Device

Abstract

This device comprises: a first one-way breaker unit disposed on the first direction side of a power line; a second one-way breaker unit disposed on the second direction side of the power line; and a third one-way breaker unit disposed on a branch line side, the branch line extending from a branch point of the power line.

Description

Device

[0001] The present invention relates to protection and coordination of power supply systems.

[0002] In general, in power supply systems, protective coordination is implemented by appropriately setting the settings of circuit breaker sensitivity, operating time, etc., so that in the event of an accident, the faulty part can be quickly isolated and other healthy circuits can be protected.

[0003] For example, if a short circuit occurs in a section of a power line near a load connected to the end of a power supply system, a very large short-circuit current will usually flow through the power line, causing a circuit breaker to instantly operate and disconnect the short-circuited area from the power supply.

[0004] Meanwhile, in recent years, the introduction of ring-type (also referred to as loop-type) power supply systems has been progressing in various regions (for example, Non-Patent Document 1). A ring-type power supply system is a power supply system in which various power sources (such as photovoltaic power generation (PV)), storage batteries, electric vehicles (EVs), etc. are connected in a ring shape with power lines. In such a power supply system, protection coordination is achieved by "cascade tripping" using multiple circuit breakers. Cascade tripping is a mechanism in which, in an electrical system where an accident has occurred, circuit breakers are set to trip equipment in order, starting from the lower-level (load side), in order to minimize the scope of the power outage.

[0005] Summary of opinions on issues related to the construction of regional microgrids and the implementation of power distribution projects (Ministry of Economy, Trade and Industry) https: / / www.meti.go.jp / shingikai / energy_environment / energy_resource / pdf / 015_04_00.pdf (accessed November 30, 2023)

[0006] As mentioned above, storage batteries are generally connected to ring-type power supply systems. However, because storage batteries act as a higher-level power source (power source) when discharging and as a lower-level load (load) when charging, the direction and route of current flow cannot be uniquely determined in a power supply system with storage batteries connected.

[0007] Therefore, it has been difficult to achieve protection coordination in a ring-type power supply system connected to storage batteries. Note that this issue is not limited to ring-type power supply systems, but can occur in any power supply system connected to storage batteries.

[0008] The present invention has been made in view of the above points, and an object of the present invention is to provide a technique that enables appropriate protection coordination in a power supply system.

[0009] According to the disclosed technology, there is provided a device comprising: a first unidirectional interrupter arranged on a first direction side of a power line; a second unidirectional interrupter arranged on a second direction side of the power line; and a third unidirectional interrupter arranged on a branch line side extending from a branch point on the power line.

[0010] According to the disclosed technology, a technology is provided that enables appropriate protection coordination in a power supply system.

[0011] 1 is a diagram illustrating an example of the configuration of a star-type power supply system. FIG. 2 is a diagram illustrating an example of the configuration of a ring-type (loop-type) power supply system. FIG. 3 is a diagram illustrating an example of the configuration of a power supply system according to an embodiment of the present invention. FIG. 4 is a diagram illustrating an example of a unidirectional breaking unit. FIG. 5 is a diagram illustrating an example of a bidirectional breaking unit. FIG. 6 is a diagram illustrating an example of the configuration of a three-way circuit breaker 300. FIG. 7 is a diagram illustrating an example of a power supply system in which three bidirectional breaking units are arranged around a branch point. FIG. 8 is a diagram illustrating an example of the configuration of a power supply system according to an embodiment of the present invention. FIG. 9 is a diagram illustrating a determination condition. FIG. 10 is a diagram illustrating a determination condition. FIG. 11 is a diagram illustrating a detailed configuration example of the three-way circuit breaker 300. FIG. 12 is a diagram illustrating an example of setting values ​​of each breaking unit. FIG. 13 is a diagram illustrating a processing flow of the three-way circuit breaker 300. FIG. 14 is a diagram illustrating a basic operation example. FIG. 15 is a diagram illustrating a basic operation example. FIG. 16 is a diagram illustrating a specific example of the flow from measurement to control in the three-way circuit breaker 300. FIG. 17 is a diagram illustrating an example of a loop-wired power supply system. FIG. 18 is a diagram illustrating an example of a bus-wired power supply system. FIG. 19 is a diagram illustrating an example of the configuration of a three-way circuit breaker 300 according to a modified example. FIG. 19 is a diagram illustrating the effectiveness of the number of semiconductor elements. FIG. 19 is a diagram illustrating operation example 1 according to a modified example. Fig. 10 is a diagram for explaining an operation example 2 in a modified example. ...1 in a modified example. Fig. 10 is a diagram for explaining an operation example 2 in a modified example. Fig. 10 is a

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The embodiment described below is merely an example, and the embodiment to which the present invention is applied is not limited to the following embodiment.

[0013] The power supply system described below is a DC power supply system, but the application of the technology according to the present invention is not limited to DC power supply systems.

[0014] (Regarding the Issues) Conventional power supply systems include, for example, star-type power supply systems and ring-type power supply systems. Star-type power supply systems are mainly used to supply power indoors. Ring-type power supply systems are used not only to supply power indoors but also to supply power to outdoor devices such as EVs.

[0015] An example of the configuration of a star-type power supply system is shown in Fig. 1. The power supply system shown in Fig. 1 is a power supply system that supplies power in one direction from customer building A to customer building B, customer building C, and customer building D.

