KR100628596B1 - Current limiting circuit breaker using multiple PTC device - Google Patents

Abstract

The present invention relates to a current-limiting circuit breaker using a plurality of PTC elements. The breaker according to the present invention is connected to the power system, the first blocking portion for blocking the line when an accident current occurs; A second cut-off part connected in parallel with the first cut-off part and sequentially blocking a line after the cut-off of the first cut-off part in the event of an accident current; and connected in parallel with the first cut-off part and connected in series with the second cut-off part, And a plurality of PTC units including a plurality of PTC elements so as to be connected to each other by switching from one PTC element to another PTC element through a common terminal when the first blocking unit and the second blocking unit are reconnected.

According to the present invention, the PTC device can operate normally to limit the fault current even if the break switch is closed again before the PTC device which has faulted the fault current is cooled.

Description

Current limiting circuit breaker using multiple PTC devices

The following drawings attached to this specification are illustrative of preferred embodiments of the present invention, and together with the detailed description of the invention to serve to further understand the technical spirit of the present invention, the present invention is a matter described in such drawings It should not be construed as limited to

1 is a circuit diagram of a conventional current-limiting circuit breaker using a PTC element.

2 is a circuit diagram of a current-limiting circuit breaker using a plurality of PTC elements according to a preferred embodiment of the present invention.

3 to 5 are circuit diagrams illustrating a sequential operation state of a current-limiting circuit breaker using a plurality of PTC elements according to a preferred embodiment of the present invention.

The present invention relates to a current-limiting circuit breaker using a PTC element, and more particularly, even if the breaker switch is closed again before the PTC (Positive Temperature Coefficient) element that has faulted the fault current is cooled. The present invention relates to a current-limiting circuit breaker capable of limiting current.

An electrical protection system is called a circuit breaker to prevent the destruction of a wiring or connected equipment or the occurrence of fire by breaking the line quickly when an overcurrent or short-circuit current (hereinafter referred to as 'accident current') occurs on the line. The breaker is provided with a bonded switch, and when the accident occurs on the track, the contact of the switch is opened by the electromagnetic repulsive force to cut off the accident current. However, when the circuit breaker operates to cut off the circuit where the accident current flows, the arc generated between the contacts of the opened switch has an explosive expansion pressure with its center temperature reaching 8,000 ~ 12,000 ℃, so it melts and consumes the contacts of the switch. There is a problem of deteriorating and destroying the insulator. To solve this problem, a current-limiting circuit breaker using a PTC device has been proposed.

 When a current exceeding the allowable current flows, the PTC element is heated by Joule heat and the temperature rises. When the element exceeds the critical temperature, the resistance is rapidly increased to cut off the electrically connected circuit to protect the circuit.

1 is a circuit diagram of a current-limiting circuit breaker 10 using a conventional PTC element. Referring to the drawings, the current-limiting circuit breaker 10 includes a first interruption unit 11 connected to a power system, a PTC element 12 connected in parallel to the first interruption unit 11, and the first interruption unit 11. Is connected in parallel and the PTC element 12 is composed of a second blocking portion 13 connected in series.

Looking at the operation of the current-limiting circuit breaker 10 having such a configuration, if an accident occurs in the power system and the current flows in the line, the first blocking portion 11 of the current-limiting circuit breaker is opened by electromagnetic repulsive force and the line is cut off. Then, the fault current can no longer flow to the blocked line side and is bypassed to the line side on which the PTC element 12 is installed. As a result, the temperature of the PTC element 12 suddenly rises due to Joule heat caused by the bypassed accident current, and when the temperature of the PTC element 12 exceeds the threshold temperature, the resistance of the PTC element 12 increases rapidly. The fault current on the line is limited. When the fault current is limited in this way, the contact of the second breaker 13 is mechanically opened within a predetermined time to complete the fault current.

As described above, the accident recovery is performed while the first blocking part 11 and the second blocking part 13 are sequentially tripped, and the temperature of the PTC device 12 is lowered to be equal to or lower than the critical temperature of the device during the accident recovery. As it is cooled down, the PTC element 12 returns to the initial small resistance value. Therefore, when the first breaker 11 and the second breaker 12 of the breaker are closed again after the accident recovery, the normal load current flows through the line.

