DC circuit

Abstract

To provide a DC circuit capable of reducing the number of components and of exchanging fuses with safety.SOLUTION: Provided is a DC circuit 1 for connecting between a first power supply circuit 30 and a second power supply circuit 50. The DC circuit 1 comprises a wiring circuit breaker 11 and a fuse 17. The wiring circuit breaker 11 at least comprises a primary side first terminal 13b and a primary side second terminal 13c, and at least comprises a secondary side first terminal 15b and a secondary side second terminal 15c at its secondary side. The primary side first terminal 13b is connected at a predetermined position on the first power supply circuit 30. The primary side second terminal 13c is connected with one side of the fuse 17. The secondary side first terminal 15b is connected with the other side of the fuse 17. The secondary side second terminal 15c is connected at a predetermined position on the second power supply circuit 50.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a DC circuit equipped with a circuit breaker and a fuse suitable for use in connecting two circuits. [Background technology]

[0002] In recent years, DC power distribution has come into use due to the widespread use of renewable energy sources such as solar power generation and the proliferation of data centers. Generally, in DC power transmission and distribution, circuit breakers and fuses are used to protect electrical circuits and their electrical elements when an overcurrent occurs. Because circuit breakers and fuses have different interruption characteristics, a circuit may be configured by connecting a circuit breaker and a fuse in series to take advantage of their respective characteristics (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-158092 Summary of the Invention [Problem to be solved by the invention]

[0004] In a circuit configured with a molded-case circuit breaker and a fuse connected in series as described above, if an overcurrent or other problem occurs and the fuse blows, the fuse must be replaced to restore operation. Meanwhile, the circuit connected to the secondary side of such a circuit may be equipped with a power source such as an emergency battery. In such cases, a circuit breaker or similar device must be installed between the fuse and the secondary circuit so that a blown fuse can be replaced without voltage.

[0005] However, providing such an additional circuit breaker increases the number of parts, which leads to increased costs, and also requires space for installing the circuit breaker, which can be difficult to install when the installation space is limited.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a DC circuit that reduces the number of parts and allows fuses to be replaced in a voltage-free state. [Means for solving the problem]

[0007] To achieve the above object, the present disclosure provides the following means. The DC circuit of the present disclosure is a DC circuit connecting a first power supply circuit and a second power supply circuit, the DC circuit comprising a circuit breaker and a fuse, the circuit breaker comprising at least a primary side first terminal and a primary side second terminal on its primary side, and at least a secondary side first terminal corresponding to the primary side first terminal and a secondary side second terminal corresponding to the primary side second terminal on its secondary side, the primary side first terminal being connected to a predetermined location of the first power supply circuit, the primary side second terminal being connected to one side of the fuse, the secondary side first terminal being connected to the other side of the fuse, and the secondary side second terminal being connected to a predetermined location of the second power supply circuit.

[0008] In the DC circuit of the present disclosure, when the circuit breaker is switched to the cutoff state, both ends of the fuse are disconnected from the first power supply circuit and the second power supply circuit, so that the fuse can be replaced in a voltage-free state simply by switching the circuit breaker.

[0009] In the above disclosure, it is preferable that the circuit breaker has a primary side third terminal on its primary side and a secondary side third terminal corresponding to the primary side third terminal, the primary side third terminal being connected to a location different from a predetermined location of the first power supply circuit to which the primary side first terminal is connected, and the secondary side third terminal being connected to a location different from a predetermined location of the second power supply circuit to which the secondary side second terminal is connected.