[0016] As shown in Figure 1, in this power supply system, a circuit breaker is installed in each system. This makes it possible to open only the circuit breaker of the system in which a short circuit occurs, and isolate the short circuit point from the electrical circuit. The example in Figure 1 shows a case in which a short circuit occurs in the system to which customer building D is connected. In this system, there is no need for protective coordination. Examples of circuit breakers that can be used include fuses, CBs (Circuit Breakers), and DC circuit breakers. Examples of DC circuit breakers include mechanical circuit breakers, semiconductor circuit breakers (which may also be called semiconductor circuit breakers), and hybrid circuit breakers, which are a hybrid of mechanical and semiconductor circuit breakers.

[0017] An example of the configuration of a ring-type (or loop-type) power supply system is shown in Fig. 2. As shown in Fig. 2, this power supply system is a power supply system in which various power sources (such as photovoltaic power generation (PV)), storage batteries, electric vehicles (EVs), etc. are connected in a ring shape by power lines.

[0018] This power supply system is equipped with multiple circuit breakers. Protection coordination is achieved through "cascade tripping" consisting of multiple circuit breakers. As mentioned above, cascade tripping is a mechanism in which circuit breakers are set to trip equipment in order, starting with the lower-level (load side) equipment in an electrical system in the event of an accident, in order to keep the scope of the power outage as small as possible. In cascade tripping, circuit breakers connected to lower levels must trip the current faster (shorter time after the accident occurs) than circuit breakers connected to higher levels.

[0019] In the prior art, as shown in FIG. 2 , it is conceivable that the circuit breakers are classified as upper / lower based solely on their placement on the power supply system, and that setting values ​​(e.g., current value, voltage value, time limit (hours), etc.) are set for the upper circuit breaker 1 and the lower circuit breaker 2 so that the lower circuit breaker 2 trips before the upper circuit breaker 1.

[0020] However, because storage batteries generally connected to a ring-type power supply system act as a host (power source) when discharging and as a host (load) when charging, the direction and route of current in a power supply system connected to a storage battery are not uniquely determined. This makes it difficult to achieve protection coordination by setting the circuit breaker settings based on the concept of "cascade breaking" during design.

[0021] The configuration and operation of a system that solves the above problems will be described below.

[0022] (Example of Overall System Configuration) Fig. 3 shows an example of the configuration of a power supply system according to this embodiment. As shown in Fig. 3, in the power supply system according to this embodiment, a three-way circuit breaker 300 is provided at a branch point, which is an intersection of a trunk line and a branch line extending to a consumer. The "three-way circuit breaker 300" may also be referred to as a "device."

[0023] In this embodiment, a semiconductor circuit breaker having a semiconductor element is used as the circuit breaker, which is a component of the three-way circuit breaker 300, and therefore the three-way circuit breaker 300 may be called a "three-way semiconductor circuit breaker 300." However, the configuration of the three-way circuit breaker 300 is not limited to one that uses a semiconductor circuit breaker.

[0024] Each consumer may have any of a load, a storage battery, a power generation device using renewable energy, an EV (electric vehicle), etc. However, in this embodiment, it is assumed that at least one of the multiple consumers is a storage battery.

[0025] Each three-way circuit breaker 300 in this embodiment includes three unidirectional circuit breaking units, each capable of breaking one of two currents flowing through the unidirectional circuit breaking unit. The unidirectional circuit breaking units are capable of performing a breaking operation based on a set value (e.g., current value, voltage value, time limit (hours), etc.) corresponding to the direction of the current. The following mainly describes, as an example, a case where a current threshold value is used as the set value.

[0026] For example, when a current flows from consumer B to consumer A, the threshold (interruption threshold) of the one-way interrupter connected to the branch line of consumer A can be set to be smaller than the thresholds of any one-way interrupters on the path of that current that can interrupt the direction of that current flow. This allows, for example, if a short circuit occurs on the branch line connected to consumer A, the one-way interrupter connected to consumer A to quickly interrupt the current. Furthermore, if the way the current flows changes, appropriate cooperative operation can be performed by setting a threshold according to the changed current.

[0027] As will be described later, within the three-way circuit breaker 300, a bidirectional circuit breaker may be used for the circuit breaker connected to the branch line.

[0028] (Regarding the unidirectional cutoff unit and the bidirectional cutoff unit) Here, examples of the unidirectional cutoff unit and the bidirectional cutoff unit will be described. Fig. 4 shows an example of a unidirectional cutoff unit. As shown in Fig. 4, the unidirectional cutoff unit has one semiconductor element such as a MOSFET and parts indicated by A and B. A is, for example, a diode, and B is, for example, a capacitor.

[0029] An example of a bidirectional cutoff unit is shown in Figure 5. As shown in Figure 5, the bidirectional cutoff unit has two semiconductor elements such as MOSFETs and parts indicated by A to D. The two semiconductor elements are connected in series in the opposite directions. A and D are, for example, diodes, and B and C are, for example, capacitors.

[0030] The one-way interrupting section may be called a one-way semiconductor circuit breaker, and the two-way interrupting section may be called a two-way semiconductor circuit breaker.

[0031] (Example of a schematic configuration of a three-way circuit breaker 300) Fig. 6 shows an example of the configuration of the three-way circuit breaker 300. As shown in Fig. 6, the three-way circuit breaker 300 includes a control device 100, a measurement unit 200, circuit breaker units 10, 20, and 30, a power input / output terminal 301, and a communication input / output terminal 302. As shown in a more detailed diagram described later, the control device 100 includes a communication unit 110, a calculation unit 120, and a control unit 130. The control device 100 may be located outside the three-way circuit breaker 300.

