KR100458181B1 - Direct current breaker breakable a low current and method of breaking the same - Google Patents

Abstract

The present invention relates to a DC circuit breaker capable of breaking a small current, and a method of breaking the small current thereof. Specifically, the main contact unit is installed at a lower end of the frame, and has a movable contact and a fixed contact. In the DC circuit breaker is installed on the upper end of the frame so as to correspond to the contact unit, and comprises an arc extinguishing chamber for extinguishing the arc current rising through the fixed contact to be divided into a plurality of series arc through a plurality of arcing plate inside The main contact unit further comprises a brow coil assembly installed on the frame so as to be positioned on both sides of the fixed contact and the movable contact. Therefore, according to the present invention configured as described above, by installing the coils on both sides of the contact, and generating a magnetic flux directional to the self induced magnetic flux of the arc current at the trip of the circuit breaker in the coil, it is generated to the self current of the arc It can be applied to the magnetic flux generated by the arc current in the direction of the arc chamber to facilitate the current interruption. Especially, the current is more effective in the small current region up to 0 Amperes (A) below the load current. By cutting off, the arcing time of the breaker can be shortened to minimize the damage of the breaker due to arc heat.

Description

DIRECT CURRENT BREAKER BREAKABLE A LOW CURRENT AND METHOD OF BREAKING THE SAME}

The present invention relates to a DC circuit breaker, and in particular, a coil is provided on both sides of the contact, and the magnetic flux generated in the coil is allowed to go with the magnetic flux generated in the arc current so that the arc current generated between the contacts The present invention relates to a direct current circuit breaker and a small current interruption method capable of short-circuit current with high breaking efficiency in a low current range up to 0A below the rated current, thereby cutting off the current by causing the arcing chamber to be quickly induced.

In general, DC circuit breaker is a circuit breaker used in DC power system. DC high speed circuit breaker, DC quasi-high speed circuit breaker, general type It is divided into DC circuit breaker.

Looking at the configuration of such a DC circuit breaker as shown in Figure 1 and the fixed contact side external connection terminal (3) which is installed on the frame 1, the side of the frame 1, the current is supplied from the bus (not shown) and A main contact unit (5) electrically connected to the fixed contact side external connection terminal (3), installed at the lower portion of the upper surface of the frame (1), and consisting of a fixed contact (not shown) and a movable contact (not shown); It is installed on the side of the frame 1 and driven left and right on the drawing according to the external control, and mechanically coupled to the movable contact of the main contact unit 5, the mechanism to move the movable contact left and right to contact the fixed contact (7), the frame is provided on the side of the frame (1), so as to correspond to the movable contact side external connection terminal (9) electrically connected to the movable contact and supplied with current from the bus bar, and the main contact unit (5). 1) on top Value is consists of extinguishing chamber (11) for extinguishing the arc current generated by the main contact unit (5).

The operation of the DC circuit breaker will be described with reference to FIG. 1. First, when the DC circuit breaker is put in a state where a voltage is applied to the fixed contact side external connection terminal 3 or the movable contact side external connection terminal 9, As the mechanism 7 moves from the left to the right in the drawing by the main circuit (not shown), the movable contact of the main contact unit 5 connected thereto is in contact with the fixed contact so that the movable contact side external connection terminal 9 or the fixed contact The voltage is applied to the power system below via the external connection terminal 3 on the side.

In this state, when the DC circuit breaker is opened, the mechanism 7 is moved from right to left by the force of the internal trip coil and the spring under the control of the main circuit, and the movable contact is separated from the fixed contact, An arc current is generated between the fixed contacts, the arc current rises to the top due to the magnetic induced magnetic flux generated around the arc current, and the injured arc current is led to the extinguishing chamber 11 to be extinguished. do.

On the other hand, if the AC circuit breaker is used in a system that is supplied with a voltage having a frequency of 50 kHz, the current flowing through the main circuit has a natural zero every half cycle (10 ㎳), and thus the arc current generated between the contacts also has a natural zero to cut off the current. This is so easy.

However, since DC breaker does not have a natural zero point, it is difficult to block the current as it must artificially make a zero point for current blocking. Therefore, how quickly DC interruption induces the arc current generated between the contacts into the SOHO chamber to make the forced current zero determines the success or failure of the current interruption. It is influenced a lot by the mechanism. However, in the large current region, when the current value is greater than the rated load current, the magnetic organic magnetic flux due to this arc current is strong, so the arc current is induced into the arc chamber and the arc is easily extinguished due to the large arc resistance in the arc chamber. It is possible to cut off at high speed, but in the low current region where the current value is less than the rated load current, the magnetic flux is relatively weak. Therefore, even if the arc current is difficult to induce into the arc chamber or the induced time is long, the arcing time is long. It will damage the breaker and furthermore, the break will fail.