However, if the first breaker 11 and the second breaker 12 of the breaker are closed again after the line is shut off but before the PTC element 12 is cooled, the PTC element 12 may have a resistance value. Because of maintaining a large state, there is a problem that does not effectively limit the fault current. In particular, if the breaker is closed again in a state where a second accident occurs or the cause of the accident is not completely removed after the line is blocked due to the occurrence of an accident, the concern of the occurrence of the problem is further increased.

The present invention has been made to solve the above problems, and a plurality of PTC devices capable of limiting the fault current by operating the PTC device normally even if the break switch is closed again before the PTC device which has faulted the fault current is cooled. The purpose is to provide a current-limiting circuit breaker.

The current-limiting circuit breaker using a plurality of PTC elements in accordance with the present invention for achieving the technical problem, is connected to the power system to cut off the line in the event of an accident current; A second cut-off part connected in parallel with the first cut-off part and sequentially blocking a line after the cut-off of the first cut-off part in the event of an accident current; and connected in parallel with the first cut-off part and connected in series with the second cut-off part, And a plurality of PTC units including a plurality of PTC elements so as to be connected to each other by switching from one PTC element to another PTC element through a common terminal when the first blocking unit and the second blocking unit are reconnected.

In the current-limiting circuit breaker using a plurality of PTC elements according to the present invention, the multiple PTC unit is provided with a plurality of storage spaces for accommodating the PTC therein, the rotary housing rotatable about a central axis; A plurality of PTC elements accommodated in the storage space; and a common terminal connected to the first blocking portion or the second blocking portion.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the specification and claims should not be construed as having a conventional or dictionary meaning, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention. Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiment of the present invention and do not represent all of the technical idea of the present invention, it is possible to replace them at the time of the present application It should be understood that there may be various equivalents and variations.

2 is a circuit diagram of a circuit breaker using a plurality of PTC devices according to a preferred embodiment of the present invention. Referring to the drawings, multiple PTC portions 30 having a plurality of PTC elements 33 and 34 are connected to the first blocking portion 20 and the second blocking portion 40.

The first blocking portion 20 is a switch having a pair of contacts, and the switch is closed in a normal state, and serves as a path for load current. However, when an accident occurs in the power system and an accident current flows between the contacts of the first blocking unit 20, an electromagnetic repulsive force is generated between the contacts, thereby opening the contact, and thus the first blocking unit 20. The line connected to is cut off. Therefore, the accident current can no longer flow through the first blocking portion 20, and is classified into the multiple PTC portions 30 as described later.

The multiple PTC unit 30 is connected in parallel to the first blocking unit 20 to limit the fault current when an accident occurs. On the other hand, since the multiple PTC unit 30 includes a plurality of PTC elements 33 and 34 instead of one PTC element, the blocking unit (1) after the sequential trip of the first blocking unit 20 and the second blocking unit 40. When the 20 and 40 are closed again, the new PTC device can be connected to the first breaker 20 and the second breaker 40 of the circuit breaker, not the PTC device that has faulted the fault current.

Therefore, the multiple PTC unit 30 includes a rotary housing 31 rotatable about a central axis and a plurality of PTC elements 33 and 34 accommodated in the internal space of the rotary housing 31.

The rotary housing 31 is preferably made of a cylindrical shape so as to be rotatable by the rotary switch 32 provided on one surface of the rotary housing 31. A plurality of storage spaces are provided in the rotary housing 31 to accommodate the plurality of PTC elements 33 and 34.

Referring to the drawing, since the multiple PTC unit 30 accommodates two PTC elements 33 and 34, the rotary switch 32 may be rotated 180 ° so that the new PTC element is connected to the line. Of course, in other embodiments, multiple PTC units 30 may include three or four PTC elements, in which case the rotary switch 32 is rotated 120 ° or 90 ° so that the new PTC element is connected to the line. You may.

The input terminal and the output terminal of the first PTC element 33 and the second PTC element 34 are connected to the first blocking part 20 and the second blocking part 40 of the line, respectively. The outer peripheral surface of the rotary housing 31 is provided with a common input terminal 35 connecting the input terminals of the first PTC element 33 and the second PTC element 34, so that the PTC element 33 even if the rotary housing 31 rotates. 34, the input terminal is always connected to the first blocking unit (20). Therefore, even if the rotary housing 31 is rotated, all the received PTC elements 33 and 34 are connected to the first blocking portion 20 via the common input terminal 35, but the second blocking portion 40 Only the output terminal of one PTC element is connected.

