KR20160112779A - Anti-Electric Shock Apparatus In Water Immersion and Method Thereof - Google Patents

Abstract

The present invention relates to an electric shock prevention device in case of flooding and a method thereof and provides an electric shock prevention device in case of flooding for preventing generation of a leakage current by compensating the difference of contact resistance due to the difference of surface areas of exposed terminals of an electric device when using a neutral grounding method in a single-phase, two-wire, and low-voltage power distribution system and a method thereof. To that end, according to an embodiment of the present invention, the electric shock prevention device in case of flooding includes: a transformer which supplies a voltage using a neutral grounding method in a single-phase, two-wire, and low-voltage power distribution system; an earth leakage breaker which is connected to the power outputted by the transformer; a current measurement unit which measures the amount of current passing through the earth leakage breaker; a control unit which calculates the contact resistance to be compensated using the amount of current from the current measurement unit and transmits a corresponding control signal; and a contact resistance compensation unit which compensates the contact resistance according to the control signal from the control unit.

Description

TECHNICAL FIELD [0001] The present invention relates to an anti-electric shock device,

Some embodiments of the present invention relate to an apparatus and method for preventing electric shock in flooding, and more particularly to a method and apparatus for preventing electric shock in flooding, and more particularly, to a method of preventing electric shock in flooding using a neutral point grounding system in a single- The present invention relates to an apparatus for preventing an electric shock during immersion and a method for preventing leakage current by compensating for a difference.

In some embodiments of the present invention, the electrical device includes all electrical equipment such as a streetlight, a motor, a high-voltage transformer, a traffic light controller, an agricultural machine, and the like.

Generally, there are various low-voltage distribution systems (hereinafter, referred to as "first prior arts") such as a single-phase two-wire low-voltage distribution system, a single-phase three-wire system low-voltage distribution system, and a three-

1, a conventional single-phase, two-wire type low-voltage power distribution system will be described. In FIG. 1, And minus (-) terminals, and the grounding method is used in which the negative terminal is connected to the ground side.

Next, considering the single-phase three-wire low-voltage distribution system, most of the electric apparatuses used 110V in some cases. Then, as the industrialization became active, the time came to change to 220V. As a result, a low-voltage power distribution system that can use both the 110V electrical apparatus already used and the newly-generated 220V electrical apparatus becomes necessary. The low-voltage power distribution system at this time is a single-phase three-wire low-voltage power distribution system.

Next, considering the three-phase, four-wire low-voltage distribution system, the demand for three-phase electricity suitable for power use has increased as the industrialization has been activated. Accordingly, the three- The distribution system has also been increased in proportion to it and is now being used in most low-voltage distribution systems.

The R, S, and T terminals shown in FIG. 2 are connected to a 380 V three-phase motor or the like, and are connected to an N terminal and R, S, and T And 220V electric power is taken out by using a combination of any one of the terminals.

In general, when using electricity, the single-phase, two-wire low-voltage distribution system, the single-phase three-wire low-voltage distribution system and the 220V electricity drawn from the three-phase four-wire low-voltage distribution system are all the same. However, This is a lot different. Hereinafter, the single-phase three-wire low-voltage distribution system and the three-phase four-wire low-voltage distribution system will be described with reference to FIG.

3 is a view showing an outlet in a conventional single-phase three-wire low voltage distribution system and a three-phase four-wire type low-voltage distribution system.

First, in the case of a three-phase, four-wire low-voltage distribution system, 220V is measured when the voltage of the first terminal and the third terminal of the ground is measured, and 0V is measured when the voltages of the second terminal and the third terminal are measured.

In the case of a single-phase three-wire low-voltage distribution system, 110V is measured when the voltage of the first terminal and the third terminal of the ground is measured, and 110V is also measured when the voltages of the second terminal and the third terminal are measured.

It can be seen that the earth (ground) voltages of the single phase three-wire low-voltage distribution system and the three-phase four-wire low-voltage distribution system are different from each other.

FIG. 4A is a graph showing a result of measurement of leakage voltage during flooding in a conventional single-phase, two-wire low-voltage distribution system, and FIG. 4B is a graph showing a result of measurement of leakage current during immersion in a conventional single- FIG. 4C is an equivalent circuit diagram of FIG. 4B, and FIG. 4D is a diagram showing an instantaneous current flow in the equivalent circuit diagram of FIG. 4C.