[0032] The measurement unit 200 measures the direction and magnitude of the current flowing through each interrupter. An image of a current transformer (CT) is shown in FIG.

[0033] When the direction of the current is a predetermined direction and the magnitude of the current exceeds a cutoff threshold, the control unit 130 executes control to open the corresponding cutoff unit. Note that opening the cutoff unit may also be referred to as cutting off the current.

[0034] More specifically, the calculation unit 120 performs calculations for determining the determination conditions, etc., which will be described later, and the control unit 130 controls the cutoff unit based on the determination results by the calculation unit 120 .

[0035] The communication unit 110 can output information indicating the state of the three-way circuit breaker 300. The communication unit 110 may also be used to change the tripping threshold value or to update software.

[0036] In this embodiment, the consumer is provided with a bidirectional DC / DC converter, which is connected to the branch line. The communication unit 110 communicates with the bidirectional DC / DC converter to acquire information from the bidirectional DC / DC converter and control the overcurrent protection function of the bidirectional DC / DC converter. The bidirectional DC / DC converter can perform operations such as cutting off current flowing from the consumer to the main line.

[0037] Each of the three interrupting units 10, 20, and 30 is a one-way interrupting unit that interrupts current in one direction. Figure 6 shows an example of the current detection direction and threshold current value for each interrupting unit. Note that the thresholds for the interrupting units 10 and 20 are assumed to be constant, but can be manually fine-tuned.

[0038] 6, the interrupter 10 is provided between the trunk line extending to the left and the branch point, the interrupter 20 is provided between the trunk line extending to the right and the branch point, and the interrupter 30 is provided between the customer and the branch point.

[0039] The configuration shown in FIG. 6 makes it possible to protect against a short circuit (internal short circuit) occurring at a branch point inside the three-way circuit breaker 300.

[0040] (Regarding the Number of Semiconductor Elements) Instead of using the three-way circuit breaker 300 having three one-way circuit breakers as shown in FIG. 6, it is also possible to use three two-way circuit breakers as shown in FIG.

[0041] Figure 7 shows an example of a power supply system in which three bidirectional cutoff units are arranged around a branch point. Figure 7 also shows an example of the direction of current flowing through each semiconductor element (e.g., MOSFET) and its cutoff threshold. In the part shown in Figure 7, there are eight semiconductor elements on the trunk line.

[0042] However, if the number of branch lines (= branch points) connected to the trunk line increases, many semiconductor elements will be connected in series to the current path, which will increase the conduction loss in the semiconductor elements and the number of parts.

[0043] Therefore, in this embodiment, instead of a configuration using three bidirectional cutoff units, a configuration including three unidirectional cutoff units is adopted as shown in Fig. 6. Note that the cutoff units connected to the branch lines may also be bidirectional cutoff units.

[0044] Fig. 8 shows an example of the configuration of a power supply system according to this embodiment. Fig. 8 shows the same current situation as Fig. 7. As shown in Fig. 8, in the power supply system according to this embodiment, a three-way circuit breaker 300 is provided on each of the consumer A side and the consumer B side.

[0045] In the power supply system of this embodiment, control is performed by communication between the three-way circuit breaker 300 and the bidirectional DC / DC converter. Furthermore, the three-way circuit breaker 300 itself determines whether or not there is short circuit protection within the three-way circuit breaker 300. The determination logic will be described later.

[0046] As described above, by using three-way circuit breaker 300 according to this embodiment, the number of semiconductor elements can be reduced compared to the configuration shown in Fig. 7. Furthermore, three-way circuit breaker 300 can provide protection against a short circuit (internal short circuit) that occurs at an internal branch point.

[0047] In this embodiment, communication is performed between the three-way circuit breaker 300 and the bidirectional DC / DC converter to monitor the state of the bidirectional DC / DC converter and control the threshold value of the overcurrent protection (OCP). This makes it possible to control the output current from the consumer even if there is no upward unidirectional circuit breaker on the branch line.

[0048] Furthermore, by setting the interruption threshold of the interrupting unit 30 connected to the branch line lower than the interruption threshold of the one-way interrupting units 10 and 20 connected to the main line, if a short circuit occurs in the branch line, the interrupting unit 30 can be operated before the main line.

[0049] In addition, the tripping threshold of each circuit breaker can be finely adjusted manually or remotely (e.g., in 1 A intervals), and in the case of a bus-wired or loop-wired system, the tripping thresholds of circuit breakers 10 and 20 can be shifted from the tripping thresholds of the three adjacent circuit breakers on the main line to enable protection coordination of the main line.

[0050] In other words, by using three-way circuit breaker 300 according to this embodiment, the number of semiconductor devices installed on the trunk line and branch lines can be reduced to half compared to the configuration shown in Fig. 7. This reduces conduction loss when current flows, and also reduces the number of parts. This effect becomes greater as the number of branch points increases.

[0051] Furthermore, by using the three-way circuit breaker 300 according to this embodiment, it becomes possible to protect against a short circuit (internal short circuit) that occurs at a branch point inside the three-way circuit breaker 300. Furthermore, the configuration according to this embodiment makes it possible to limit the current output from each consumer.