[0010] By doing this, when the circuit breaker is switched to the cutoff state, the first power supply circuit and the second power supply circuit are disconnected from each other. In other words, by simply switching the circuit breaker, the first power supply circuit and the second power supply circuit can be disconnected and the fuse can be replaced in a voltage-free state. [Effects of the Invention]

[0011] The DC circuit of the present disclosure has the effect of reducing the number of components and providing a DC circuit that allows fuse replacement to be performed safely in a voltage-free state. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a circuit diagram showing a DC circuit according to the present disclosure. [Figure 2] FIG. 2 is a circuit diagram illustrating a conduction state of a DC circuit according to the present disclosure. [Figure 3] FIG. 2 is a circuit diagram illustrating a cutoff state of a DC circuit according to the present disclosure. [Figure 4] Fig. 4(a) is a diagram illustrating an example of a conventional DC circuit, and Fig. 4(b) is a diagram illustrating another example of a conventional DC circuit. DETAILED DESCRIPTION OF THE INVENTION

[0013] A DC circuit according to an embodiment of the present disclosure will be described mainly with reference to Figures 1 to 3. The DC circuit 1 of the present disclosure is a circuit for connecting two power supply circuits, and when an overcurrent or the like flows between the two power supply circuits, it cuts off the current to prevent malfunctions in the connected power supply circuits. The following description will be given assuming that the power supply circuit includes a load circuit equipped with an emergency power supply or the like.

[0014] In this embodiment, an example will be described in which a server system 50 equipped with an emergency power supply 55 is connected to a DC power supply 30 using a DC circuit 1 in, for example, a data center. Note that the use of the DC circuit 1 is not limited to this embodiment. The DC power supply 30 is an example of a first power supply circuit. The server system 50 is an example of a second power supply circuit.

[0015] 1.Configuration Description The DC circuit 1 includes a circuit breaker 11 and a fuse 17. The circuit breaker 11 is a general-purpose circuit breaker also known as an MCCB. The circuit breaker 11 can be switched by a user between a conductive state in which the primary side and secondary side are electrically connected and a cut-off state in which the primary side and secondary side are electrically cut off. The circuit breaker 11 also has a function of automatically switching to a cut-off state when a current exceeding a predetermined threshold flows between the primary side and secondary side in the conductive state. In this embodiment, the following description will be given taking as an example a case in which a circuit breaker with three poles is used as the circuit breaker 11.

[0016] The fuse 17 is a general-purpose fuse that meets the specifications determined by the specifications of the server system 50. The fuse 17 has interruption characteristics different from those of the molded case circuit breaker 11.

[0017] Circuit breaker 11 has primary terminals 13a, 13b, and 13c on its primary side and secondary terminals 15a, 15b, and 15c on its secondary side, respectively. Primary terminals 13a, 13b, and 13c correspond to secondary terminals 15a, 15b, and 15c, respectively. That is, when circuit breaker 11 is in a conductive state, primary terminal 13a is in a conductive state with secondary terminal 15a, primary terminal 13b is in a conductive state with secondary terminal 15b, and primary terminal 13c is in a conductive state with secondary terminal 15c.

[0018] 2. Wiring instructions When the DC circuit 1 is connected between the DC power supply 30 and the server system 50, the primary side of the circuit breaker 11 is connected to the DC power supply 30, and the secondary side of the circuit breaker 11 is connected to the server system 50 (see Figure 1).

[0019] More specifically, primary terminal 13a is connected to electrode 31a at a predetermined location on DC power supply 30 via wiring 21a. Furthermore, primary terminal 13b is connected to electrode 31b at another location on DC power supply 30 via wiring 21b. Furthermore, secondary terminal 15a is connected to electrode 51a at a predetermined location on server system 50 via wiring 23a. Furthermore, secondary terminal 15c is connected to electrode 51b at another location on server system 50 via wiring 23b.

[0020] The primary side terminal 13c is connected to one side of the fuse 17 via a wire 25a. The secondary side terminal 15b is connected to the other side of the fuse 17 via a wire 25b. In this embodiment, the primary side terminal 13b is an example of a primary side first terminal, and the primary side terminal 13c is an example of a primary side second terminal. The secondary side terminal 15b is an example of a secondary side first terminal, and the secondary side terminal 15c is an example of a secondary side second terminal. Furthermore, the primary side terminal 13a is an example of a primary side third terminal, and the secondary side terminal 15a is an example of a secondary side third terminal.