As shown in FIG. 4A, two lines of positive and negative terminals are extended from a 220V power source drawn from a conventional single-phase, two-wire low-voltage power distribution system and immersed in a plastic water tank, and a distance of about 1m from the plus and minus lines in water , The voltage measured between the water and the ground terminal is measured by a voltmeter. In this case, the measured voltage is 110V, which is a middle value of 220V. Therefore, when a person touches the water and the ground terminal at the same time by hand, a lot of electric current flows in an instant, and the electric shock immediately occurs. At this time, the amount of leakage current can be measured by connecting an ammeter between water and a ground terminal as shown in FIG. 4B.

Assuming that the ground resistance between the two grounds in FIG. 4B is about 3 k ?, the equivalent circuit of FIG. 4B can be represented as FIG. 4C.

Referring to FIG. 4D, in the instantaneous current flow in the equivalent circuit, current flows along the path a and path b according to the electromotive force direction by the 220V voltage, and then flows along the path c through the water. That is, since the forces do not cancel each other in the current flow, the ammeter shows a large current value. Therefore, when a person is positioned at the position of the ammeter (that is, when a person touches the water and the ground terminal directly by hand), a large amount of current flows instantaneously, leading to an electric shock.

The conventional single-phase, two-wire low-voltage power distribution system and the three-phase, four-wire low-voltage power distribution system have a disadvantage in that when the electric circuit breaker is normally operated, the operation of the electric device is stopped. Assuming that the earth leakage circuit breaker does not operate during flooding, a large amount of current is leaked to the outside and there is a great risk of electric shock accident.

Korean Patent Laid-Open Publication No. 10-2005-0037986 (hereinafter referred to as " second prior art ") discloses a technique in which an electric device is flooded during energization and a leakage current flowing from a charger To prevent a short circuit or an electric shock accident. The second prior art immersion electric shock protection device is exemplified by several embodiments. The common point of the embodiments is that the connection terminal block in which the exposed connection terminals (single-phase connection terminal P, neutral terminal N, ground terminal E) A flat plate-like metal plate having a large area covering all of other devices such as a breaker and a ballast is electrically connected to the neutral point terminal N or the ground terminal E under the bottom surface of the connecting terminal block, And the like.

According to the second conventional art, even when the exposed connection terminals of the connection terminal block are submerged, almost all of the current flowing through the charging section flows through the flat plate-like metal plate, So that an electric shock or a short circuit accident can be prevented.

However, according to the experiment of fabricating the immersion electric shock preventing device having the same configuration as that of the second conventional art, the second conventional technique has some fatal weak points.

First, in order to obtain a short circuit and an electric shock prevention effect, a metal plate for preventing an electric leakage must be connected to the neutral point terminal of the AC power source, and it is a problem to ensure this. According to the description of the second prior art, a flat metal plate should be connected to the neutral point terminal (N) or the ground terminal (E) of the AC power source in order to obtain an effect of preventing leakage during immersion. One way to do this is to locate the first supply line connected to the neutral point terminal on the power side of the two strands with a single-phase (1P) AC power supply line in advance and connect it directly to the connection terminal to which the plate- And the second supply line is directly connected to the remaining connection terminal. However, this method has a problem in that it is troublesome to find the first supply line connected to the neutral point terminal on the power source side. If it is mistakenly connected, desired leakage and electric shock prevention effect can not be obtained. There is a problem that the load is always connected to the power source side, thereby wasting power. To ensure that the load is connected to the power supply only when necessary, consider placing a plug and receptacle between the power supply and the connection terminal. In such a case, the path through which the plate-shaped metal plate is electrically connected to the AC power source is connected through the terminal -> plug terminal -> outlet of the connection terminal block. At this time, in order for the plate-type metal plate to be connected to the neutral point terminal of the AC power source, the plug terminal connected to the first connection terminal J1 of the connection terminal block to which the flat metal plate is connected is connected to the outlet terminal connected to the neutral point terminal Be guaranteed. The plug has two plug terminals (IN1, IN2) and one ground terminal (G) which are respectively electrically connected to three terminals of the connection terminal block. Incidentally, the two plug terminals IN1 and IN2 have the same appearance. In addition, the two receptacle terminals of the receptacle to which the AC power is applied, that is, the first receptacle terminal N connected to the neutral point terminal of the AC power source and the second receptacle terminal R connected to the single- Therefore, in order for the first plug terminal IN1 to be connected to the first receptacle terminal N when the user plugs the plug into the outlet, it is necessary to know which one of the two plug terminals is the first plug terminal IN1, It is also necessary to know which of the two receptacle terminals is the first receptacle terminal N. It is actually very difficult to guarantee these conditions. Even users who know the terminal polarity of the plug and receptacle may fail to connect with the correct polarity if they are not careful when plugging the plug into the outlet. One way to prevent the user from making a mistake is to have a polarity mark on the plug terminal and the outlet terminal. However, there is a possibility that a user who does not know this might plug the plug into the outlet and consider the possibility of causing mistakes due to carelessness. At the same time, this method also has the disadvantage of being incomplete.