[0052] (Regarding Determination Conditions) Here, a determination condition for a "detection error" and a determination condition for an "internal short circuit" will be described as examples of determination conditions for determination performed by the control device 100 in the three-way circuit breaker 300. Here, reference will be made to FIGS. 9 and 10 .

[0053] As shown in FIGS. 9 and 10, in the three-way circuit breaker 300, the current flowing from the branch point to the left side of the main line is represented by I （ａ） Let I be the current flowing from the branch point to the right side of the main line. （ｂ） The current flowing downward from the branch point is I （ｃ） These currents are assumed to be positive in the outward direction (the direction of the arrows in FIG. 9).

[0054] The calculation unit 120 calculates "I （ａ） +I （ｂ） +I （ｃ） If the calculation result is "=0", it is determined that the power supply system is in a normal state.

[0055] "I （ａ） +I （ｂ） +I （ｃ） 9, the abnormal state is determined as abnormal state 1. Abnormal state 1 will be described with reference to FIG.

[0056] As described above, abnormal state 1 occurs when the sum of the current inflow and outflow is greater than 0. That is, abnormal state 1 occurs when, for example, all three measurement units 200 shown in Fig. 9 measure currents flowing outward. Since this is an impossible state, an alarm (detection error) is output from the communication unit 110, for example.

[0057] "I （ａ） +I （ｂ） +I （ｃ）<0" is defined as abnormal state 2. Abnormal state 2 will be described with reference to FIG.

[0058] As described above, abnormal state 2 occurs when the sum of the current inflow and outflow is less than zero. That is, abnormal state 2 occurs when, for example, all three measurement units 200 shown in FIG. 10 measure an inward current. In this case, it is determined that an internal short circuit has occurred. Therefore, the communication unit 110 outputs an alarm (internal short circuit), and the control unit 130 cuts off the current in all breaker units.

[0059] (Detailed Configuration Example of Three-Way Circuit Breaker 300) Next, a more detailed configuration example of the three-way circuit breaker 300 will be described with reference to Fig. 11. Fig. 11 is a diagram showing an example of the internal circuit of the three-way circuit breaker 300. In Fig. 11, the circuit breakers are marked with the symbols (a), (b), and (c) for the purpose of explaining examples of setting values, which will be described later.

[0060] 11 shows an example in which the three-way circuit breaker 300 is realized using semiconductor elements (e.g., MOSFETs), but this is just one example. The three-way circuit breaker 300 can also be realized using functional units other than semiconductor elements. For example, the three-way circuit breaker 300 can be realized by combining a relay or an electromagnetic contactor with a current detection unit. For example, a Hall element or a shunt resistor can be used as the current detection unit.

[0061] Furthermore, the communication line may be, for example, a metal wire, an optical cable, or Wi-Fi (registered trademark).

[0062] As shown in FIG. 11 , the three-way circuit breaker 300 includes a circuit breaker unit 10 (a), a circuit breaker unit 20 (b), a circuit breaker unit 30 (c), a control device 100 , and a measurement unit 200 .

[0063] The interrupter 10(a) is connected to a main line extending in the (a) direction, the interrupter 20(b) is connected to a main line extending in the (b) direction, and the interrupter 30(c) is connected to a branch line extending in the (c) direction.

[0064] Each cutoff unit includes a semiconductor element (e.g., MOSFET), a capacitor, and a diode. Each of A to F in Fig. 11 contains a capacitor or a diode. Specifically, for example, A, D, and F contain diodes, and B, C, and E contain capacitors. The three parts shown as B, C, and E may be unified into one part.

[0065] 11, the measurement unit 200 includes a plurality of current sensors. Each current sensor measures the current flowing through the positive and negative poles, and the current value is measured by the measurement unit 200. The measurement unit 200 may be provided outside the interrupter unit.

[0066] The control device 100 has a communication unit 110, a calculation unit 120, and a control unit 130. The calculation unit 120 determines the setting value of each breaker unit based on the direction of the current corresponding to the current value output from the measurement unit 200. The calculation unit 120 also compares the current value with the setting value, and sends a signal to the control unit 130 when the current value is greater than the setting value.

[0067] The control unit 130 controls the ON / OFF of each cutoff unit based on the calculation result of the calculation unit 120 .

[0068] Fig. 12 shows an example of the setting value of each breaker unit determined by the calculation unit 120. As shown in Fig. 12, for example, if the direction of the current in breaker unit 10(A) is direction (a), the calculation unit 120 determines the setting value of breaker unit 10(A) to be 30A.

[0069] In the example of Figure 12, when current flows in the (a) direction in the interrupter unit 10 (a), the circuit of the interrupter unit 10 is opened (the current is interrupted) when the current value is 30 A or more. When current flows in the (b) direction in the interrupter unit 20 (b), the circuit of the interrupter unit 20 is opened when the current value is 10 A or more. When current flows in the (c) direction in the interrupter unit 30 (c), the circuit of the interrupter unit 30 is opened when the current value is 30 A or more.

[0070] In this embodiment, the three-way circuit breaker 300 is a single package formed by combining (linking) three one-way circuit breaking units 10, 20, and 30. However, the three-way circuit breaker 300 is not limited to being configured as a single package.

[0071] (Processing Flow) The processing flow of the three-way circuit breaker 300 will be described with reference to the flowchart of FIG.

