DC power distribution system, control device, operation state determination method, and program

Abstract

Provided is a DC power distribution system for distributing power from a power source device to a load device via a power distribution network. The DC power distribution system comprises a measurement device provided to the power distribution network, and a control device having a determination unit that acquires a voltage value and a current value measured by the measurement device and determines the operation state of the DC power distribution system on the basis of a waveform indicating changes in the voltage value and a waveform indicating changes in the current value.

Description

[Technical field]

[0001] The present invention relates to a technique for detecting faults, such as ground faults and short circuits, that occur in a power distribution system. [Background technology]

[0002] 2. Description of the Related Art In a power distribution system, when an accident such as a ground fault or a short circuit is detected, it is necessary to take measures such as stopping the power distribution from a power supply device.

[0003] As an example of a device for detecting faults such as ground faults and short circuits, a distance relay (e.g., the motor relay described in Non-Patent Document 1) is used at the sending end of an AC substation. A distance relay receives voltage and current as input quantities, and operates when the function of the ratio of voltage to current falls below a predetermined value. This ratio is called the impedance seen by the relay.

[0004] Meanwhile, in communication buildings, data centers, etc., high-voltage DC power distribution systems are being introduced to reduce power loss in the entire system and to save energy. In high-voltage DC power distribution systems, power is distributed at a high voltage, for example, 380V. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] Terminology Explanation (22nd Theme: Mohm Relay), IEEJ Transactions on Power and Energy, Vol. 132 (2012) No. 8, https: / / www.jstage.jst.go.jp / article / ieejpes / 132 / 8 / 132_NL8_6 / _pdf Summary of the Invention [Problem to be solved by the invention]

[0006] Since the DC used in a high-voltage DC distribution system has no reactance, it is not possible to use a distance relay such as the Morse relay described in Non-Patent Document 1. In addition, there are no distance relays on the market for high-voltage DC distribution such as 380V.

[0007] Conventional technologies exist for detecting faults such as ground faults and short circuits that occur in DC power distribution systems, but the detection accuracy is insufficient, and such technologies can erroneously detect events that are not accidents as accidents.

[0008] An object of the present invention is to provide a technique that enables accurate detection of an accident that occurs in a DC power distribution system. [Means for solving the problem]

[0009] According to the disclosed technique, there is provided a DC power distribution system that distributes power from a power supply device to a load device via a power distribution network, comprising: A meter provided in the power distribution network; a control device including a determination unit that acquires voltage values ​​and current values ​​measured by the measuring instruments and determines an operating state of the DC power distribution system based on a waveform indicating a change in the voltage value and a waveform indicating a change in the current value; The operating state is a ground fault, a short circuit, a partial short circuit, an inrush current, a load connection, a load ON / load OFF, or a load change; The determination unit determines whether a partial short circuit has occurred or whether a load has been connected or turned on based on a waveform indicating a change in current value and device information obtained from the load device. A DC power distribution system is provided. Effect of the Invention

[0010] According to the disclosed technology, it is possible to accurately detect an accident that occurs in a DC power distribution system. [Brief description of the drawings]

[0011] [Figure 1] 1 is a diagram showing a first example of a configuration of a DC fault detection system according to an embodiment of the present invention; [Diagram 2]11A and 11B are diagrams illustrating examples of detection values ​​and determination results. [Diagram 3] FIG. 2 is a diagram showing a second configuration example of a DC fault detection system according to an embodiment of the present invention. [Figure 4] FIG. 2 is a diagram illustrating an example of the configuration of a control device. [Diagram 5] FIG. 2 is a diagram illustrating an example of the configuration of a control device. [Figure 6] FIG. 2 illustrates an example of the configuration of a learning device. [Figure 7] FIG. 2 illustrates an example of a hardware configuration of the apparatus. [Figure 8] 1 is a flowchart illustrating an operation of the control device. [Figure 9] 1 is a flowchart illustrating an operation of the control device. [Figure 10] FIG. 13 is a diagram showing an example of a waveform. [Figure 11] FIG. 13 is a diagram showing an example of a waveform. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention (the present embodiment) 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 DC power distribution system in this embodiment is assumed to be a high-voltage DC power distribution system (hereinafter referred to as a DC power distribution system) that distributes power at 380 V DC. However, "380 V" is just an example. The present invention is not limited to high-voltage DC power distribution systems, but is applicable to DC power distribution systems in general.

[0014] (System configuration example 1) 1 shows a configuration example 1 of a DC power distribution system according to the present embodiment. Configuration example 1 is a system that distributes DC power from site A to site B. Site A and site B are buildings such as communication buildings, but are not limited to buildings.

[0015] In configuration example 1, site A is provided with converter A20, and site B is provided with converter B30. Each converter is a DC / DC converter, which is a device that converts the magnitude of a direct current voltage. Converter A20 may be an AC / DC converter. As shown in the figure, each converter has a voltage conversion unit, an insulating function, and a gate blocking function.

