KR20230061805A - Device for limiting interphase current and leakage current of flooded electric facilities - Google Patents

Abstract

The present invention relates to a three-phase and four-wire phase-to-phase current and leakage current limiting device for flooded electrical equipment which is implemented to limit phase-to-phase current and leakage current between three-phase lines when electrical equipment is flooded so as to reduce current flowing through a human body that comes into contact with leaked electricity, thereby efficiently preventing electric shock accidents.

Description

Device for limiting interphase current and leakage current of flooded electric facilities}

The present invention relates to phase-to-phase current and leakage current limiting technology. In particular, when a three-phase, four-wire electrical facility is submerged in water, water vapor, or other highly conductive fluid, the phase-to-phase current between the three-phase lines in the electrical facility passes through the highly conductive liquid. A 3-phase 4-wire type phase-to-phase current and leakage current limiting device for a submerged electrical facility that prevents electric equipment from being damaged due to a rapid increase and limits the leakage current flowing from the 3-phase line to the ground through the liquid to prevent an electric shock accident will be.

Electric shock is a phenomenon in which the human body reacts when the leakage current flowing from the power source through the human body to the ground, which is the ground plane, exceeds a certain value. In general, convulsions occur when leakage current exceeds 15mA, and death occurs when leakage current exceeds 50mA. The leading cause of death is heart failure, in which the heart stops working as the current flowing through the heart damages the nerves. The risk of electric shock is related to the resistance of the human body at the time of energization, which greatly depends on the condition of the skin.

When electrical equipment such as electrical outlets, electric heaters, or lights are submerged in water and the human body contacts the water or a metal housing that is energized through the water, the exposed conductor of the electrical equipment passes through the water and the human body. current flows through the ground At this time, the human body is in a very dangerous state because the skin is easy to get wet in the rain and in that case the contact resistance is extremely low.

A short circuit between power lines is a problem that causes damage to equipment such as fire or short circuit in electrical equipment by rapid current flow when the insulation level between the two lines is lowered and the electrical conductivity is increased. In general, the insulation of air is very high, so air is used as a medium to maintain electrical insulation between two wires. However, when a fluid with high electrical conductivity is filled between the two lines due to flooding or the like, the current between the three phases increases rapidly, resulting in a short circuit.

Republic of Korea Patent Publication No. 10-2005-0037986 (published on April 25, 2005, hereinafter referred to as "the first prior art") is to attach a metal plate or metal mesh to a bare charging part to prevent current leaking from the bare charging part when submerged. Disclosed is a submersion electric shock prevention device that is energized through a conductive metal plate or metal mesh to prevent an electric shock accident. The metal plate or metal mesh is connected to a neutral wire and a ground terminal among terminal blocks by wires. The size of the metal plate is approximately 50 cm × 30 cm.

The first prior art does not explain the principle in detail, but it is possible to arrange a metal plate in a state in which the resistance is much lower than the resistance through water and the human body between submerged conductors when flooded, and electrically configured in parallel with the human body. appears to limit the current flowing to However, such a metal plate or metal mesh cannot effectively block a leakage current because it cannot shield an electric field radially generated from a bare charging unit, and thus, space limitations occur in installation. In addition, the first prior art mentions the leakage current, but does not mention the three-phase current.

Republic of Korea Patent Registration No. 10-1197414 (published on November 5, 2012, hereinafter "Second Prior Art") discloses another earth leakage prevention device. The apparatus of the second prior art is disposed between the input terminal unit and the output terminal unit and electrically connects to a connection terminal block in which first and second connection terminals connected to a neutral point terminal and a three-phase voltage terminal are installed, and a first connection terminal connected to the neutral point terminal. It is connected to and has a shape that surrounds the side and top of the connection terminal block, and includes a leakage-preventing conductor that allows only the current generated from the three-phase voltage terminal to flow to the enclosed neutral point terminal.

As shown in the representative diagram of the second prior art, the neutral point terminal (N) of the three-phase power supply is not grounded, so that a closed circuit in which leakage current due to electric leakage will flow is not formed. Therefore, in the conductor of the second prior art in any form, leakage current cannot flow to the ground or the like.

In addition, even if the neutral point of the three-phase power supply is grounded and a path through which leakage current flows is formed, the current flowing through the neutral wire is very low when the three-phase power supply is electrically balanced, but becomes large when the three-phase power supply is electrically unbalanced. However, since there is no structure to shield the current generated through the neutral wire, leakage current inevitably flows.

Moreover, due to the conductive fluid filled between the phase voltage terminal and the neutral point terminal in a very narrow space in the leakage protection device, the resistance becomes very small, and as a result, the current rises rapidly, increasing its absolute value in the distribution of the neutral current and the ground current. let it The increase in leakage current due to this has a limit that cannot be prevented by the device of the second prior art.

That is, the ground voltage of the neutral point terminal is very low when the 3-phase power is electrically balanced, but when the 3-phase power is electrically unbalanced or the length of the line is long, it has line impedance or the ground resistance of the neutral point is that of soil or building. If the grounding resistance is high due to the material, etc., the ground voltage increases. Therefore, in the second prior art, the leakage current generated from the phase voltage terminal can flow to the neutral point terminal, but the leakage current generated from the neutral point terminal flows to the ground, so that electric shock cannot be prevented.

In addition, the second prior art mentions a detailed technique for the configuration of a complicated automation system that automatically finds a three-phase voltage terminal and a neutral point terminal, and one found terminal is a three-phase voltage terminal and the other is a three-phase voltage terminal. It only describes that it is connected to the neutral point terminal surrounding the terminal, so there is a disadvantage that it is difficult to apply it in practice because it cannot provide a basis for why there is no leakage.

In addition, the automation system that automatically finds the three-phase voltage terminal and the neutral point terminal has a disadvantage in that the configuration is complicated and the life of the product is very short, so that its practical application is very limited. Moreover, since the second prior art uses an electrode having a shape connected to the neutral point terminal while surrounding the connection terminal block, the configuration is complicated, and it is difficult to apply to a small outlet or the like.