[0072] <S101> In S101, basic data is input to the three-way circuit breaker 300 (specifically, the control device 100). Specifically, for example, the following basic data (1) and (2) are input.

[0073] ) + (setting value of main line circuit breaker 20 (right))} / 2 English: (1) Setting values ​​for the three-way circuit breaker 300 Setting value 1: setting value when current flows in direction (a) Setting value 2: setting value when current flows in direction (b) Setting value 3: setting value when current flows in direction (c) (2) Setting values ​​for overcurrent protection sent to the bidirectional DC / DC converter Setting value 1: setting value for current toward the branch line side Setting value 2: setting value for current toward the customer's premises Specifically, the setting value 1 above is set to a value within the range of the following condition, for example: "Setting value 1 < {(setting value of main line circuit breaker 10 (left)) + (setting value of main line circuit breaker 20 (right))} / 2" The setting value 2 above is set to a value within the range of the following condition: "Setting value 2 < setting value of the branch line circuit breaker" <S102> In S102, the control device 100 (for example, the communication unit 110) communicates with the bidirectional DC / DC converter to acquire information about the bidirectional DC / DC converter. Specifically, the control device 100 acquires status parameters (normal or abnormal), measurement data (current, voltage), setting values ​​(overcurrent threshold, etc.) for the bidirectional DC / DC converter. Based on the acquired information, the control device 100 also confirms that there is no abnormality in the bidirectional DC / DC converter.

[0074] <S103> In S103, the control device 100 changes the settings of the bidirectional DC / DC converter. Specifically, the control device 100 transmits and sets the overcurrent protection (OCP) current values ​​(setting value 1 and setting value 2) to the bidirectional DC / DC converter.

[0075] <S104> In S104, the measurement unit 200 performs current measurement. Specifically, the measurement unit 200 measures the direction and magnitude of the current passing through each interrupter.

[0076] <S105, S106> In S105, if the calculation unit 120 determines that "the value of the current flowing in the (a) direction is greater than the set value 1," the control unit 130 opens the breaker unit 10(A) in S106. In addition, for example, the communication unit 110 outputs an alarm.

[0077] <S107, S108> If the calculation unit 120 determines in S107 that "the value of the current flowing in the (b) direction is greater than the set value 2," the control unit 130 opens the breaker unit 20(b) in S108. In addition, for example, the communication unit 110 outputs an alarm.

[0078] <S109, S110> In S109, if the calculation unit 120 determines that "the value of the current flowing in the (c) direction is greater than the set value 3," the control unit 130 opens the breaker unit 30(c) in S110. In addition, for example, the communication unit 110 outputs an alarm.

[0079] <S111, S112> In S111, the calculation unit 120 calculates "I （ａ） +I （ｂ） +I （ｃ） If it is determined that the value is ".gtoreq.0", then in step S112, the communication unit 110, for example, outputs an alarm (detection error).

[0080] <S113, S114> In S113, the calculation unit 120 calculates "I （ａ） +I （ｂ） +I （ｃ） If it is determined that the value is "<0", the control unit 130 opens all the interrupters in S114. Also, for example, the communication unit 110 outputs an alarm.

[0081] (Basic Operation Example) A basic operation example when the three-way circuit breaker 300 is used in a power supply system will be described with reference to FIGS.

[0082] 14 to 16, there are two customers, Building A and Building B, with three-way circuit breaker 300A connected to Building A and three-way circuit breaker 300B connected to Building B. In addition, in each of the three-way circuit breakers 300 in Figures 14 to 16, the short-circuit point is shown, and the setting value (here, the threshold value of the current value) that coincides with the direction of the current is surrounded by a thick frame.

[0083] 14, a short circuit occurs on the right side of the three-way circuit breaker 300B, causing a short-circuit current to flow to the right. In this case, of the circuit breaker units 20 and 50, which have rightward setting values, the circuit breaker unit 50 with the smaller setting value (the one closer to the short-circuit point) operates first.

[0084] 15, a short circuit occurs on the left side of the three-way circuit breaker 300A, causing the short-circuit current to flow to the left. In this case, of the circuit breaker units 10 and 40, which have leftward setting values, the circuit breaker unit 10 with the smaller setting value (the one closer to the short-circuit point) operates first.

[0085] 16, a short circuit occurs on the branch side of three-way circuit breaker 300B, and short-circuit current flows in the direction of Building B. In this case, of circuit breaker unit 20 and circuit breaker unit 60, which have setting values ​​for the direction of current flow, the circuit breaker unit 60 with the smaller setting value (the one closer to the short-circuit point) operates first.

[0086] (Example of Flow from Measurement to Control) Here, a specific example of the flow from measurement to control in the three-way circuit breaker 300 will be described with reference to FIG.

[0087] In S1000, the measurement unit 200 measures the current in each interrupter unit. In S2000, the calculation unit 120 determines whether or not "the set interruption threshold value<the actual current value" in each interrupter unit.

[0088] If the "set cutoff threshold value<actual current value" for a certain cutoff unit, in S3000, the control unit 130 applies a voltage to the gate of the semiconductor element of that cutoff unit. In S4000, the application of the voltage to the gate activates the semiconductor element, thereby cutting off the current.

[0089] (Example 1 of Power Supply System) As Example 1 of the power supply system, Fig. 18 shows an example of a loop wiring type power supply system in which a three-way circuit breaker 300 according to this embodiment is inserted. In the example shown in Fig. 18, three-way circuit breakers 300-1 to 300-4 are provided on a main line, which is a loop wiring. As described above, each three-way circuit breaker 300 has a configuration including three one-way interrupting units. Each three-way circuit breaker 300 is connected to a consumer via a branch line.