Thus several techniques have been developed to block these small currents.

One of them is the mechanical force acting during the trip operation of the mechanism by applying the principle of piston to push the generated arc between the contacts into the arc-extinguishing chamber with the compressed air blown through the nozzle as the volume of the cylinder decreases, and the steel around the main contact. By inserting shaped parts to concentrate the magnetic flux generated by the self current of the arc generated between the contacts, and forming the conductor shape of the passage through which the arc current flows into a unique shape such as circular or U-shaped, and the main contact and arc It is installed between the chambers to induce a small current into the arc chamber, and a method of inducing a magnetic field using a permanent magnet. As such, the existing method has a great difficulty in blocking DC small current. Currently, the international standards IEC and ANSI define a threshold current blocking item and require the tester to define an area where the circuit breaker does not block current.

However, among these conventional methods, the compressed air injection method by the air-puffer is effective in blocking the small current, but there are too many design factors to consider such as the position of the nozzle for injecting the compressed air, the size of the nozzle, the direction of the nozzle, and the amount of air injection. In addition, it is inconvenient to repeatedly test the current blocking at all currents, and because it is exposed to the outside, when the nozzle hole is clogged by the dropping of impurities such as accumulated arc residues, it becomes impossible to show its performance. Since the mechanism operation of the breaker is high speed, compressed air is made and injected within a short time, so the air injection time is about 10㎳, and if the arc fails to guide the arc chamber in this short time, the breaker can cut off the current. There is a problem that some degree of risk arises.

In addition, the method of concentrating the magnetic field caused by the arc current by using the steel pieces between the contacts may collect the magnetic fields, but there is another problem that does not help much to induce the injury of the arc.

In addition, the method of inducing an arc current by concentrating a magnetic field by changing a shape such as an external arc horn has another problem that the effect is not excellent compared to a complicated structure and a considerably large part volume.

In addition, the method of using a permanent magnet has no countermeasures in the reverse current inflow due to the voltage change, there is another problem that the potato phenomenon occurs due to arc heat.

Accordingly, an object of the present invention is to solve the above problems, by installing a brow coil on both sides of the contact, and by generating a magnetic flux having a directional magnetic flux of the arc current in the brow coil when the breaker trips, It is useful to cut off the fault system at high speed by shortening the arcing time when the fault current is interrupted by inducing the arc current to the arc chamber by allowing the magnetic flux to become magnetic flux generated by the arc current. In the low current range up to 0A, the magnetic current in the arc current is relatively small, so the magnetic flux is generated in the brow coil, forming a magnetic field in the same direction as the magnetic field caused by the magnetic organic flux in the arc current. The arc is also easily floated into the arc chamber by the brow coil, so the arcing time is shortened To make it easier to block.

1 is a side view schematically showing a configuration of a conventional DC circuit breaker

Figure 2 is an exploded perspective view schematically showing the configuration of a DC circuit breaker capable of breaking a small current according to the present invention

3 is a perspective view showing a combined state of FIG.

Figure 4 is an exploded perspective view showing the configuration of the brow coil assembly of the DC circuit breaker capable of breaking a small current according to the present invention

5 is a side cross-sectional view of the A-A of FIG. 3 for explaining the current direction and the direction of the magnetic flux according to the forward current is applied at the trip of the DC circuit breaker capable of breaking the small current according to the present invention

6 is a side cross-sectional view of the A-A of FIG. 3 for explaining the current direction and the direction of the magnetic flux according to the reverse current is applied when a tripping of the DC circuit breaker capable of breaking the small current according to the present invention

<Description of the symbols for the main parts of the drawings>

1: frame 3: fixed contact side external connection terminal

5: main contact unit 5-1: movable contact

5-2: Fixed Contact 7: Mechanism

9: external contact terminal of movable contact side 11: SOHO room

101: seating hole 103: coupling groove

110: brow coil assembly 111: bobbin

113: coil 115: core

117: insulation housing 119: engaging projection

Features of the present invention for achieving the above object,

A main contact unit installed at a lower portion of the frame, at an upper end of the frame, and having a movable contact and a fixed contact; and an arc current provided at an upper end of the frame so as to correspond to the main contact unit, and rising through the fixed contact. In the DC circuit breaker comprising an arc extinguishing chamber to be extinguished by splitting into a plurality of series arc through a plurality of inner arc plates,

And a brow coil assembly installed on the frame such that the main contact unit is positioned on both sides of the fixed contact and the movable contact.