In addition, the second prior art mentions a technique for preventing leakage current, but does not mention the limitation of current between three phases.

Republic of Korea Patent Registration No. 10-1441366 (published on September 23, 2014, hereinafter "Third Prior Art"), previously filed and registered by the applicant of the present invention, discloses a device for limiting phase current and leakage current of flooded electrical equipment, there is.

The third prior art describes limiting the phase-to-phase current and leakage current between the single-phase phase voltage line and the neutral line, but does not describe the phase-to-phase current and leakage current limit between the phase lines when the three-phase, four-wire electrical equipment is flooded.

Republic of Korea Patent Publication No. 10-2005-0037986 (published on April 25, 2005) Republic of Korea Patent Registration No. 10-1197414 (2012. 11. 05 announcement) Republic of Korea Patent Registration No. 10-1441366 (Announced on September 23, 2014)

The present invention was invented to solve the above problems, and in particular, the structure is simple, the installation is simple, and the three-phase of the flooded electrical equipment can limit the rapid rise of the electrical equipment to prevent electric shock. Its purpose is to provide a 4-wire phase-to-phase current and leakage current limiting device.

In addition, another object of the present invention is to provide a three-phase, four-wire, phase-to-phase current and leakage current limiting device for submerged electrical equipment that can be applied to various application fields employing three-phase, four-wire electrical equipment.

According to one aspect of the present invention for achieving the above object, a three-phase four-wire phase current and leakage current limiting device of a submerged electrical facility is connected to a distribution line of the electrical facility, and the electrical facility or the electrical facility is electrically to prevent electric shock in the event of flooding of other electrical facilities located nearby, but at one end, three-phase line terminals (12a, 12b, 12c) electrically connected to the three-phase lines (2a, 2b, 2c) of the distribution line, respectively ), and internal phase lines 32a, 32b, and 32c having phase line portions 22a, 22b, and 22c that are electrically connected to the electrical equipment 200 at the other end thereof and not surrounded by an insulator; One end has neutral wire terminals 14a, 14b, 14c electrically connected to the neutral wire 4 of the distribution line, and the other end is electrically connected to the electrical equipment 200 and the phase line parts 22a, 22b, 22c ) And internal neutral wires (34a, 34b, 34c) electrically connected to the tubular lines (26a, 26b, 26c) of a conductive material surrounding the conductor, respectively; One end portion has ground wire terminals 16a, 16b, and 16c electrically connected to the ground wire 6 of the distribution line, and the other end portion is electrically connected to the electrical equipment 200, formed of an insulator, and a tubular line 26a , 26b, 26c) and internal ground wires (36a, 36b, 36c) electrically connected to housing grounds (28a, 28b, 28c) provided with ground wires on the inner circumferential surface of the housing, respectively; Insulation cylinders 24a, 24b, 24c are disposed between the inner phase lines 32a, 32b, and 32c and the tubular lines 26a, 26b, and 26c and surround the inner phase lines 32a, 32b, and 32c, respectively. do.

According to an additional aspect of the present invention, the tubular lines 26a, 26b, and 26c extend in both directions from both ends of the phase line portions 22a, 22b, and 22c, and the insulating tubes 24a, 24b, and 24c are the phase lines. It extends in both directions from both ends of the parts 22a, 22b, and 22c and the tubular lines 26a, 26b, and 26c, and the housing grounds 28a, 28b, and 28c extend in a positive direction from both ends of the tubular lines 26a, 26b, and 26c. It can be implemented to extend in the direction.

According to an additional aspect of the present invention, a terminal connection check circuit (20a, 20b) electrically connected between the neutral wire terminals (14a, 14b, 14c) and the ground wire terminals (16a, 16b, 16c), a resistor and an LED are connected in series , 20c) may be further included.

According to an additional aspect of the present invention, the length of the passage between the inner phase lines 32a, 32b, 32c and the inner neutral wires 34a, 34b, 34c is increased by adjusting the length of the insulation tubes 24a, 24b, 24c, or , The area of the phase line parts 22a, 22b, and 22c may be adjusted to increase the resistance between the phase line parts 22a, 22b, and 22c and the tubular lines 26a, 26b, and 26c to limit the current between phases. .

According to an additional aspect of the present invention, the current flowing through the barrel lines 26a, 26b, 26c due to the sum of the limited phase-to-phase current and the on-current from the electric load to the internal neutral wires 34a, 34b, 34c is reduced to the housing ground 28a, 28b. , 28c) through the internal ground lines 36a, 36b, and 36c to flow to the ground, thereby limiting the leakage current.

Since the present invention can limit the phase current and leakage current between three-phase lines when electrical equipment is flooded through a three-phase, four-wire type phase current and leakage current limiting device of a submerged electrical equipment that has a simple structure and is easy to install, It is possible to reduce the current flowing through the human body in contact with the exposed electricity, which has the effect of effectively preventing an electric shock accident.

In addition, according to the present invention, the length of the passage between the inner three-phase line and the inner neutral is increased by adjusting the length of the insulation tube inserted between the inner three-phase line and the inner neutral, or the area of the three-phase line is adjusted to increase the three-phase line. There is an effect of limiting the current between the three phases by increasing the resistance between the part and the tubular line.

In addition, according to the present invention, the limited three-phase current and the current from the electric load to the internal neutral wire are combined to allow the current flowing through the tubular line to flow through the housing ground through the internal ground wire to the ground, thereby limiting the leakage current.

In addition, according to the present invention, by connecting a terminal connection check circuit of a very simple structure in which a resistor and an LED are connected in series between the neutral terminal and the ground terminal at the entrance of the electrical terminal, the effect of inducing the correct connection between the electrical terminal terminal and the power line there is

In addition, since the present invention can be applied to various application fields employing three-phase, four-wire electrical equipment, there is an excellent effect in versatility.