According to the experiment, the metal plate for preventing electric leakage is connected to the ground terminal (N) instead of the neutral point terminal (N). However, according to the second prior art, the same effect can be obtained when the metal plate for preventing electric leakage is connected to the ground terminal E), there is a disadvantage that a desired leakage current and an electric shock prevention effect can not be obtained.

Second, the electro-leakage conductive metal plate proposed by the second prior art does not provide a leakage preventing function and an electric shock prevention function in the case of immersion, as claimed in the second prior art. Various tests have confirmed that the cause of the leakage current is the 'flat plate' structure of the conductive metal plate. According to the experiment, as shown in the second prior art, in the structure in which a large plate-shaped metal plate is disposed below the connection terminal block or the like, the leakage current increases in a few seconds to several tens of seconds after the connection terminal block is flooded, The electric power supply to the terminal board was cut off and the hand terminal was immersed in the water, an electric shock was felt. The reason for this is that the distance between the conductive metal plate for preventing electric leakage and the second connection terminal connected to the single-phase voltage terminal is excessively long and the body of the connection terminal block made of the insulating material is disposed therebetween and obstructs current flow through the shortest path therebetween Therefore, it is presumed that the resistance value between them is large, so that a part of the amount of current from the second connection terminal flows into the electro-leakage prevention conductive metal plate, but a substantial amount of current leaks to another place. In the second conventional technique, the size of the plate-shaped conductive plate for preventing electric leakage is 50 × 30 cm when the operating voltage is 380 V. However, when a conductor plate having a much larger size (for example, 60 × 60 cm) is used, There is a change that takes a longer time to fall, but eventually the earth leakage breaker tripped. Therefore, it was found that the size of the conductive plate is not a problem to be solved by increasing the size of the conductive plate. Actually, the size of the conductive plate can not be increased indefinitely because of the space limitation that the conductive plate can be installed. Therefore, this method can not be fundamentally solved by increasing the size of the plate-shaped conductor plate.

As described above, according to the first prior art, when the electric leakage is flooded, the operation of the electric device is stopped when the electric leakage breaker is normally operated, and when the electric device is flooded, There is a problem in that the risk of an electric shock accident is very great, and the second prior art has a problem in that it can not provide an electric leakage and an electric shock prevention effect. In order to solve such a problem, the third prior art described below (see Figs. 5 to 7) has been developed by the present inventors.

FIG. 5 is a view for explaining a conventional neutral point grounding type transformer and its method, and shows a neutral point grounding method in a single-phase, two-wire low-voltage power distribution system.

As shown in Fig. 5, the third prior art includes a transformer 50 that supplies voltage using a neutral point grounding scheme in a single-phase, two-wire low-voltage power distribution scheme. That is, in the third prior art, the neutral point (51, the middle position of the secondary winding) of the secondary winding (output side winding) is set to be And a neutral point grounding method is used to connect the ground 52 to the ground. Other transformer technologies are well known in the art and will not be described in detail here.

As shown in FIG. 5, when the neutral point grounding system in the single-phase, two-wire low-voltage power distribution system is used, when the exposed terminals of the electric device are submerged, a current flows between the cathode terminals, that is, -) electrode terminal and their forces cancel each other, so that almost no leakage current occurs between the positive terminal and the outside except for the periphery thereof (see FIGS. 6A to 6D described later).