Here, the upper center portion of the frame,

A seating hole in which the brow coil assembly is seated is formed,

On both sides of the arc chamber,

A coupling groove to which the brow coil assembly is coupled is formed.

Here also the brow coil assembly,

Bobbin,

A coil wound around the outer periphery of the bobbin,

A core of the ferromagnetic material inserted into the central portion of the bobbin,

The bobbin, the coil and the core have a space portion to be accommodated therein, is formed in a T-shape, it is composed of a case formed with a coupling projection coupled to the coupling groove on the back.

Another feature of the invention,

A main contact unit which is installed at a lower part of the frame, at an upper end of the frame, and has a movable contact and a fixed contact, and is installed at an upper end of the frame so as to correspond to the main contact unit, and an arc current rising through the fixed contact. In the small current interruption method of the DC circuit breaker comprising a arc-extinguishing chamber so as to be divided into a plurality of series arc through the arc-extinguishing plate therein.

Brow coil assemblies corresponding to each other are installed on both sides of the main contact unit, and when the current is applied to the coil of the brow coil assembly by a DC voltage supplied from the outside when the DC circuit breaker trips, the magnetic flux is generated. The magnetic flux induced from the arc current generated at the contact point and the fixed contact point and the upper part of the arc are demagnetized, and the lower part is allowed to float to induce the arc current to be guided to the arc chamber.

Here, the coil of the brow coil assembly is

When the breaker is open in the inflow state of the forward or reverse current into the main circuit of the DC circuit breaker, the magnetic flux generated in the brow coil assembly is independent of the current flowing through the main circuit of the DC circuit breaker. The magnetic flux is induced in the arc current generated between the contacts and is electrically connected to the bus line to which the DC circuit breaker is connected so that the arc current is rapidly induced into the arc chamber, so that the arc current can be forced to the arc chamber side. Generates.

Here also the coil of the brow coil assembly,

The magnetic flux generated in the brow coil assembly is independent of the current flowing through the main circuit of the DC circuit breaker when the circuit breaker is opened in the inflow state of the forward or reverse current into the main circuit of the DC circuit breaker. The magnetic flux induced from the arc current generated between the contacts is always allowed to sense the direction of the current flowing into the DC circuit breaker main circuit so that the arc current is rapidly induced into the arc chamber, and the coil current flowing into the brow coil assembly coil is changed and supplied. It is electrically connected to a separate external power supply having an electric circuit to generate a magnetic flux in the direction in which the arc current can be applied to the arc chamber side.

Here again the brow coil assembly,

Excitation time regulation ensures that the arc current is sufficiently induced into the arc chamber and extinguished.

Hereinafter, a configuration of a DC circuit breaker capable of breaking a small current according to the present invention will be described in detail with reference to FIGS. 2 to 4. In FIG. 2 and FIG. 3, the same part as the conventional DC circuit breaker shown in FIG. 1 is attached | subjected with the same code | symbol as FIG. 1, and the description is abbreviate | omitted.

2 is an exploded perspective view schematically showing the configuration of a DC circuit breaker capable of breaking a small current according to the present invention, FIG. 3 is a perspective view showing a coupling state of FIG. 2, and FIG. 4 is a DC capable of breaking a small current according to the present invention. It is an exploded perspective view which shows the structure of the brow coil assembly of a circuit breaker.

2 to 4, the DC circuit breaker 100 capable of breaking the small current according to the present invention is provided on both sides of the fixed contact 5-1 and the movable contact 5-2 of the main contact unit 5. A blow coil assembly 110 is installed in the frame 1 to be positioned. Here, a seating hole 101 in which the brow coil assembly 110 is seated is formed in the upper center portion of the frame 1, and coupling grooves 103 in which the brow coil assembly 110 is coupled to lower ends of both sides of the SOHO chamber 11. ) Is formed.

Here, the brow coil assembly 110 may further include a bobbin 111, a coil 113 wound around the outer periphery of the bobbin 111, a core 115 of a ferromagnetic material inserted into the center of the bobbin 111, and a bobbin. A case 117 having a space part to accommodate the 111 and the coil 113 and the core 115 therein, and having a space portion, and having a T-shape, and having a coupling protrusion 119 coupled to the coupling groove 103 on a rear surface thereof. It consists of.

Here, the winding direction of the coil 113 is wound in a direction in which the generated magnetic flux is caused by the magnetic flux induced by the arc current and the arc current can rise in the upward direction.