1 is a schematic diagram of a three-phase four-wire phase current and leakage current limiting device for a submerged electrical installation according to the present invention.
Figure 2 is a diagram showing the configuration of an embodiment of a three-phase four-wire phase current and leakage current limiting device for a submerged electrical installation according to the present invention.
Fig. 3 is an equivalent circuit diagram of Fig. 2;
4 is a diagram illustrating a human body accessing a submerged electrical facility in which a three-phase, four-wire phase current and leakage current limiting device of a submerged electrical facility according to the present invention is installed.
Fig. 5 is an equivalent circuit diagram of Fig. 4;
6 is a view for explaining experimental conditions for testing the effect of preventing electric shock to a human body when a submerged electrical facility is flooded with a three-phase, four-wire phase-to-phase current and leakage current limiting device installed according to the present invention.
7 is a view for explaining human body contact during flooding of an electrical facility in which a three-phase, four-wire phase current and leakage current limiting device of a submerged electrical facility according to the present invention is installed.

Hereinafter, the present invention will be described in detail so that those skilled in the art can easily understand and reproduce the present invention through preferred embodiments described with reference to the accompanying drawings. Although specific embodiments are illustrated in the drawings and related details are described, they are not intended to limit the various embodiments of the present invention to any particular form.

In describing the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the gist of the embodiments of the present invention, the detailed description will be omitted.

It is understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, but other elements may exist in the middle. It should be.

On the other hand, when a component is referred to as “directly connected” or “directly connected” to another component, it should be understood that no other component exists in the middle.

First, the theoretical basis and terminology of the three-phase four-wire phase current and leakage current limiting device of the submerged electrical equipment according to a preferred embodiment of the present invention are defined. In the equilibrium state of the natural world, positive and negative charges are equal, so it appears that there is no charge. However, when a force is applied to an atom to separate the positive and negative charges, the charge (Q) appears to be created only then.

An electric field (E) is when a force is applied to an atom and charges appear, and the applied energy is converted into electrical energy and distributed around the charges. At this time, the electric field is a vector that originates from the positive charge and goes to the negative charge.

The magnetic field (H) is when a force is applied to the charge to move the charge (that is, when it becomes a current), the applied energy is distributed as magnetic energy around the current. At this time, the magnetic field is a vector rotating around the current.

The electric field and the magnetic field always occur together. That is, a magnetic field is generated by an electric field, or an electric field is generated by a magnetic field, and this is an electromagnetic phenomenon. At this time, the electric and magnetic fields have orthogonal vector directions.

Direct current or low-frequency current (several Hz or kHz) can be interpreted as an electrostatic field or a magnetostatic field. However, currents with high frequencies, such as those in the MHz or GHz bands, must be interpreted as electromagnetic.

The current density (J) is defined as the electric field (E) and the conductivity (σ) of the surrounding medium, and has the following relationship.

Here, J and E are vector quantities.

At this time, the direction of the current density is the vector direction of the electric field. Integrating the current density gives the current (I).

The resistance (R) of a passage through which current flows has the following relationship with respect to the length (ℓ) and the cross-sectional area (S) of the passage.

The current flowing through this resistance has the following relationship with the voltage.

Therefore, the current can be limited by increasing the resistance by increasing the length or reducing the area of the passage.

The AC power generated in the power plant is three powers (Three Phase Power) having a phase difference of 120 degrees each (total of 36a, 36b, and 36c0 degrees) electrically and spatially.

In general, in a 3-phase 4-wire distribution line, one phase is selected among 3-phase power (single-phase power) and a common line (neutral line) is shared.

In the neutral wire, the three currents flowing in the three-phase power flow in common. However, these three currents electrically have a phase difference of 120 degrees.

At this time, if the three currents are the same (if the same load is applied to the three phases), the vector sum of the three currents is 0, so the current does not appear to flow.

However, since the three currents are not equal because it is difficult to apply the same load to the three phases, the vector sum of the three currents is unlikely to be zero. That is, it appears that current flows through the neutral wire.

That is, in the distribution line, a three-phase AC circuit is formed and connected so that the ends of each lead line of the three single-phase systems form one neutral point. When the loads of a three-phase system are balanced, no current flows in the neutral wire. However, in most cases, an unbalanced load is connected, and in this case, a smaller neutral current flows than a line current (Source: Power Transmission Engineering, Lee Bong-yong, Moon Woon-dang, p.13~17)

Although the three-phase line and the neutral line are made of low-resistance conductors, they have their own impedance because the length is long and these lines are meanderingly arranged.

The ground line refers to a line connected to the ground (Earth).

Leakage current refers to current flowing through a path other than a three-phase line or neutral line, and ground fault current or earth current flows due to low resistance between a three-phase line or neutral line and the ground. means current.

Electric shock is an accident caused by current flowing from a three-phase line or neutral line through the human body (the human body has high conductivity) to the ground. Since the leakage current flows through the human body to the ground and becomes the ground current, the leakage current causes electric shock.

Interphase current refers to the current between one phase and neutral. Since an electric shock accident occurs when an interphase current flows to a human body through water due to immersion, etc., a three-phase current also causes an electric shock, as well as a leakage current.

Based on the above-mentioned electrical matters as a theoretical basis, the present invention discloses a three-phase, four-wire phase current and leakage current limiting device for submerged electrical equipment.

1 is a schematic diagram of a three-phase, four-wire, phase-to-phase current and leakage current limiting device for a submerged electrical installation according to the present invention. The three-phase, four-wire, phase-to-phase current and leakage current limiting device 100 of a submerged electrical facility according to the present invention is connected to the distribution line of the electrical facility 200 and electrically connected to the electrical facility or the electrical facility to be nearby. Prevent electric shock in case of flooding of other electrical facilities located.

