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 neutral wire 102 are separated by the switch means 401, 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.

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 Since the 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 voltage value E is The ground state A and the non-ground state B do not change.

Therefore, if there is a change in the voltage value as a result of the comparison of the voltage values, it is determined that the ground system is connected. 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.

Subsequently, 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 the above-described fourth 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.

Subsequently, 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, if there is a change in the voltage value as a result of the comparison of the voltage values, it is determined that the ground system is connected. 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.

(Seventh embodiment)
FIG. 7 shows a 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. The process of the embodiment shown is performed and confirmed over time.

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

Since the repeater 501 can confirm the connection state of the grounding system at predetermined time intervals, it is possible to easily confirm the ground resistance that changes over time, and the functionality deterioration due to aging of various connection parts in the grounding system. .

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 If it is configured so that data such as the current value, voltage value, and ground state confirmation result can be confirmed over time, various data obtained each time a series of steps are performed can be used in various ways.

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 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. The grounding state formed by being electrically connected to the centralized grounding terminal in which the protective grounding conductors 201 are arranged together with the centralized grounding terminal in place of the protective grounding conductor is described above. The steps of the embodiment shown in any one of the first to seventh embodiments are performed and confirmed.

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.

Instead 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 steps 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 in one step without performing a series of steps for each of the protective ground conductors 201.

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, when confirming in more detail whether or not the grounding system is in a normally functioning state, the state in which the B-type grounding and the D-type grounding are normally performed is regarded as a basic state, and the above-mentioned basic state is described. When the measurement current value and the measurement voltage value shown in the embodiment described above are stored in the storage unit as basic data and the process is repeated over time, the obtained measurement current value and measurement voltage value By comparing the data with the basic data, it is determined whether or not there is a deviation from the normal state, and if the deviation becomes a predetermined magnitude, the grounding state is functioning normally. It can be determined that they have not.

In addition, the resistance value data in the grounding system is actually obtained from the basic data, and the resistance value data is obtained from the measured current value and the measured voltage value data obtained as a result of repeating the process over time. When the deviation of each resistance value data becomes a predetermined magnitude, it can be determined that the grounding state is not functioning normally.

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 determined whether or not the ground resistance value is within 100Ω in the case of class D grounding work described in the technical standards for electrical equipment. If the ground resistance value is larger than the ground resistance value, the grounding state is normal. It can be determined that it is not functioning.

Further, the ground state confirmation device 300 is provided with a communication unit, and the above basic data, the measured current value and the measured voltage value data obtained by repeating the above-mentioned process over time, and these data are obtained. Whether the installation status is functioning normally on the external device by making it possible to obtain the obtained resistance value data and data such as whether the grounding status is normal on the external device. It can be confirmed.

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 power 10002 data 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. In addition, the data obtained by the grounding state confirmation device 300 is accumulated on a data storage server provided on the Internet via the gateway device and the Internet network, and the power company side accesses the data storage server. Then, it may be possible to confirm whether or not the grounding state is functioning normally by referring to data from the grounding state confirmation device 300 as a target.

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. When it exceeds or when 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 so that the grounding state becomes normal.

In addition, the ground state confirmation device 300 is provided with a notification unit, and the above basic data, the measured current value and the measured voltage value data obtained by repeating the above-mentioned process over time, and these data are obtained. If the resistance value data or the data indicating whether the grounding state is normal exceeds a predetermined value or greatly deviates, the notification unit indicates that the grounding state is not normal. This may be notified so that the grounding state can be confirmed in the surroundings.

In addition, two-way communication is performed between the server on the power company side and the ground state confirmation device 300, and the ground state grasped on the power company side is notified from the notification unit, so that the grounding is performed. The state of can be confirmed more appropriately.

For the sound data to be notified, a microcomputer may be provided in the ground state confirmation device 300, and an assumed sound may be stored in the microcomputer in advance. Alternatively, the voice data may be transmitted to the communication unit of the ground 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 a method 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 it can be confirmed.

Explanatory drawing of the method of confirming the state of grounding according to the first embodiment Explanatory drawing of the method of confirming the state of grounding according to the second embodiment Explanatory drawing of the method of confirming the state of grounding according to the third embodiment Explanatory drawing of the method of confirming the state of grounding according to the fourth embodiment Explanatory drawing of the method of confirming the state of grounding concerning the fifth embodiment Explanatory drawing of the method of confirming the state of grounding according to the sixth embodiment Explanatory drawing of the method of confirming the state of grounding concerning a 7th embodiment Explanatory drawing of the method of confirming the state of grounding concerning an 8th embodiment Illustration of ground voltage and ground resistance when insulation of load equipment installed in electric circuit deteriorates

DESCRIPTION OF SYMBOLS 1 Earth 100 Transformer 101 Voltage line 102 Neutral line 103 1st electrical terminal 201 Protective ground conductor 202 Ground line 203 2nd electrical terminal 300 Ground state confirmation apparatus 301 Power supply apparatus 302 Current measurement means 303 Determination part 304 Voltage Measuring means 401 Switching means 501 Repeat confirmation means 601 Centralized ground terminal

Claims (2)

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 means for separating / connecting the plurality of protective ground conductors and the ground wire;
A step of controlling on / off of the switch means;
In each case where the switch means is in the on state and the off state
Applying a voltage between a ground-side wire in the load-side circuit and the protective ground conductor;
And detecting a current flowing between the protective earth conductor and said ground side electric wire,
Comparing the current value obtained when the switch means is on with the current value obtained when the switch means is off;
A step of determining that the grounding system is connected when there is a change in the current value as a result of the comparison;
And a step of determining that the ground system is not connected when the current value does not change as a result of the comparison . In the grounding system,
Grounding system connection status confirmation method according to claim 1, characterized by comprising the step of performing a series of steps of the described at predetermined time intervals.

Images