[0016] Converter A20 at site A and converter B30 at site B are connected by a power distribution network (positive and negative power distribution lines), and 380V DC current is distributed from converter A20 at site A to converter B30 at site B. Converter B30 is an example of a load device that receives the distributed power. At site B, one or more load devices (servers, etc.) are connected under converter B30. The "load devices" include converter B30 and devices such as servers that are powered by converter B30. The "DC power distribution system" includes converter A20, the power distribution network, and the load devices.

[0017] Converter A20 is an example of a power supply device that can supply sufficient current to an accident point (e.g., ground fault, short circuit, partial short circuit, etc.) in a power distribution network (including a power network in a load device receiving power).

[0018] Furthermore, a control device 100A is provided at the site A, and a control device 100B is provided at the site B. The control device 100A and the control device 100B are connected via a communication network.

[0019] The control device 100A may be a device inside the converter A20, or may be a device outside the converter A20. The control device 100A may also be provided outside the site A. The control device 100B may be a device inside the converter B30, or may be a device outside the converter B30. The control device 100B may also be provided outside the site B. Instead of providing a control device for each site, one control device may be provided for multiple sites.

[0020] As shown in Fig. 1, a learning device 200 is provided. The learning device 200 may be installed anywhere; for example, a virtual machine on the cloud may be used as the learning device 200. The learning device 200 is connected to the control device 100A and the control device 100B via a communication network. Note that the control device 100A or the control device 100B may function as the learning device 200.

[0021] In the DC power distribution system of this embodiment, a neutral grounding configuration using a high resistance is used at site A. Specifically, as shown in Fig. 1, resistors 1 and 2 are provided between the output portion of converter A20 and the power distribution end (the boundary portion between the inside and outside of site A) between the positive side distribution line and the negative side distribution line, and the neutral point therebetween is grounded to the earth (earth). Both resistors 1 and 2 have high resistance of, for example, about several MΩ. The neutral grounding configuration using a high resistance may be provided inside converter A20.

[0022] As shown in Figure 1, at site A, a voltmeter 3 is provided between the positive distribution line (+) and the neutral point, a voltmeter 4 is provided between the negative distribution line (-) and the neutral point, and an ammeter 5 is provided between the neutral point and the ground point.

[0023] Ammeters 6 and 7 are provided on the negative and positive distribution lines, respectively. A zero-phase current transformer (ZCT) 8 is also provided. When an imbalance occurs between the round-trip currents in the positive and negative distribution lines, the zero-phase current transformer 8 measures and outputs the current value that occurs due to the imbalance.

[0024] Also, at site B, between the receiving end (the boundary between the outside and inside of site B) and converter B30, a voltmeter 9 is provided between the positive distribution line and the negative distribution line, and an ammeter 10 is provided on the positive distribution line.

[0025] The method of arranging measuring instruments such as ammeters and voltmeters shown in Fig. 1 is one example. More or fewer measuring instruments may be arranged than in the arrangement method shown in Fig. 1. For example, no measuring instruments may be arranged on the site B side.

[0026] (Operation overview) At site A, each measuring instrument performs measurement at short time intervals (e.g., on the order of a few us to a few ms), and control device 100A acquires the measurement results obtained by each measuring instrument. Similarly, at site B, each measuring instrument performs measurement at short time intervals (e.g., on the order of a few us to a few ms), and control device 100B acquires the measurement results obtained by each measuring instrument.

[0027] Both the control device 100A and the control device 100B are capable of determining the operating state (accidents and events other than accidents such as load fluctuations) in the DC power distribution system, but in this embodiment, the determination is performed by the control device 100A.

[0028] When the control device 100A determines the operating state, the control device 100B transmits the measurement results obtained by each measuring device at site B to the control device 100A via the communication network. The control device 100B also monitors the state of the load devices at short intervals (for example, measurements in units of several us to several ms), and transmits information (equipment information) on the state of the load devices obtained by monitoring to the control device.

[0029] Based on the measurement results and equipment information obtained at sites A and B, the control device 100A determines the operating status, such as ground fault (positive side), ground fault (negative side), short circuit, partial short circuit, inrush current, load connection, load ON / load OFF, load fluctuation, etc., from one or more (including all) of the voltage value, current value, waveform indicating change in voltage value, waveform indicating change in current value, and equipment information, etc.

[0030] Note that a short circuit means that the positive and negative distribution lines are connected with a small resistance, and a partial short circuit means that the positive and negative distribution lines are connected with a large resistance.

[0031] The control device 100A displays the determination result. The control device 100A transmits the determination result to the control device 100B, so that the control device B can also display the determination result.

[0032] Furthermore, when the control device 100A detects an accident such as a ground fault or a short circuit, it can operate the gate block in the converter A20 and stop the power distribution by transmitting an abnormality signal to the converter A20. Furthermore, when the control device 100A detects an accident such as a ground fault or a short circuit, it can transmit a determination result or an abnormality signal to the control device 100B, which can cause the control signal 100B to operate the gate block or the like at the site B.