Here, the coil of the brow coil assembly 110 changes the direction of the magnetic flux of the brow coil assembly 110 when a constant current or a reverse current flows into the DC circuit breaker 100, thereby releasing the magnetic flux induced by the arc current and the brow coil assembly 110. An electrical circuit that is electrically connected to a bus line (not shown) connected to the DC circuit breaker 100 so as to allow magnetic flux to go through, or senses the direction of the current flowing into the DC circuit breaker 100 to change the direction of the current. Electrical connection with a separate external power supply (not shown) including a contact switch, a switch control circuit, and the like.

Here, the brow coil assembly 110 is preferably provided with a separate time adjustment circuit (not shown) for performing the excitation time adjustment so that the arc current is sufficiently induced by the excitation time control and arc extinguishing.

Hereinafter, a small current blocking method of a DC circuit breaker capable of breaking a small current according to the present invention will be described in detail with reference to FIGS. 5 and 6.

5 is a side cross-sectional view for explaining the current direction and the direction of the magnetic flux according to the constant current is applied when the tripping of the DC circuit breaker capable of breaking the small current according to the present invention, Figure 6 is a DC circuit breaker capable of breaking the small current according to the present invention This is a side cross-sectional view for explaining the current direction and the direction of the magnetic flux as the reverse current is applied at trip.

First, whether the DC circuit breaker 100 is an accidental trip or a normal trip, the DC circuit breaker 100 is opened, and the movable contact 5-2 is opened from the fixed contact 5-1 of the main contact unit 5 during current energization. Arc current c is formed between them. At the same time, a direct current voltage is applied to the coil of each brow coil assembly 110 from a bus or a separate external power supply. At this time, the arc current (c) is a current direction is determined according to the positive and negative directions of the voltage applied to the DC circuit breaker (100).

Then, a coil current corresponding to its impedance flows to each coil 113, and a magnetic field is formed around the coil 113 according to the ampere turn rule, and through the core 115 of the ferromagnetic material installed inside the bobbin 111. Each brow coil assembly 110 leaks N or S magnetic flux d to the outside.

The magnetic flux 29 flowing out of the core 115 is allowed to go without canceling each other with the S or N magnetic flux d generated in the opposite brow coil assembly 110.

Then, the magnetic flux generated in the brow coil assembly 110 is added to the magnetic induced magnetic flux c 'generated in the arc current c itself, so that the upper magnetic flux of the arc current c is demagnetized, and the lower magnetic flux of the arc current c is let go. do.

5, the DC circuit breaker 100 generates an arc current c when the fixed contact 5-1 and the movable contact 5-2 are opened in a state where a constant current is supplied. At this time, the arc current (c) is generated in the direction coming from the ground as shown in Figure 5, thereby forming a magnetic organic magnetic flux (c ') rotated in the counterclockwise direction around the arc current (c).

At the same time, the electric circuit of the external power supply device which detects the direction of the current flowing into the main circuit of the bus bar or the DC circuit breaker 100 and changes the direction of the coil current flowing into the coil 113 of the brow coil assembly 110, is supplied. When a DC voltage is input to the coil 113 of each brow coil assembly 110 through, the current is energized in the coil 113 of the brow coil assembly 110, as shown in FIG. The magnetic flux d flows in the coil assembly direction.

As a result, the magnetic organic magnetic flux c 'caused by the arc current c is affected by the magnetic flux d generated in the brow coil assembly 110. As shown in FIG. The magnetic flux in Es is demagnetized, whereas the magnetic flux in part b, which is downward, becomes lethal. Therefore, the arc current (c) between the fixed contact (5-1) and the movable contact (5-2) is applied in the upward direction according to the principle of the Fleming's left hand law, the arc current (c) itself is induced upward Induced arc current (c) is led to the extinguishing chamber 11 again to be extinguished.

On the other hand, when the reverse current is supplied to the DC circuit breaker 100, if an arc current c is generated, the coil 113 of the brow coil assembly 110 is sensed by detecting a current direction flowing into the main circuit of the bus or DC circuit breaker 100 at this time. When a DC voltage is input to the coil 113 of each brow coil assembly 110 through an electric circuit of an external power supply device that changes the direction of the coil current flowing into the circulating coil current, the brow coil assembly is shown in FIG. 6. The current flows through the coil 113 of 110 so that the magnetic flux d flows from the coil assembly on the right toward the coil assembly on the left.

As a result, the magnetic organic magnetic flux c 'caused by the arc current c is affected by the magnetic flux d generated in the brow coil assembly 110. As shown in FIG. 6, the upward direction of the arc current c is shown. The magnetic flux in part a is demagnetized, whereas the magnetic flux in part b, which is downward, becomes lethal.