As shown in FIG. 1, the three-phase four-wire phase current and leakage current limiting device 100 of the flooded electrical equipment according to this embodiment includes internal phase lines 32a, 32b, and 32c, an internal neutral wire 34a, 34b, 34c), internal ground lines 36a, 36b, 36c, and insulating cylinders 24a, 24b, 24c.

The internal phase lines 32a, 32b, and 32c have three-phase line terminals 12a, 12b, and 12c electrically connected to the three-phase lines 2a, 2b, and 2c of the distribution line at one end, and the other end are electrically connected to the electrical equipment 200 and have phase line units 22a, 22b, and 22c that are not surrounded by an insulator.

The inner neutral wires (34a, 34b, 34c) have neutral wire terminals (14a, 14b, 14c) electrically connected to the neutral wire (4) of the distribution line at one end, and the other end is electrically connected to the electrical equipment (200). and are electrically connected to the cylindrical lines 26a, 26b, and 26c made of a conductor material surrounding the phase line parts 22a, 22b, and 22c, respectively.

The internal ground lines (36a, 36b, 36c) have ground wire terminals (16a, 16b, 16c) electrically connected to the ground wire (6) of the distribution line at one end, and the other end is electrically connected to the electrical equipment (200). It is formed of an insulator and is electrically connected to the housing grounds 28a, 28b, and 28c having ground wires on the inner circumferential surface of the housing surrounding the tubular lines 26a, 26b, and 26c, respectively.

At this time, the tubular lines 26a, 26b, and 26c extend in both directions from both ends of the phase line portions 22a, 22b, and 22c, and the insulated tubes 24a, 24b, and 24c are phase line portions 22a, 22b, 22c) and extends in both directions from both ends of the tubular lines 26a, 26b, and 26c, and the housing grounds 28a, 28b, and 28c extend in both directions from both ends of the tubular lines 26a, 26b, and 26c. can

Insulation cylinders 24a, 24b, and 24c are disposed between the inner phase lines 32a, 32b, and 32c and the tubular lines 26a, 26b, and 26c, respectively, and surround the inner phase lines 32a, 32b, and 32c, respectively.

At this time, the length of the passage between the internal phase lines 32a, 32b, 32c and the internal neutral wires 34a, 34b, 34c is increased by adjusting the length of the insulation tubes 24a, 24b, 24c, or the phase line unit 22a , 22b, 22c) to increase the resistance between the phase line parts 22a, 22b, 22c and the tubular lines 26a, 26b, 26c to limit the current between phases.

On the other hand, the current flowing through the tubular lines 26a, 26b, 26c due to the sum of the limited phase-to-phase current and the on-current from the electric load to the internal neutral wires 34a, 34b, and 34c is the internal ground wire through the housing grounds 28a, 28b, and 28c. It can be implemented to limit the leakage current by flowing to the ground through (36a, 36b, 36c).

On the other hand, the three-phase four-wire phase current and leakage current limiting device 100 of the submerged electrical equipment may further include terminal connection check circuits 20a, 20b, and 20c. The terminal connection check circuits 20a, 20b, and 20c are electrically connected between the neutral wire terminals 14a, 14b, and 14c and the ground wire terminals 16a, 16b, and 16c, and a resistor and an LED are connected in series.

(1) Guidance of correct connection of distribution lines of electric facilities

By distinguishing the three-phase lines (2a, 2b, 2c) and the neutral wire (4) of the distribution line of the electrical facility, the three-phase four-wire phase current and leakage current limiting device 100 of the submerged electrical facility according to the present invention It should be properly connected to the line terminals (12a, 12b, 12c) and the neutral wire terminals (14a, 14b, 14c).

To this end, a terminal between the neutral wire terminals 14a, 14b, 14c and the ground wire terminals 16a, 16b, 16c at the entrance of the three-phase four-wire phase current and leakage current limiting device 100 of the submerged electrical equipment according to the present invention The connection check circuits 20a, 20b and 20c are connected. The terminal connection check circuits 20a, 20b, and 20c have a very simple structure in which resistors and LEDs are connected in series.

If the three-phase lines (2a, 2b, 2c) of the distribution line of the electrical equipment are flooded according to the present invention, the neutral terminals (14a, 14b, When connected to 14c), the LEDs of the terminal connection check circuits 20a, 20b, and 20c light up to indicate that the terminal connection is incorrect.

On the other hand, when the neutral wire 4 of the distribution line of the electrical equipment is connected to the neutral terminals 14a, 14b, 14c of the three-phase four-wire phase current and leakage current limiting device 100 of the submerged electrical equipment according to the present invention, the LED does not light up so that it can be judged that it is connected correctly.

The ground line terminals 16a, 16b, and 16c of the three-phase, four-wire phase current and leakage current limiting device 100 of the submerged electrical equipment according to the present invention are connected to the ground line 6.

(2) Formation of phase current

In order to distinguish from the three-phase lines (2a, 2b, 2c) and the neutral wire (4) and the ground wire (6) of the distribution line of the electrical installation, the three-phase four-wire phase current and leakage current limit of the submerged electrical installation according to the present invention Within device 100, internal phase lines 32a, 32b, 32c, internal neutral wires 34a, 34b, 34c and internal ground wires 36a, 36b, 36c are defined.

The inner phase lines 32a, 32b, and 32c have three-phase line terminals 12a, 12b, and 12c at one end, and the other end is electrically connected to the electrical equipment 200.

The inner neutral wires (34a, 34b, 34c) have neutral wire terminals (14a, 14b, 14c) at one end, and the other end is electrically connected to the electrical equipment (200).

The internal ground lines (36a, 36b, 36c) have ground wire terminals (16a, 16b, 16c) at one end, and the other end is electrically connected to the electrical equipment (200).

In the three-phase, four-wire phase-to-phase current and leakage current limiting device 100 of the flooded electrical equipment according to the present invention, the internal phase lines (32a, 32b, 32c), the internal neutral wire (34a, 34b, 34c) and the internal ground wire (36a) , 36b, 36c) are placed.