[0090] (Power Supply System Example 2) As power supply system example 2, Fig. 19 shows an example of a bus-wiring type power supply system in which a three-way circuit breaker 300 according to this embodiment is inserted. In the example shown in Fig. 19, three-way circuit breakers 300-1 to 300-4 are provided on a trunk line, which is a bus wiring. As described above, each three-way circuit breaker 300 has a configuration including three one-way circuit breakers. Each three-way circuit breaker is connected to a consumer via a branch line.

[0091] (Variant) In the example described so far (referred to as the basic example), three of the three-way circuit breakers 300 are equipped with one-way circuit breakers as circuit breakers, and the output current from the consumer is limited by linking a bidirectional DC / DC converter installed at the consumer with a downward one-way circuit breaker 30 installed on the branch line.

[0092] However, there are cases where the bidirectional DC / DC converter cannot be linked to the downward-facing unidirectional cutoff unit 30 installed on the branch line. In such cases, the bidirectional cutoff unit 30 may be used instead of the downward-facing unidirectional cutoff unit 30.

[0093] That is, in the modified example, of the three cutoff units, the cutoff unit 30 connected to the branch line is a bidirectional cutoff unit 30, and the other two cutoff units are unidirectional cutoff units.

[0094] An example of the configuration of a three-way circuit breaker 300 in this case is shown in Fig. 20. Here, differences from the three-way circuit breaker 300 in the basic example shown in Fig. 6 will be mainly described.

[0095] As shown in Fig. 20, a bidirectional interrupting unit 30 is used as the interrupting unit 30 in a modified three-way circuit breaker 300. The bidirectional interrupting unit 30 is a bidirectional interrupting unit including two semiconductor elements (e.g., MOSFETs) as shown in Fig. 5. However, the bidirectional interrupting unit may also be comprised of two unidirectional interrupting units, one facing downward and the other facing upward, installed on the branch line.

[0096] As shown in FIG. 20, in this modification, signal lines (measurement lines, control lines, communication lines) between the bidirectional DC / DC converter installed at the customer's facility and the three-way circuit breaker 300 are not required.

[0097] The number of semiconductor elements on the branch lines in the modified example is greater than in the basic example. However, increasing the number of semiconductor elements on the branch lines does not have much effect on the decrease in efficiency. The reason for this is as follows.

[0098] In this modification, the number of semiconductor elements on the current path is two on the branch line and 2×n on the main line (where n is the number of branch points). If the configuration shown in FIG. 7 were adopted, the number of semiconductor elements on the main line would be 4×n.

[0099] For this reason, it is more effective for the system as a whole to reduce the number of semiconductor devices on the trunk line than on the branch lines. This point will be explained with reference to FIG.

[0100] For example, when a current flows from consumer A to consumer C, the current passes through two breakers on the branch line and four breakers on the main line.

[0101] That is, the more three-way circuit breakers 300 installed in the loop wiring (main line), the more circuit breakers there are on the main line, but the number of circuit breakers on the branch line remains at 2. Therefore, even if two-way circuit breakers are used as the two circuit breakers on the branch line, there is little impact on the reduction in efficiency of the system as a whole.

[0102] (Operation Example 1 in Modification) As described above, a first operation example relating to a bidirectional cutoff unit when the bidirectional cutoff unit is used as the cutoff unit on the branch line will be described with reference to FIG. 22 .

[0103] In operation example 1 of the modified example, as shown in Fig. 22 , there are consumer A and consumer B connected by a power line, and bidirectional interrupter 30-1 and bidirectional interrupter 30-2 are located between consumer A and consumer B. Fig. 22(a) shows a case where current due to a short circuit flows in a direction from consumer A to consumer B (referred to as direction (a)), and Fig. 22(b) shows a case where current due to a short circuit flows in a direction from consumer B to consumer A (referred to as direction (b)).

[0104] 22, for the bidirectional cutoff unit 30-1, a setting value for direction (a) is set to 12A and a setting value for direction (b) is set to 6A. For the bidirectional cutoff unit 30-2, a setting value for direction (a) is set to 6A and a setting value for direction (b) is set to 12A.

[0105] 22(a), a short circuit occurs on the side of consumer B, causing a large current to flow in direction (a). Bidirectional circuit breaker 30-2, which has a smaller set value corresponding to direction (a), operates before bidirectional circuit breaker 30-1, and can therefore quickly interrupt the current on the side closer to the short circuit point.

[0106] 22(b), a short circuit occurs on the customer (a) side, generating a large current in direction (b). Bidirectional circuit breaker 30-1, which has a smaller set value corresponding to direction (b), operates before bidirectional circuit breaker 30-2, and can therefore quickly interrupt the current on the side closest to the short circuit point.

[0107] (Operation Example 2 in Modification) Next, operation example 2 in the modification will be described with reference to Fig. 23. In operation example 2, as shown in Fig. 23, there are consumer A and consumer B connected by a power line, and between consumer A and consumer B there are bidirectional interrupter 30-1, unidirectional interrupters 10 and 20(1) (two unidirectional interrupters), unidirectional interrupters 10 and 20(2) (two unidirectional interrupters), and bidirectional interrupter 30-2.