FIG. 6A is a graph showing a result of measurement of a leakage voltage at the time of immersion when a neutral point grounding system is used in a conventional single-phase, two-wire low-voltage power distribution system. FIG. FIG. 6C is an equivalent circuit diagram of FIG. 6B, and FIG. 6D is a diagram showing an instantaneous current flow in the equivalent circuit diagram of FIG. 6C.

As shown in FIG. 6A, the two lines of the positive and negative terminals are extended from the 220V power source drawn from the neutral point grounding system in the single-phase, two-wire low-voltage power distribution system and immersed in the plastic water tank. When the voltage between the water and the ground terminal is measured by a voltmeter at a distance, the measured voltage is less than 10V. More specifically, for example, a voltage of about 4 V to 10 V is measured. Therefore, in general, it is known that electric shock does not occur at a voltage of less than 30 V. Therefore, even if the hand and the ground terminal are in contact with each other at the same time, electric current hardly flows. As described above, it can be confirmed that the current hardly flows by connecting the ammeter between the water and the ground terminal as shown in FIG. 6B and measuring the leaked current.

Assuming that the ground resistance between the two grounds of FIG. 6B is about 3 k ?, the equivalent circuit of FIG. 6B can be represented as FIG. 6C.

Referring to FIG. 6D, referring to the instantaneous current flow in the equivalent circuit, a current due to the 220V voltage flows along the g path by the direction of the electromotive force by the 220V voltage (for example, from upper to lower direction in FIG. 6D) After flowing, it flows through the water along the i path. More specifically, the voltage between the terminal d and the terminal e is 220V. As described above, since the first closed circuit (g-path of the water-i-path of the water) having a potential difference of 220 V between the terminal d and the terminal e and the water in the plastic tank is formed, a current of 220 V is naturally flown along the first closed circuit do.

On the other hand, the voltage between the d terminal and the f terminal and between the f terminal and the e terminal is 110V, respectively. In this way, a second closed circuit (g path-water path-h path) and a third closed circuit (h path-water path), each having a potential difference of 110 V between the terminal d and f and between the terminal f and e, The current between the d terminal and the f terminal and the voltage between the f terminal and the e terminal are equal to each other at 110 V and the electromotive force direction Are opposite to each other and the current flows therebetween are opposite to each other, so that the current hardly flows. That is, the upper 110V voltage and the lower 110V voltage are equal to each other with respect to the neutral point (51), and the directions of the electromotive force due to the two voltages are opposite to each other in the position of the ammeter, So that there is almost no potential difference and almost no current flows, so that the value of the ammeter becomes almost "0".

As a result, if the single-phase 220V of the neutral point grounding type in the single-phase, two-wire low-voltage distribution system is used for the electric equipment which is likely to be flooded, the earth leakage breaker may not operate due to failure or the primary side of the earth leakage breaker may flood The risk of electric shock can be greatly reduced. In other words, by using the neutral point grounding method in the single-phase, two-wire low-voltage power distribution system, when the exposed terminals of the electric device are flooded, leakage current leaking out from the terminals hardly occurs, and electric shock can be fundamentally prevented .

7 is a view for explaining a conventional method of preventing a circuit breaker of a circuit breaker, in which the circuit breaker 720 is integrated with the circuit breaker 710.

In general, the earth leakage breaker 710 is a wiring mechanism that automatically detects a state in which a voltage higher than the rated voltage is input, or a state in which an electric leakage occurs in the electric device, and automatically cuts off electricity. In this case, the earth leakage breaker (710) shall perform the earth leakage shutoff operation within 0.03 seconds after occurrence of the earth leakage and the earth leakage shutoff operation within 0.1 seconds after the occurrence of the earth leakage in the case of the industry standard. Since the earth leakage breaker 710 is a known technology, it will not be described in detail here. The earth leakage breaker 710 has a function of supporting a positive exposure terminal 721 connected to a plus terminal and a minus exposure terminal 722 connected to a minus terminal connected to a power output from the transformer 50 described above with reference to Fig. . The earth leakage breaker 710 is preferably a waterproof type earth leakage breaker.

At this time, a short circuit may occur in a normal state, not immersion, and in a case where an electric device is submerged. If a short circuit occurs, the electric leakage circuit breaker 710 normally operates to interrupt the electric supply, thereby stopping the operation of the electric device at the rear end.