Among the internal phase lines 32a, 32b, and 32c, the phase line parts 22a, 22b, and 22c, which are not surrounded by insulators, and the phase line parts 22a, 22b, and 22c are surrounded but the internal neutral wires 34a, 34b, and 34c ) and the tubular lines 26a, 26b, and 26c electrically connected, and the housing grounds 28a, 28b, and 28c electrically connected to the internal ground lines 36a, 36b, and 36c while surrounding the tubular lines 26a, 26b, and 26c. ) is placed. At this time, insulating tubes 24a, 24b, and 24c are interposed between the phase line portions 22a, 22b, and 22c and the tubular lines 26a, 26b, and 26c.

The housing grounds 28a, 28b, and 28c are basically housings made of an insulator, and ground wires are connected to their inner circumferential surfaces, and these ground wires are electrically connected to internal ground wires 36a, 36b, and 36c.

The material of the tubular lines 26a, 26b and 26c is constituted by a conductor. The tubular lines 26a, 26b, and 26c and the housing grounds 28a, 28b, and 28c may be configured as coaxial tubs (tubs having the same axis), and it does not matter if they are not coaxial.

The tubular lines 26a, 26b, and 26c are long tubular conductors having a closed curve in cross section. 1, as an example, it is shown as a conductor (coaxial cylindrical line) in the form of a long cylindrical tube with an empty middle, but is not limited thereto, and if it is in the form of a closed curve that completely surrounds the phase line parts 22a, 22b, and 22c, a polygonal tube, Various shapes such as a concave polygonal cylinder and an elliptical cylinder are possible.

The phase line units 22a, 22b, and 22c are inserted into the tubular lines 26a, 26b, and 26c, and may be long tubular or lumpy rod-shaped conductors having various cross-sectional shapes. However, the present invention is not limited thereto, and may be a polygonal tubular shape or a solid polygonal rod shape.

The tubular lines 26a, 26b, and 26c surround the phase line portions 22a, 22b, and 22c that are not surrounded by an insulator, and are electrically connected to the inner neutral wires 34a, 34b, and 34c. At this time, the height and length of the tubular lines 26a, 26b, and 26c are the same as the phase line parts 22a, 22b, and 22c, or longer than the phase line parts 22a, 22b, and 22c. It is preferable to extend in both directions longer than both ends of 22a, 22b and 22c).

The housing grounds 28a, 28b, and 28c surround the tubular lines 26a, 26b, and 26c and are electrically connected to the internal ground lines 36a, 36b, and 36c. At this time, the height and length of the housing grounds 28a, 28b, and 28c are equal to the height and length of the tubular lines 26a, 26b, and 26c, or the tubular lines are longer than the tubular lines 26a, 26b, and 26c. It is preferable to extend in both directions longer than both ends of (26a, 26b, 26c).

Theoretically, since the diverging electric fields started from the phase line portions 22a, 22b, and 22c all end at the cylindrical lines 26a, 26b, and 26c connected to the internal neutral wires 34a, 34b, and 34c, the electric field cannot escape to the outside. .

In addition, when the three phases are unbalanced, current also flows in the internal neutral wires 34a, 34b, and 34c, and the electric field started from the tubular lines 26a, 26b, and 26c connected to these internal neutral wires 34a, 34b, and 34c is partially phased. Since it goes to the line parts 22a, 22b, and 22c, and the rest goes to the housing grounds 28a, 28b, and 28c connected to the internal ground lines 36a, 36b, and 36c, there is no electric field escaping to the outside. When there is no electric field escaping to the outside, a current between phases is formed by integrating the current density according to Equation 1.

In practice, the system is housed with housing grounds 28a, 28b, 28c, which are insulators surrounding the inner neutral wires 34a, 34b, 34c, and the inner ground wires 36a, 36b, 36c are connected to the housing grounds 28a, 28b, 28c. connect to

(3) Limitation of phase-to-phase current

Insulation tubes 24a, 24b, and 24c are interposed between the phase line portions 22a, 22b, and 22c and the tubular lines 26a, 26b, and 26c. At this time, the height and length of the insulated tubes 24a, 24b, and 24c are the same as those of the phase line parts 22a, 22b, and 22c and the tubular lines 26a, 26b, and 26c, or the phase line parts 22a, 22b, and 22c It extends in both directions longer than both ends of the phase line portions 22a, 22b, 22c and the tube lines 26a, 26b, and 26c so as to be longer than the tube and tube lines 26a, 26b, and 26c.

Preferably, the insulating cylinders 24a, 24b, and 24c extend longer than both ends of the phase line parts 22a, 22b, and 22c so that the phase line parts 22a, 22b, and 22c can be completely inserted therein, It extends longer than both ends of the tubular lines 26a, 26b, and 26c so as to completely block between the line portions 22a, 22b, and 22c and the tubular lines 26a, 26b, and 26c. For example, the height and length may be formed in the order of phase line portions 22a, 22b, and 22c < tubular lines 26a, 26b, and 26c < insulating tubs 24a, 24b, and 24c.

The insulated cylinders 24a, 24b, and 24c may be formed in various cylindrical shapes such as a cylinder, an elliptical cylinder, and a rectangular cylinder, and are coaxial with the phase line portions 22a, 22b, and 22c and the cylindrical lines 26a, 26b, and 26c. It doesn't matter if it is or not coaxial.

When seawater or fresh water containing various minerals is filled in the narrow gap between the phase line parts 22a, 22b, and 22c and the tubular lines 26a, 26b, and 26c, the conductivity (σ) is high and the gap (ℓ) according to Equation 2 ) is also very small, so the resistance R is very low, and a very large three-phase current is generated as shown in Equation 3.