In the above-described embodiment, the embodiment in which the common input terminal 35 of the PTC elements 33 and 34 is provided on the outer circumferential surface of the rotary housing 31 is described. However, the present invention is not limited thereto, and the outer circumferential surface of the rotary housing 31 is not limited thereto. Also included is an embodiment in which the common output terminals of the PTC elements 33 and 34 are provided so that the output terminals of the PTC elements 33 and 34 are always connected to the second interruption unit 40 even when the rotary housing 31 is rotated. Of course.

According to the present invention, even if the breaker is re-inserted in a state where the cause of the accident is not completely eliminated, a new second PTC element is not connected to the line because the cooling is not yet performed and the first PTC element 33 having a high resistance value is not connected to the line. 34 can be connected. Therefore, the electrical characteristics of the PTC device connected to the line is always maintained in a normal state, so that the fault current of the fault current can be smoothly performed.

Hereinafter, the operation of the current-limiting circuit breaker 100 configured as described above will be described in detail with reference to FIGS. 3 to 5. When an accident current flows in the current-limiting circuit breaker 100, the first blocking portion 20 of the circuit breaker is opened to cut the line. Then, the fault current is bypassed through the first PTC element 33 of the multiple PTC unit 30, and the fault current of the line is limited while the resistance of the first PTC element 33 is rapidly increased by the fault current. When the fault current is limited in this way, the contact of the second cut-off unit 40 is mechanically opened within a predetermined time to complete blocking the fault current. Before reconnecting the breaker in a state where the line is blocked by the first blocking portion 20 and the second blocking portion 40, the rotary switch 32 of the multiple PTC portion 30 is shown in FIG. To rotate the rotary housing 31.

Then, as shown in FIG. 4, the positions of the first PTC element 33 which has caused the fault current to be limited and the second PTC element 34 not connected to the line are changed, so that the second PTC element 34 is connected to the second blocking portion ( It is placed at the connection position of 40).

Then, as shown in FIG. 5, when the first blocking part 20 and the second blocking part 40 of the circuit breaker are connected again, the second PTC element 34 is connected to the line. Even if it is not cooled, the newly connected second PTC element 34 can smoothly fault the fault current. On the other hand, since the first PTC element 33 removed from the line can secure a sufficient cooling time, even if the second PTC element 34 which has a fault current current is removed from the line and then connected to the line again, the first PTC element 33 Can limit the fault current. Of course, the newly connected PTC device is not the first PTC device 33 removed from the line, but may be another PTC device of the multiple PTC unit 30 including three or more PTC devices as described above.

In the above-described embodiment, a method of connecting a new PTC device has been described as a manual method using a rotary switch. However, the present invention is not limited thereto, and the solenoid is applied by applying a control current to the solenoid connected to the second cut-off part 40 when an accident occurs. The second blocking portion 40 may be switched to the output terminals of the plurality of PTC elements 33.34 by the suction force of. Since such a configuration is well-known technology, detailed description thereof will be omitted. In addition, various switch switching means may be employed.

The technical problem of the present invention is achieved by the above technical configuration, and although the present invention has been described by the limited embodiments and the drawings, the present invention is not limited by this and the general knowledge in the technical field to which the present invention belongs. It is apparent that various modifications and variations can be made by those skilled in the art within the scope of the technical spirit of the present invention and the claims to be described below.

According to the present invention, even if the break switch is closed again before the PTC device which has faulted the fault current is cooled, the PTC device can operate normally to limit the fault current, so that the cause of the fault is not completely removed after the line is disconnected according to the fault current. Even if the fault current is regenerated by a fault or other fault, the PTC device can operate normally to protect the power equipment according to the fault current.

Claims (2)

A first cut-off unit connected to a power system to cut off a line when an accident current occurs; A second cut-off part connected in parallel with the first cut-off part and sequentially blocking a line after the cut-off of the first cut-off part when an accident current occurs; and A plurality of parallel connection to the first interruption unit and a series connection to the second interruption unit, such that the plurality of PTC elements are switched from one PTC element to the other PTC element via a common terminal when reconnecting the first interruption unit and the second interruption unit; Multiple PTC unit comprising a PTC element of the current-limiting circuit breaker using a plurality of PTC elements comprising a. The method of claim 1, The multiple PTC unit, A rotary housing provided therein with a plurality of accommodation spaces for accommodating the PTC and rotatable about a central axis; A plurality of PTC elements housed in the storage space; and And a common terminal connected to the first blocking portion or the second blocking portion.

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