By the way, as described above with reference to Figs. 5 and 6A to 6D, by using the neutral point grounding method in the single-phase two-wire low-voltage power distribution system, when the exposed terminals of the electric device are flooded, If the electric leakage can be prevented by greatly reducing the leakage current, it is possible to prevent the circuit breaker operation of the leakage circuit breaker when the leakage current occurs due to flooding, To be able to operate normally.

Therefore, the third prior art is to prevent the interruption of the earth leakage breaker 710 by allowing the exposed positive and negative terminals of the electric device to flood within a predetermined time difference (e.g., within 0.03 seconds) And a blocking operation preventing unit 720.

At this time, the blocking operation preventing unit 720 connects the positive exposure terminal 721 connected to the plus terminal of the earth leakage breaker 710 and the minus exposure terminal 722 connected to the minus terminal of the earth leakage breaker 710 to a predetermined distance The negative exposure terminal 721 and the negative exposure terminal 722 are immersed within a predetermined time difference so that the positive exposure terminal 721 and the negative exposure terminal 722 are floated within a predetermined time difference, (722), thereby preventing the earth leakage breaker (710) from interrupting operation. In other words, the blocking operation preventing unit 720 may be formed so that the lower end of the positive exposure terminal 721 and the lower end of the negative exposure terminal 722 form a balanced state (the lower end is balanced using a water level system or the like at the time of installation) So that current can flow from the positive exposure terminal 721 to the negative exposure terminal 722 so that the leakage circuit breaker 710 can not detect the leakage current due to flooding and the blocking operation can be prevented from occurring .

The blocking operation prevention unit 720 further includes a support member 723 for supporting the positive exposure terminal 721 and the negative exposure terminal 722 to maintain the separation distance and the bottom balance. The blocking operation preventing portion 720 further includes a protection case 724 for protecting the blocking operation preventing portion 720 from the flow rate of water. At this time, the protective case 724 further includes a foreign matter inflow prevention part 725 for allowing water to be received and discharged and preventing foreign matter from entering. And the protective case 724 further includes an air exhaust portion 726 for exhausting the air inside when water is received.

As described above, according to the third prior art, when the neutral point grounding system is used in the single-phase, two-wire low-voltage power distribution system, leakage current does not occur even if the exposed terminals are submerged.

However, in the third conventional art, the exposed terminals are left-right type in most cases, and the exposed surface area is almost the same, so that the contact resistance (the resistance when the exposed surface area is in contact with water in the flooded state) is also substantially the same. Leakage currents do not occur at the time of flooding, but when the exposed surface areas of the exposed terminals are different from each other and the contact resistances are different from each other, there is a problem that leakage currents corresponding to the difference in contact resistance are generated. SUMMARY OF THE INVENTION

Therefore, one embodiment of the present invention is to prevent the occurrence of leakage current by compensating the difference in contact resistance due to the difference in the surface area of the exposed terminals of the electric device while using the neutral point grounding method in the single- Device and method therefor.

The objects of the present invention are not limited to the above-mentioned objects, and other objects and advantages of the present invention which are not mentioned can be understood by the following description, and will be more clearly understood by the embodiments of the present invention. It will also be readily apparent that the objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

According to another embodiment of the present invention, there is provided an apparatus for preventing electric shock in a flooded state, comprising: a transformer for supplying a voltage using a neutral point grounding system in a single-phase, two-wire low-voltage distribution system; An earth leakage breaker connected to a power source output from the transformer; A current measuring unit for measuring an amount of current passing through the earth leakage breaker; A controller for calculating a contact resistance to be compensated by using the amount of current from the current measuring unit and sending out a corresponding control signal; And a contact resistance compensator for compensating the contact resistance according to a control signal from the controller.

Meanwhile, a method according to an embodiment of the present invention includes the steps of: receiving a voltage from a transformer using a neutral point grounding method in a single-phase, two-wire low-voltage power distribution system; Measuring an amount of current passing through the earth leakage breaker by the current measuring unit; Calculating a contact resistance to be compensated by using a current amount from the current measuring unit and transmitting a corresponding control signal; And the contact resistance compensating unit compensating the contact resistance according to the control signal from the control unit.

According to the embodiment of the present invention, it is possible to prevent the leakage current from occurring by compensating for the difference in the contact resistance due to the difference in the surface area of the exposed terminals of the electric device while using the neutral point grounding method in the single- There is an effect that the electric shock can be fundamentally prevented.