Therefore, the length (ℓ) of the passage between the three-phase line and the neutral line by filling the insulator cylinders 24a, 24b, and 24c made of an insulator between the phase line parts 22a, 22b, and 22c and the tubular lines 26a, 26b, and 26c. The current between the three phases can be limited by increasing the resistance R by increasing or appropriately adjusting the area S of the phase line parts 22a, 22b and 22c, which are the peeled parts of the three phase line.

(4) Limitation of leakage current

The current from the electric load is combined with the limited three-phase current described in item (3), flows through the internal neutral wires (34a, 34b, 34c), and leaks out of the housing ground (28a, 28b, 28c) is allowed to flow to the ground through the grounding wire 6, thereby maintaining safety by maximally suppressing the leakage current flowing to the human body to prevent an electric shock accident.

The three-phase, four-wire, phase-to-phase current and leakage current limiting device for flooded electrical equipment according to the present invention is connected to the transmission and distribution path to household or industrial electric equipment such as lamps, streetlights, outlets, plugs, and motors, and electrical equipment to which this device is connected. Or it is electrically connected to the electrical facility to prevent electric shock in the event of flooding of other electrical facilities located nearby.

The three-phase, four-wire phase-to-phase current and leakage current limiting device for flooded electrical equipment according to the present invention includes phase line parts 22a, 22b, 22c, tubular lines 26a, 26b, 26c and housing grounds 28a, 28b, 28c ) can be installed in a standing state facing each other, and it is preferable to install it at a lower position than the target electrical equipment to be protected from flooding.

For example, in the case of a street light, the controller exposed at the bottom is installed in a waterproof space, but when rainwater fills the space, people around it are at risk of electric shock. The three-phase, four-wire, phase-to-phase current and leakage current limiting device of the submerged electrical equipment according to the present invention is installed in this waterproof space and is installed at a lower position than the controller, so that the controller is submerged earlier than the time of flooding, so that it can operate first. do.

The phase line units 22a, 22b, and 22c and the tubular lines 26a, 26b, and 26c may be formed of a copper (Cu) material having good conductivity. According to the experiment, the effect of preventing electric shock was better when the material was copper than when the material was iron or aluminum.

FIG. 2 is a diagram showing the configuration of an embodiment of a three-phase, four-wire, phase-to-phase current and leakage current limiting device for a submerged electrical installation according to the present invention, and FIG. 3 is an equivalent circuit diagram of FIG. 2 .

Referring to FIGS. 2 and 3 , resistance R1 through water is formed between the three-phase line R and the neutral line N by an insulating cylinder 24a. In addition, resistance R2 through water is formed between the three-phase line S and the neutral line N by the insulation cylinder 24b. Between the three-phase line T and the neutral line N, resistance R3 through water is formed by the insulating tube 24c.

Between the three-phase line N and the ground line G, a resistance R4 through water and ground is formed by the insulating tube of the housing ground 28a. At this time, since the neutral line N surrounds the three-phase line R by the tubular line 26a, all electric fields generated in the three-phase line R are directed toward the neutral line N, and a circuit between the three-phase line R and the neutral line N is formed. Since the circuit from the three-phase line R to the ground line G is not formed, resistance R4 is formed between the neutral line N and the ground line G.

Since the neutral line N surrounds the three-phase line S by the tubular line 26b, all electric fields generated from the three-phase line S are directed toward the neutral line N, and a circuit between the neutral line N outside the three-phase line S is formed. Since a circuit from the line S phase to the ground line G is not formed, a resistance R4 is formed between the neutral line N and the ground line G.

Since the neutral line N surrounds the two-phase line S by the tubular line 26c, the electric field generated in the three-phase line S is all directed toward the neutral line N, and a circuit between the neutral line N outside the three-phase line S is formed, but the three-phase line S Since no circuit is formed from to the blocking line G, a resistance R4 is formed between the neutral line N and the ground line G.

On the other hand, in the second prior art mentioned in the background of the invention, the insulating tube is not interposed between the three-phase line R and the neutral line N, so that the three-phase line R and the neutral line N are shorted or extremely low resistance is formed, resulting in excessively large Phase-to-phase current occurs, and since the absolute value of leakage current, which will be described in the current distribution circuit below, becomes large, safety (prevention of electric shock accidents) cannot be guaranteed. The same is true between the three-phase line S and the neutral line N, and between the three-phase line T and the neutral line N.

On the other hand, in the third prior art mentioned in the background of the invention, an insulating tube is interposed between the three-phase line R and the neutral line N, but between the three-phase line S and the neutral line N, and between the three-phase line T and the neutral line N. However, in the case of the present invention, the phase-to-phase current and leakage current for all phase lines of the 3-phase 4-line Leakage current can be limited.

4 is a diagram illustrating a human body approaching when a three-phase, four-wire phase-to-phase current and leakage current limiting device is installed in a submerged electrical facility according to the present invention is flooded, and FIG. 5 is an equivalent circuit diagram of FIG.

In FIG. 5, R1, R2, and R3 are phase-to-phase resistance components, and R4 and R5, R8 and R9, and R10 and R11 are resistance components and inductance of the line when the electric line is long (most distribution lines actually installed are long) It is the resistive component of the impedance composed of components. And, R6 is ground resistance, R7 is resistance formed through human body resistance, water resistance and earth resistance when a person approaches.

When the three-phase four-wire phase-to-phase current and leakage current limiting device 100 of the submerged electrical facility according to the present invention is installed in the electrical facility 200 and is flooded, the current with the resistance R1 formed between the three-phase line R and the neutral line N i2 flows, current i6 flows through the resistance R2 formed between the three-phase line S and the neutral line N, current i10 flows through the resistance R3 formed between the three-phase line T and the neutral line N, and currents i3 and i7 in each phase through the electric load , i11 flows and merges at point P of each phase. These combined currents are divided into i4, i8, and i12 in the N phase, i13 in the G phase, and leakage currents i14a, 14b, and 14c.

At this time, the distributed currents i4, i8, i12, i13, i14a, 14b, and 14c are distributed in inverse proportion to the resistors R5, R9, R11, R6, and R7 as shown in the equation below.