As a result, the arc current c between the fixed contact 5-1 and the movable contact 5-2 is forced upward in accordance with the principle of the Fleming's left-hand law, thereby inducing the arc current c upward. Then, the induced arc current (c) is led to the extinguishing chamber 11 again to be extinguished.

Therefore, regardless of the direction of the current flowing in the forward or reverse direction when the DC circuit breaker is open, the arc current generated between the fixed contact point and the movable contact point is rapidly induced into the extinguishing chamber to cut off the circuit of the power system.

As described above, according to the DC circuit breaker and the small current blocking method capable of interrupting the small current according to the present invention, the coil is provided on both sides of the contact, and the magnetic coil of the arc current when the breaker trips in the coil, It generates the magnetic flux having the same directionality, and applies this to the magnetic flux generated by the arc's own current to induce the arc current into the arc chamber to cut off the current. It can be effective.

Claims (7)

A main contact unit installed at a lower portion of the frame, at an upper end of the frame, and having a movable contact and a fixed contact; and an arc current provided at an upper end of the frame so as to correspond to the main contact unit, and rising through the fixed contact. In the DC circuit breaker comprising an arc extinguishing chamber to be extinguished by splitting into a plurality of series arc through a plurality of inner arc plates, And a brow coil assembly installed on the frame so as to be positioned at both sides of the fixed contact and the movable contact of the main contact unit. The method of claim 1, In the upper center portion of the frame, A seating hole in which the brow coil assembly is seated is formed, On both sides of the arc chamber, DC circuit breaker capable of breaking a small current, characterized in that the coupling groove is formed is coupled to the brow coil assembly. The method according to claim 1 or 2, The brow coil assembly, Bobbin, A coil wound around the outer periphery of the bobbin, A core of the ferromagnetic material inserted into the central portion of the bobbin, The bobbin, the coil and the core has a space portion to be accommodated therein, a DC circuit breaker capable of breaking a small current, characterized in that it is formed in a T-shape, the case is formed with a coupling protrusion coupled to the coupling groove on the back. A main contact unit installed at a lower portion of the frame, at an upper end of the frame, and having a movable contact and a fixed contact; and an arc current provided at an upper end of the frame so as to correspond to the main contact unit, and rising through the fixed contact. In the small current interruption method of the DC circuit breaker comprising a arc-extinguishing chamber so as to be divided into a plurality of series arc through the arc-extinguishing plate therein. Brow coil assemblies corresponding to each other are installed on both sides of the main contact unit, and when the current is applied to the coil of the brow coil assembly by a DC voltage supplied from the outside when the DC circuit breaker trips, the magnetic flux is generated. The magnetic flux induced from the arc current generated at the contact point and the fixed contact point and the upper part of the arc are demagnetized, and the lower part is allowed to float so that the arc current is floated to guide the arc chamber. Small current blocking method of DC circuit breaker that can cut current. The method of claim 4, wherein The coil of the brow coil assembly, When the breaker is open in the inflow state of the forward or reverse current into the main circuit of the DC circuit breaker, the magnetic flux generated in the brow coil assembly is independent of the current flowing through the main circuit of the DC circuit breaker. The magnetic flux is induced in the arc current generated between the contacts and is electrically connected to the bus line to which the DC circuit breaker is connected so that the arc current is rapidly induced into the arc chamber, so that the arc current can be forced to the arc chamber side. Small current blocking method of a DC circuit breaker capable of breaking a small current, characterized in that to generate a. The method of claim 4, wherein The coil of the brow coil assembly, When the breaker is open in the inflow state of the forward or reverse current into the main circuit of the DC circuit breaker, the magnetic flux generated in the brow coil assembly is independent of the current flowing through the main circuit of the DC circuit breaker. The magnetic flux induced from the arc current generated between the contacts is always allowed to sense the direction of the current flowing into the DC circuit breaker main circuit so that the arc current is rapidly induced into the arc chamber, and the coil current flowing into the brow coil assembly coil is changed and supplied. Small current cut-off of the DC circuit breaker capable of breaking the small current, characterized in that it is electrically connected to a separate external power supply having an electrical circuit to generate a magnetic flux in the direction that the arc current can be applied to the arc chamber side Way. The method of claim 4, wherein The brow coil assembly, A small current blocking method of a DC circuit breaker capable of breaking a small current, characterized in that the arc current is sufficiently induced by the excitation chamber by controlling the excitation time.