[0108] Figure 23(a) shows a case where current due to a short circuit flows in a direction from consumer A to consumer B (direction (a)), and Figure 23(b) shows a case where current due to a short circuit flows in a direction from consumer B to consumer A (direction (b)).

[0109] As shown in FIG. 23, the setting of the set values ​​for the bidirectional cutoff unit 30-1 and the bidirectional cutoff unit 30-2 is the same as in the case of the operation example 1 (FIG. 22).

[0110] For the "one-way interrupter 10, 20(1)," a setting value for direction (a) is set to 10A, and a setting value for direction (b) is set to 8A. Also, for the "one-way interrupter 10, 20(2)," a setting value for direction (a) is set to 8A, and a setting value for direction (b) is set to 10A.

[0111] 23(a), a short circuit occurs on the side of consumer B, causing a large current to flow in the direction (a). The bidirectional circuit breaker 30-2, which has the smallest set value corresponding to the direction (a), operates before the other circuit breakers, and can therefore quickly interrupt the current on the side closest to the short circuit point.

[0112] 23(b), a short circuit occurs on the side of consumer A, causing a large current to flow in direction (b). Bidirectional circuit breaker 30-1, which has the smallest set value corresponding to direction (b), operates before the other circuit breakers, and can therefore quickly interrupt the current on the side closest to the short circuit point.

[0113] As explained using Figures 22 and 23, by appropriately setting a plurality of setting values ​​in a plurality of circuit breakers, it is possible to create a larger number of protection coordination sections.

[0114] (Example 1: Specific Example of Power Supply System) Next, a more specific example of a power supply system will be described as Example 1. Fig. 24 shows an example of an outdoor DC power supply system that incorporates a three-way circuit breaker 300 according to this embodiment. The three-way circuit breaker 300 of the example shown in Fig. 24 includes three one-way circuit breakers.

[0115] This outdoor DC power supply system includes consumers A to C, each equipped with a device including a bidirectional DC / DC converter. In this example, each consumer is connected to a three-way circuit breaker 300 by bus wiring.

[0116] (Example 2) Next, Example 2 will be described with reference to Figures 25 and 26. Example 2 is an example in which the set value is a current threshold value.

[0117] As shown in Fig. 25, in Example 2, three-way circuit breakers 300-1 to 300-4 are provided on the trunk line of the loop wiring, and customers are connected to each of the three-way circuit breakers 300 as shown in Fig. 27. Each of the three circuit breakers in each three-way circuit breaker 300 is a one-way circuit breaker.

[0118] The diagram shows the current direction and the current value as the setting value of each circuit breaker when the current flows in that direction. However, since it is not possible to set an upward setting value (current transmitted from the consumer) for the unidirectional circuit breaker 30 on the branch line to which the consumer is connected, coordination is achieved by setting the setting value using the overcurrent protection (OCP) function of the bidirectional DC / DC converter of the connected consumer.

[0119] Suppose the current flow changes from Fig. 25 to Fig. 26. That is, in the situation shown in Fig. 26, current flows from consumer A to consumer C and consumer D, respectively, and current flows from consumer B to consumer C and consumer D, respectively. In the case of the current flow shown in Fig. 26, the set values ​​are as shown.

[0120] That is, in the second embodiment, the setting value of the one-way circuit breaking unit 30 is 30 A when a current flows toward a consumer, and 40 A when a current flows from a consumer toward the bus (main line). The setting value of each of the one-way circuit breaking units 10 and 20 is 35 A.

[0121] Third Embodiment Next, a third embodiment will be described with reference to Fig. 27 and Fig. 28. The third embodiment is an example in which the setpoint is a delay time.

[0122] As shown in Fig. 27, in Example 3, three-way circuit breakers 300-1 to 300-4 are provided on the trunk line of the loop wiring, and customers are connected to each of the three-way circuit breakers 300 as shown in Fig. 27. Each of the three circuit breakers in each three-way circuit breaker 300 is a one-way circuit breaker.

[0123] The diagram shows the current direction and the delay time set by each breaker when current flows in that direction. However, since the unidirectional breaker 30 on the branch line to which the customer is connected cannot set a set value for the upward current, coordination is achieved by setting a set value using the overcurrent protection (OCP) function of the connected customer's bidirectional DC / DC converter.

[0124] Suppose the current flow changes from Fig. 27 to Fig. 28. That is, in the situation shown in Fig. 28, current flows from consumer A to consumer C and consumer D, respectively, and current flows from consumer B to consumer C and consumer D, respectively. In the case of the current flow shown in Fig. 28, the set values ​​are as shown.

[0125] That is, in the third embodiment, the one-way circuit breaking unit 30 uses a set value of 0 s when a current flows toward a consumer, and uses a set value of +2 ms when a current flows from a consumer to the main line. The one-way circuit breaking units 10 and 20 use a set value of +1 ms in both directions.

[0126] (Hardware Configuration Example) Any of the control devices 100 described in this embodiment can be realized, for example, by causing a computer to execute a program. This computer may be a physical computer or a virtual machine on the cloud.

[0127] That is, the control device 100 can be realized by using hardware resources such as a CPU and memory built into a computer to execute a program corresponding to the processing performed by the control device 100. The program can be recorded on a computer-readable recording medium (such as a portable memory) and can be saved or distributed. The program can also be provided via a network such as the Internet or email.