[0021] 3. Description of usage conditions When a predetermined operation is performed and the circuit breaker 11 is brought into a conductive state, the electrode 31a of the DC power supply 30 is electrically connected to the electrode 51a of the server system 50 via the circuit breaker 11. Also, the electrode 31b of the DC power supply 30 is electrically connected to the electrode 51b of the server system 50 via the circuit breaker 11 and the fuse 17 (see FIG. 2). In other words, when the circuit breaker 11 is brought into a conductive state, power is supplied from the DC power supply 30 to the server system 50 via the DC circuit 1.

[0022] When an abnormal current such as an overcurrent flows between the DC power supply 30 and the server system 50, the MCCB 11 goes into an interruption state, electrically disconnecting the DC power supply 30 and the server system 50. Alternatively, the fuse 17 melts, electrically disconnecting the electrode 31b and the electrode 51b. Specifically, the MCCB 11 goes into an interruption state or the fuse 17 melts depending on the characteristics of the abnormal current such as an overcurrent flowing between the DC power supply 30 and the server system 50, the interruption characteristics of the MCCB 11, and the interruption characteristics of the fuse 17.

[0023] In this way, when an abnormal current such as an overcurrent flows, the DC circuit 1 operates according to the characteristics of the abnormal current, thereby preventing malfunctions and the like from occurring in the DC power supply 30 and the server system 50.

[0024] 4. Fuse replacement instructions Next, a description will be given of the operation of replacing the fuse 17. In the following description, an example will be given in which the molded case circuit breaker 11 is in a conductive state when the fuse 17 melts due to an overcurrent.

[0025] Since the circuit breaker 11 is in a conductive state, the voltage on the electrode 31b side of the DC power supply 30 appears on one side of the fuse 17 via the wires 21b and 25b. In addition, since the server system 50 is equipped with an emergency power supply 55, the voltage on the electrode 51b side of the server system 50 appears on the other side of the fuse 17 via the wires 23b and 25a.

[0026] Therefore, when replacing the fuse 17, the worker performing the replacement work operates a switch (not shown) or the like of the circuit breaker 11 to switch the circuit breaker 11 to the cutoff state before performing the work (see FIG. 3). When the circuit breaker 11 is switched to the cutoff state, the DC power supply 30 and the server system 50 are electrically disconnected from each other. In addition, the fuse 17 is electrically disconnected from both the DC power supply 30 and the server system 50.

[0027] After replacing the fuse 17, the worker operates a switch (not shown) of the circuit breaker 11 to switch the circuit breaker 11 to a conductive state. When the circuit breaker 11 switches to a conductive state, the electrode 31a of the DC power supply 30 is electrically connected to the electrode 51a of the server system 50 via the circuit breaker 11. Also, the electrode 31b of the DC power supply 30 is electrically connected to the electrode 51b of the server system 50 via the circuit breaker 11 and the fuse 17 (see FIG. 2). That is, the DC power supply 30 and the server system 50 are electrically connected again.

[0028] In the DC circuit 1 configured as described above, when the circuit breaker 11 is switched to the cutoff state, both ends of the fuse 17 are disconnected from both the DC power supply 30 and the server system 50. Therefore, by simply switching the circuit breaker 11, the fuse 17 can be replaced without any voltage appearing across it.

[0029] For example, in the conventional DC circuits 100A and 100B shown in Figures 4(a) and 4(b), even if the MCCB 11 is set to an interrupted state, the fuse 17 cannot be disconnected from one of the power supply circuits, the second power supply circuit 50. For this reason, it was necessary to provide a circuit breaker 70 between the MCCB 11 and the power supply circuit 50 in order to replace the fuse 17.