In general, resistances R5, R9, and R11 of neutral wire N are very small, so most of the current becomes i4, i8, and i12. In addition, since R6 and R7 have relatively large values compared to R5, R9, and R11, i13, i14a, 14b, and 14c are reduced to suppress leakage currents i14a, 14b, and 14c.

The key to suppressing leakage current in the present invention is as follows. The current distribution by resistance value between 3-phase line R and neutral line N, between 3-phase line S and neutral line N, and between 3-phase line T and neutral line N is the same.

(1) Between 3-phase line R and neutral line N, between 3-phase line S and neutral line N, and between 3-phase line T and neutral line N, place an insulation tube to increase the phase-to-phase resistance R1, R2, R3 and increase the phase-to-phase current i2, i6 , If i10 is small, the current added at the P point of each phase becomes small (ie, the absolute value of the current to be divided is reduced).

(2) In the current distribution (i4, i8, i12, i13, i14a, 14b, 14c) of the combined current at point P of each phase, the magnitude of the leakage current i14a, 14b, 14c can be reduced by appropriately adjusting the magnitude of the ground resistance R6. there is.

On the other hand, in the second prior art mentioned in the background art of the invention,

(1) Since the insulation tube is not interposed, the resistance R1 is very small, so the current i2 becomes very large, and the absolute value of the combined current becomes very large.

(2) Since no resistance between the three-phase line R and the neutral line N was found or not mentioned, most of the combined current flows into the neutral line N, which is a serious error.

(3) Even when the leakage currents i14a, 14b, and 14c flow, if the battery current i13 and the leakage currents i14a, 14b, and 14c are distributed only, the leakage currents i14a, 14b, and 14c can be suppressed as much as possible. In case of an accident where the neutral wire is disconnected, there is no path through which the current of i4 flows, and all the current flows to i14a, 14b, and 14c, resulting in a major accident.

6 is a view for explaining experimental conditions for testing the effect of preventing electric shock to a human body when a submerged electrical facility in which a three-phase, four-wire phase-to-phase current and leakage current limiting device is installed according to the present invention is flooded, and FIG. It is a drawing for explaining the human body contact in case of flooding of the electric equipment in which the three-phase four-wire phase current and leakage current limiting device of the flooded electric equipment according to the present invention is installed.

Arrangement of three-phase lines R, S, T and neutral line N of the three-phase four-wire phase current and leakage current limiting device 100 of the flooded electrical equipment according to the present invention using the experimental design as shown in FIG. Measure the magnitude of leakage current according to the size and interval.

As shown in FIG. 6, electrical insulation tubes (insulation tubes 24a, 24b, 24c) are placed around the phase line portions 22a, 22b, and 22c, and the neutral wire tubes (tubular lines 26a, 26b, 26c)). An enclosure tube (housing ground (28a, 28b, 28c)) is placed outside the neutral tube.

The three-phase lines R, T, and S are connected to the three-phase line parts 22a, 22b, and 22c, the neutral line N is connected to the neutral line tube (tubular line lines 26a, 26b, and 26c), and the ground line G is the enclosure tube ( It is designed as an electrical terminal structure connected to the housing ground (28a, 28b, 28c). The electric load 130 is 6W.

When the three-phase line portions 22a, 22b, and 22c and the neutral tubes (tubular lines 26a, 26b, and 26c) are submerged, insulation is destroyed, resulting in ground leakage current and sheath leakage current. At this time, the ground leakage current is suppressed (less than 15 mA) to prevent the circuit breaker from going down so that the electric device operates normally even when submerged. In addition, leakage current is suppressed (less than 10mA) to prevent electric shock accidents.

To measure the leakage current, as shown in FIG. 7, it has a human body contact surface 110, and an alternative resistance 120 that can replace the resistance of the human body is set to 1 kΩ (common standard for electrical and mechanical safety) . At this time, the human body contact surface 110 was made of a copper plate with a width of 200 mm and a length of 100 mm.

).The surface area S of the three-phase line portions 22a, 22b, and 22c is changed, and the electrical insulation pipe (insulation pipe ( 24a, 24b, 24c)) while changing the length ℓ, change the resistance R between the phase line parts 22a, 22b, 22c and the neutral tube (tubular line 26a, 26b, 26c) (

).

The current flowing through the neutral wire was measured using the ammeter A1, the ground current was measured using the ammeter A2, and the leakage current was measured using the ammeter A3, which is summarized in Table 1 below. Here, the phase-to-phase current is the value obtained by subtracting the load current from the value of the ammeter (A1+A2+A3).

In Table 1, L is the height of the copper pipe adopted as the neutral pipe (tubular line (26a, 26b, 26c)), d is the neutral pipe (tubular line (26a, 26b, 26c)) and the phase line portion (22a, 22b, 22c) Interval, I, represents the length of the phase line portions 22a, 22b, and 22c. The diameters of the phase line portions 22a, 22b, and 22c were equally set to 6 mm.

In addition, it can be confirmed that when the neutral wire is disconnected due to an accident, most of the current flows as a ground leakage current, and the enclosure leakage current is limited to a safe range. These experimental results are summarized in Table 2 below.

Referring to the experimental data according to Tables 1 and 2, when the 3-phase 4-wire phase current and leakage current limiting device 100 of the flooded electrical installation structure as shown in FIG. 6 is flooded, the current flows from the live wire to the enclosure tube. (housing ground (28a, 28b, 28c)) it can be seen that most of them are directed toward the neutral wire without diverging.

In addition, it can be confirmed that the magnitude of the earth leakage current can be limited by changing the electrical resistance between the live wire (three-phase line) and the neutral wire.