[0128] Fig. 29 is a diagram showing an example of the hardware configuration of the computer. The computer in Fig. 29 includes a drive device 1000, an auxiliary storage device 1002, a memory device 1003, a CPU 1004, an interface device 1005, a display device 1006, an input device 1007, an output device 1008, and the like, all of which are interconnected by a bus BS. The computer may further include a GPU.

[0129] The program that realizes the processing on the computer is provided by a recording medium 1001, such as a CD-ROM or a memory card. When the recording medium 1001 storing the program is set in the drive device 1000, the program is installed from the recording medium 1001 to the auxiliary storage device 1002 via the drive device 1000. However, the program does not necessarily have to be installed from the recording medium 1001, but may be downloaded from another computer via a network. The auxiliary storage device 1002 stores the installed program as well as necessary files, data, etc.

[0130] The memory device 1003 reads and stores the program from the auxiliary storage device 1002 when an instruction to start the program is received. The CPU 1004 realizes functions related to the control device 100 in accordance with the program stored in the memory device 1003. The interface device 1005 is used as an interface for connecting to a network, etc. The display device 1006 displays a GUI (Graphical User Interface) or the like according to the program. The input device 1007 is composed of a keyboard, mouse, buttons, a touch panel, etc., and is used to input various operation instructions. The output device 1008 outputs the results of calculations.

[0131] As described above, the technology described in the present embodiment enables appropriate protection and coordination in a power supply system. Also, the number of semiconductor devices arranged on the trunk line in the power supply system can be reduced.

[0132] The following additional notes are provided regarding the above-described embodiments.

[0133] <Additional Notes> (Additional Item 1) A device comprising: a first unidirectional interrupter arranged on a first direction side of a power line; a second unidirectional interrupter arranged on a second direction side of the power line; and a third unidirectional interrupter arranged on a side of a branch line extending from a branch point of the power line. (Additional Item 2) The device according to Additional Item 1, wherein the first unidirectional interrupter, the second unidirectional interrupter, and the third unidirectional interrupter each comprise one semiconductor element that performs interruption operation. (Additional Item 3) The device according to Additional Item 1 or 2, wherein the device determines that an internal short circuit has occurred when it detects that the sum of the value of the current flowing through the first unidirectional interrupter, the value of the current flowing through the second unidirectional interrupter, and the value of the current flowing through the third unidirectional interrupter has become a negative value, when the direction of current flowing toward the outside of the device is defined as the positive direction. (Supplementary Item 4) The device according to any one of Supplementary Items 1 to 3, wherein the device determines that an error has occurred when it detects that the sum of the value of the current flowing in the first unidirectional interrupter, the value of the current flowing in the second unidirectional interrupter, and the value of the current flowing in the third unidirectional interrupter has become a positive value, when the direction of current flowing toward the outside of the device is defined as a positive direction. (Supplementary Item 5) The device according to any one of Supplementary Items 1 to 4, wherein the device interrupts the current flowing in the third unidirectional interrupter when it determines that the value of the current flowing toward a customer connected to the branch line has reached a threshold. (Supplementary Item 6) The device according to any one of Supplementary Items 1 to 5, wherein the device communicates with a bidirectional DC / DC converter in a customer connected to the branch line, and controls the overcurrent protection threshold of the bidirectional DC / DC converter.

[0134] Although the present embodiment has been described above, the present invention is not limited to such a specific embodiment, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims.

[0135] 10 to 60 Breaker unit 100 Control device 110 Communication unit 120 Calculation unit 130 Control unit 200 Measurement unit 300 Three-way circuit breaker 301 Power input / output terminal 302 Communication input / output terminal 1000 Drive device 1001 Recording medium 1002 Auxiliary storage device 1003 Memory device 1004 CPU 1005 Interface device 1006 Display device 1007 Input device 1008 Output device

Claims

1. An apparatus comprising: a first unidirectional blocking portion disposed on a side of a power line in a first direction; a second unidirectional blocking portion disposed on a side of the power line in a second direction; and a third unidirectional blocking portion disposed on a side of a branch line extending from a branch point in the power line.

2. The apparatus according to claim 1, wherein each of the first unidirectional blocking portion, the second unidirectional blocking portion, and the third unidirectional blocking portion includes one semiconductor element that performs a blocking operation.

3. When the direction of the current flowing toward the outside of the apparatus is defined as the positive direction, the apparatus determines that an internal short circuit has occurred when it detects that the sum of the value of the current flowing through the first unidirectional blocking portion, the value of the current flowing through the second unidirectional blocking portion, and the value of the current flowing through the third unidirectional blocking portion becomes a negative value. The apparatus according to claim 1.

4. When the direction of the current flowing toward the outside of the apparatus is defined as the positive direction, the apparatus determines that an error has occurred when it detects that the sum of the value of the current flowing through the first unidirectional blocking portion, the value of the current flowing through the second unidirectional blocking portion, and the value of the current flowing through the third unidirectional blocking portion becomes a positive value. The apparatus according to claim 1.

5. When the apparatus determines that the value of the current in the direction toward the consumer connected to the branch line has reached a threshold value in the third unidirectional blocking portion, the apparatus blocks the current flowing through the third unidirectional blocking portion. The apparatus according to claim 1.

6. The apparatus according to claim 1, wherein the apparatus communicates with a bidirectional DC / DC converter in a consumer connected to the branch line and controls a threshold value of overcurrent protection of the bidirectional DC / DC converter.

Images