[0030] On the other hand, in the DC circuit 1 of this embodiment, when the molded case circuit breaker 11 is switched to the cutoff state, both ends of the fuse 17 are disconnected from the DC power supply 30 and the server system 50. Therefore, there is no need to provide a circuit breaker 70 as provided in the conventional DC circuits 100A, 100B, etc. In other words, a DC circuit with a reduced number of parts can be configured. Furthermore, since there is no need to provide an additional circuit breaker 70, a compact DC circuit can be achieved.

[0031] Furthermore, when the MCCB 11 is switched to the cutoff state, an electrical disconnection occurs between the DC power supply 30 and the server system 50. That is, simply by switching the MCCB 11 to the cutoff state, the DC power supply 30 and the server system 50 are cut off, and both ends of the fuse 17 are disconnected from the DC power supply 30 and the server system 50, respectively. That is, the fuse 17 can be replaced safely with a simple operation and in a voltage-free state.

[0032] Furthermore, in the conventional DC circuits 100A and 100B illustrated in FIGS. 4(a) and 4(b), if the operator forgets to switch either the MCCB 11 or the circuit breaker 70 to the cutoff state, voltage will appear on one side of the fuse 17. In other words, if the operator forgets to switch either the MCCB 11 or the circuit breaker 70 to the cutoff state, the fuse 17 will have to be replaced with voltage still present. On the other hand, in the DC circuit 1 of this embodiment, it is only necessary to switch the MCCB 11 to the cutoff state, so this situation can be prevented from occurring. In other words, it is possible to prevent the operator from accidentally replacing the fuse with voltage still present.

[0033] The present disclosure is not limited to the above embodiments as long as it conforms to the spirit of the disclosure described in the above embodiments. Various modifications can be made without departing from the spirit of the present disclosure. For example, in the above embodiment, the DC circuit 1 is used to connect the server system 50 equipped with the emergency power supply 55 to the DC power supply 30, but the DC circuit 1 may also be used to connect other power supply circuits. For example, the DC circuit 1 may also be used to connect a power supply circuit included in a solar power generation system.

[0034] In the above embodiment, the case where the circuit breaker 11 is a circuit breaker with three poles has been described as an example, but a circuit breaker with four or more poles may also be used. In this way, it becomes possible to connect two power supply circuits with more wiring. Alternatively, a circuit breaker with two poles may be used as the circuit breaker 11. In this way, it is possible to create a DC circuit with a simpler configuration that allows the fuse 17 to be replaced safely in a voltage-free state.

[0035] Also, instead of the circuit breaker 11, a known device having a similar function for protecting a circuit from overcurrent may be used. Alternatively, instead of the fuse 17, another known electric element that prevents current exceeding a predetermined threshold from flowing may be used. [Explanation of symbols]

[0036] 1... DC circuit 11... Circuit breaker 13a, 13b, 13c... Primary side terminals 15a, 15b, 15c...Secondary terminals 17...Fuse 21a, 21b, 23a, 23b, 25a, 25b...Wiring 30...DC power supply 31a,31b,51a,51b...electrode 50...Server system 55...Emergency power supply

Claims

1. A DC circuit connecting a first power supply circuit and a second power supply circuit, The DC circuit is Equipped with a circuit breaker and fuse, the circuit breaker has at least a primary side first terminal and a primary side second terminal on its primary side, and at least a secondary side first terminal corresponding to the primary side first terminal and a secondary side second terminal corresponding to the primary side second terminal on its secondary side; the primary side first terminal is connected to a predetermined location of the first power supply circuit, the primary side second terminal is connected to one side of the fuse; the secondary-side first terminal is connected to the other side of the fuse; the secondary-side second terminal is connected to a predetermined location of the second power supply circuit; DC circuit.

2. the circuit breaker has a primary-side third terminal on its primary side and a secondary-side third terminal corresponding to the primary-side third terminal on its secondary side; the primary-side third terminal is connected to a location of the first power supply circuit different from a predetermined location to which the primary-side first terminal is connected, the secondary-side third terminal is connected to a location of the second power supply circuit different from a predetermined location to which the secondary-side second terminal is connected; 2. The DC circuit of claim 1.

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