1 is a view for explaining a conventional single-phase, two-wire low voltage distribution system,
2 is a view for explaining a conventional three-phase four-wire type low voltage distribution system,
3 is a view showing an outlet in a conventional single-phase three-wire low-voltage distribution system and a three-phase four-wire type low-voltage distribution system,
FIG. 4A is a view showing a result of measurement of leakage voltage at the time of immersion in a conventional single-phase, two-wire low-
FIG. 4B is a view showing a state in which leakage current during flooding is measured using an ammeter in the conventional single-phase, two-wire low voltage distribution system,
FIG. 4C is an equivalent circuit diagram of FIG. 4B,
4D is a diagram showing the instantaneous current flow in the equivalent circuit diagram of FIG. 4C,
5 is a view for explaining a conventional neutral point grounded transformer and a method thereof,
FIG. 6A is a graph showing a result of measurement of a leakage voltage at the time of immersion when a neutral point grounding system is used in a conventional single-phase, two-wire low-
FIG. 6B is a diagram showing a state in which leakage current during flooding is measured using an ammeter when a neutral point grounding system is used in a conventional single-phase, two-wire low voltage distribution system;
Fig. 6C is an equivalent circuit diagram of Fig. 6B,
FIG. 6D is a diagram showing the instantaneous current flow in the equivalent circuit diagram of FIG. 6C,
FIG. 7 is a view for explaining a conventional method of preventing a circuit breaker of a circuit breaker,
FIG. 8 is a view for explaining an electric shock preventive apparatus for flooding according to an embodiment of the present invention;
9 is a flowchart illustrating a method of preventing an electric shock during flooding according to an embodiment of the present invention.

In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings in order to facilitate a person skilled in the art to easily carry out the technical idea of the present invention. .

And throughout the specification, when a part is referred to as being "connected" to another part, it includes not only "directly connected" but also "electrically connected" with another part in between. Also, when a component is referred to as " comprising "or" comprising ", it does not exclude other components unless specifically stated to the contrary . In addition, in the description of the entire specification, it should be understood that the description of some elements in a singular form does not limit the present invention, and that a plurality of the constituent elements may be formed.

8 is a view for explaining an electric shock preventive apparatus in a flooded state according to an embodiment of the present invention.

As shown in FIG. 8, the flooded-electric-shock-preventing apparatus according to an embodiment of the present invention can use the neutral point grounding method in the single-phase, two-wire low-voltage power distribution system, Thereby compensating for the difference in contact resistance due to the difference.

That is, in the flooded-electric-shock-preventing apparatus according to an embodiment of the present invention, when there is a possibility of leakage current due to a difference in surface area between the two exposed terminals 721 and 722, , The leakage current is sensed by using the current measurement value of the current measurement unit 810 and the difference of the contact resistance due to the surface area difference of the exposure terminals 721 and 722 is compensated through the contact resistance compensation unit 830 By making the contact resistances of the exposed terminals 721 and 722 have substantially the same value, it is possible to prevent the occurrence of a leakage current, thereby preventing electric shock fundamentally.

To this end, an apparatus for preventing electric shock in a flooded state according to an embodiment of the present invention includes a transformer 50 for supplying a voltage using a neutral point grounding method in a single-phase, two-wire low-voltage power distribution system, The current measuring unit 810 for measuring the amount of current passing through the connected leakage current circuit breaker 710, the earth leakage breaker 710, the contact resistance to be compensated by using the amount of current from the current measuring unit 810, And a contact resistance compensating unit 830 for compensating the contact resistance according to a control signal from the controller 820. [

At this time, in the transformer 50, the neutral point (51, the middle position of the secondary winding) of the secondary winding (output side winding) is set at And a neutral point grounding method is used to connect the ground 52 to the ground.

The earth leakage breaker 710 is a wiring mechanism that automatically detects a state in which a voltage higher than the rated voltage is inputted or a state in which an electric leakage occurs in the electric device, and thereby cuts off electricity automatically.