Most of the current generated by insulation breakdown due to flooding is induced to the neutral wire and the ground wire, and the enclosure leakage current is very limited. In the event of a complex accident such as flooding of the three-phase four-wire phase current and leakage current limiting device 100 of the flooded electrical equipment according to the present invention and disconnection of the neutral wire, current flows through the ground wire G and the enclosure leakage current is within a safe current range. there will be

Through these experimental results, L is the height of the copper pipe adopted as the neutral pipe (tubular line (26a, 26b, 26c)), d is the neutral pipe (tubular line (26a, 26b, 26c)) and phase line parts (22a, 22b, 22c) Interval, I is the length of the phase line parts (22a, 22b, 22c), regardless of the specifications of each component constituting the 3-phase 4-wire phase current and leakage current limiting device 100 of the submerged electrical equipment It can be seen that electric shock protection is possible.

As described above, the present invention is a three-phase four-wire phase current and leakage current limiting device of a submerged electrical facility having a simple structure and easy installation to detect phase current and leakage current between three-phase lines during flooding of electrical facilities. Since it can be limited, it is possible to reduce the current flowing to the human body in contact with the short circuited electricity, thereby effectively preventing an electric shock accident.

In addition, according to the present invention, the length of the passage between the inner three-phase line and the inner neutral is increased by adjusting the length of the insulation tube inserted between the inner three-phase line and the inner neutral, or the area of the three-phase line is adjusted to increase the length of the three-phase line. The current between the three phases can be limited by increasing the resistance between the negative and the tubular line.

Various embodiments disclosed in this specification and drawings are only presented as specific examples to aid understanding, and are not intended to limit the scope of various embodiments of the present invention.

Therefore, the scope of various embodiments of the present invention includes all changes or modified forms derived based on the technical spirit of various embodiments of the present invention other than the embodiments described herein are included in the scope of various embodiments of the present invention. should be interpreted as being

The present invention can be used industrially in the field of phase-to-phase current and leakage current limiting technology and its applied technology.

2a, 2b, 2c: 3-phase line
4: Neutral wire
6: ground wire
100: 3-phase 4-wire phase current and leakage current limiting device for submerged electrical equipment
12a, 12b, 12c: 3-phase line terminal
14a, 14b, 14c: neutral wire terminal
16a, 16b, 16c: ground wire terminal
20a, 20b, 20c: terminal connection check circuit
22a, 22b, 22c: phase line part
24a, 24b, 24c: insulation tube
26a, 26b, 26c: Tubular line
28a, 28b, 28c: housing ground
32a, 32b, 32c: internal phase line
34a, 34b, 34c: internal neutral wire
36a, 36b, 36c: internal ground wire
200: electrical equipment

Claims (5)

3-phase, 4-wire phase-to-phase current and leakage current limiting of submerged electrical facilities that is connected to the distribution lines of electrical facilities and electrically connected to the electrical facilities to prevent electric shock in the event of flooding of the electrical facilities or other electrical facilities located nearby. In the device,
One end portion has three-phase line terminals 12a, 12b, and 12c electrically connected to the three-phase lines 2a, 2b, and 2c of the distribution line, and the other end portion is electrically connected to the electrical equipment 200, respectively. internal phase lines 32a, 32b, and 32c having phase line portions 22a, 22b, and 22c that are not surrounded by an insulator;
One end has neutral wire terminals 14a, 14b, 14c electrically connected to the neutral wire 4 of the distribution line, and the other end is electrically connected to the electrical equipment 200 and the phase line parts 22a, 22b, 22c ) And internal neutral wires (34a, 34b, 34c) electrically connected to the tubular lines (26a, 26b, 26c) of a conductive material surrounding the conductor, respectively;
One end portion has ground wire terminals 16a, 16b, and 16c electrically connected to the ground wire 6 of the distribution line, and the other end portion is electrically connected to the electrical equipment 200, formed of an insulator, and a tubular line 26a , 26b, 26c) and internal ground wires (36a, 36b, 36c) electrically connected to housing grounds (28a, 28b, 28c) provided with ground wires on the inner circumferential surface of the housing, respectively;
Insulation tubes 24a, 24b, 24c disposed between the inner phase lines 32a, 32b, 32c and the tubular lines 26a, 26b, 26c and surrounding the inner phase lines 32a, 32b, 32c, respectively;
3-phase 4-wire phase current and leakage current limiting device for flooded electrical equipment including According to claim 1,
The tubular lines 26a, 26b, and 26c extend in both directions from both ends of the phase line portions 22a, 22b, and 22c, and the insulated tubes 24a, 24b, and 24c extend along the phase line portions 22a, 22b, and 22c, and It extends in both directions from both ends of the tubular lines 26a, 26b, and 26c, and the housing grounds 28a, 28b, and 28c extend in both directions from both ends of the tubular lines 26a, 26b, and 26c. 3-phase 4-wire phase current and leakage current limiting device. According to claim 1,
It is electrically connected between the neutral wire terminals 14a, 14b, 14c and the ground wire terminals 16a, 16b, 16c, and further includes a terminal connection check circuit 20a, 20b, 20c in which a resistor and an LED are connected in series. 3-phase 4-wire phase current and leakage current limiting device for electrical equipment. According to claim 1,
The length of the passage between the internal phase lines 32a, 32b and 32c and the internal neutral wires 34a, 34b and 34c is increased by adjusting the length of the insulation tubes 24a, 24b and 24c, or the phase line units 22a, 22b, 22c) to increase the resistance between the phase line parts 22a, 22b, and 22c and the tubular lines 26a, 26b, and 26c by adjusting the area of 22c) to limit the phase-to-phase current. current limiter. According to claim 4,
The current flowing through the tubular lines 26a, 26b, and 26c by adding the limited phase-to-phase current and the on-current from the electric load to the internal neutral wires 34a, 34b, and 34c causes the internal ground wire 36a through the housing grounds 28a, 28b, and 28c. , 36b, 36c) to the ground, so that the leakage current is limited by a 3-phase, 4-wire phase current and leakage current limiting device for submerged electrical equipment.

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