The current measuring unit 810 measures the amount of two currents passing through the earth leakage breaker 820 (the amount of each current flowing through the positive and negative wires) and transmits them to the controller 820. Alternatively, the current measuring unit 810 may calculate the difference between the measured two current amounts and transmit the difference to the controller 820. 8, the current measuring unit 810 may be implemented using two ammeters connected in a one-to-one manner to the positive and negative wires. The current measuring unit 810 may be provided at a rear end of the earth leakage breaker 710, (That is, between the transformer 50 and the earth leakage breaker 710), or may be provided inside the earth leakage breaker 710 or the like.

The control unit 820 calculates the contact resistance to be compensated in the contact resistance compensating unit 830 by using the amount of current from the current measuring unit 810 and outputs a control signal corresponding to the calculated contact resistance to the contact resistance compensating unit 830. [ (830). At this time, the control unit 820 receives the two current amounts from the current measuring unit 810 and calculates the difference value, and then calculates the contact resistance to be compensated in the contact resistance compensating unit 830, A contact resistance to be compensated in the contact resistance compensating section 830 is calculated by receiving the difference value between the two current amounts from the contact resistance compensating section 810. Here, the control signal is a signal for compensating the contact resistance of the exposed terminals 721 and 722 on the side having a large contact resistance. 8, the control unit 820 may be provided inside the transformer 50 or may be provided inside the earth leakage breaker 710, preferably inside the current measuring unit 810, And the like.

The contact resistance compensating unit 830 compensates the contact resistance of the exposed terminals 721 and 722 on the side having a large contact resistance according to the control signal from the controller 820. At this time, the contact resistance compensating unit 830 changes the resistance value according to the control signal from the control unit 820 to change the contact resistance to the contact resistance adjusters 831 and 833 and the contact resistance adjusters 831 and 833 And contact resistance compensation terminals 832 and 834 connected to compensate for contact resistance (exposure area). The contact resistance controllers 831 and 833 may be realized as variable resistors and the contact resistance compensation terminals 832 and 834 are preferably provided at the lower ends of the exposure terminals 721 and 722 to be prepared for immersion Do.

FIG. 9 is a flowchart illustrating a method of preventing an electric shock during flooding according to an embodiment of the present invention, and a specific embodiment thereof has been described in detail with reference to FIG. 8, Brief description will be given.

First, the earth leakage breaker 710 is supplied with a voltage from the transformer 50 using the neutral point grounding method in the single-phase, two-wire low voltage distribution system (910).

The current measuring unit 810 measures the amount of current passing through the earth leakage breaker 710 (920).

Then, the control unit 820 calculates a contact resistance to be compensated by using the amount of current from the current measuring unit 810, and transmits a corresponding control signal (930).

The contact resistance compensating unit 830 compensates the contact resistance according to the control signal from the controller 820 (940).

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, Various permutations, modifications and variations are possible without departing from the spirit of the invention. Therefore, the scope of the present invention should not be construed as being limited to the embodiments described, but should be determined by the scope of the appended claims, as well as the appended claims.

50: Transformer 710: Earth leakage breaker
810: current measuring unit 820:
830: Contact resistance compensator

Claims (3)

An apparatus for preventing electric shock during flooding,
A transformer for supplying a voltage using a neutral point grounding method in a single phase two-wire low voltage distribution system;
An earth leakage breaker connected to a power source output from the transformer;
A current measuring unit for measuring an amount of current passing through the earth leakage breaker;
A controller for calculating a contact resistance to be compensated by using the amount of current from the current measuring unit and sending out a corresponding control signal; And
A contact resistance compensating unit for compensating for a contact resistance according to a control signal from the controller,
Wherein the electrolytic waterproofing device comprises:
The method according to claim 1,
Wherein the contact resistance compensating section comprises:
A contact resistance regulator for regulating a contact resistance by changing a resistance value according to a control signal from the control unit; And
A contact resistance compensation terminal connected to the contact resistance regulator for compensating for contact resistance;
Wherein the electrolytic waterproofing device comprises:
A method of preventing electric shock in flooding,
A step of receiving a voltage from an earth leakage breaker of a "transformer using a neutral point grounding method in a single-phase two-wire low-voltage power distribution system ";
Measuring an amount of current passing through the earth leakage breaker by the current measuring unit;
Calculating a contact resistance to be compensated by using a current amount from the current measuring unit and transmitting a corresponding control signal; And
Wherein the contact resistance compensation unit compensates the contact resistance according to a control signal from the control unit
Wherein the waterproofing method comprises the steps of:

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