[0033] Furthermore, the control device 100A can distinguish events such as inrush current and load connection that are not accidents from waveforms that indicate changes in current or voltage values, and can prevent malfunctions such as erroneous stop of power distribution.

[0034] <Example of judgment result> Figure 2 shows an example of the values ​​detected by the measuring instruments and the judgment results. V1 in Figure 2 represents the value detected by the voltmeter 3 between the neutral point and the positive distribution line, and V2 represents the value detected by the voltmeter 4 between the neutral point and the negative distribution line. A is, for example, the value (current value) detected by the ammeter 7 or ammeter 6. "Peak" means the maximum value (the maximum value among values ​​that fluctuate in a short period of time).

[0035] dV1 / dt is the derivative of V1 with respect to time t and represents the change in V1 over time. The same is true for dV2 / dt and dA / dt. ∫(dA / dt)dt represents the integral of the change in A.

[0036] In (V1+V2) / I, I is, for example, the detection value (current value) of ammeter 7 or ammeter 6. Impedance Z (which may be called "resistance" when only DC is considered) is obtained from (V1+V2) / I.

[0037] For example, when an accident such as a short circuit occurs in the power distribution network between base A and base B, the control device 100A can calculate the impedance of the power distribution line between base A (specifically, a measuring instrument) and the accident point by (V1+V2) / I, and can calculate the distance between base A and the accident point. In other words, the distance can be calculated by dividing the impedance obtained by (V1+V2) / I by the impedance per unit length of the power distribution line between base A and the accident point.

[0038] The impedance per unit length of the power distribution line is determined by the thickness (cross-sectional area) of the power distribution line. Generally, the thickness of the power distribution line (i.e., the impedance per unit length of the power distribution line) is determined by the scale of the power distribution network (power distribution between bases, power distribution within a base, etc.), so the control device 100A stores the impedance per unit length of the power distribution line for each scale of the power distribution network in advance in a storage unit, and calculates the distance using the impedance per unit length that matches the scale of the power distribution network to be controlled. The control device 100A may also derive the impedance including the jX (reactance) component when a transient phenomenon of the current or voltage is captured.

[0039] In Fig. 2, for example, when a measurement result corresponding to a voltage waveform in which V1 suddenly becomes 0 and V2 suddenly becomes 380 V is obtained, it is possible to determine that a ground fault has occurred in the positive distribution line. Other events are also as shown in Fig. 2. A more specific determination logic (flow) will be described later.

[0040] The control device 100A and the control device 100B each transmit the acquired measurement results, etc. to the learning device 200, and the learning device 200 may learn the relationship between the waveforms and events from either or both of the voltage value waveform and the current value waveform.

[0041] The learning method is not limited to a specific method, and for example, a neural network model may be used. As an example, learning about inrush current will be described. First, a large number of waveforms obtained from the measurement results of an ammeter when an inrush current occurs in a power distribution network are obtained as learning data.

[0042] The learning device 200 inputs the waveform of the learning data into the model, and learns the parameters of the model so that the waveform is classified as an "inrush current." The learned model is then stored in the control device 100A. By using the model, the control device 100A can determine whether or not the waveform of the measurement result corresponds to an inrush current.

[0043] In the same way, the model can be used to distinguish between events such as a ground fault (positive side), a ground fault (negative side), a short circuit, a partial short circuit, a load connection, a load ON (load application) / OFF, and a load change.

[0044] Using a neural network model as described above to distinguish an event (operating state) is one example.

[0045] For example, for each event, a representative waveform observed when the event occurs is prepared as a representative waveform and stored in a storage unit of the control device 100A. The control device 100A can compare the detected waveform with the representative waveform of each event and determine that an event with a representative waveform similar to the detected waveform has occurred. In comparing the detected waveform with the representative waveform of each event, for example, any one or more (including all) of a plurality of feature amounts (e.g., slope, time length from the start of a change to the end of the change, magnitude of the change (difference between a value before the change and a value after the change) may be compared between the observed waveform and the representative waveform, and whether the detected waveform is similar to the representative waveform may be determined based on whether the difference in each feature amount is smaller than a threshold value.

[0046] (System configuration example 2) 3 shows a configuration example 2 of a DC power distribution system in this embodiment. Configuration example 2 is a system that distributes (feeds) power from a power supply device such as a rectifier 60 to a load device 80 inside a base C. Base C is, for example, a building such as a communication building, but is not limited to a building.

[0047] Configuration example 2 is different from configuration example 1 only in scale, and the basic configuration is the same between configuration example 1 and configuration example 2.

[0048] The rectifier 60 converts AC from a commercial power source into DC and outputs DC power. Like the converter A20 in the first configuration example, the rectifier 60 has a voltage conversion unit, an insulating function, and a gate blocking function. The load device 80 is, for example, a device such as a server, and the converter 70 is present inside the load device. The converter 70 has a voltage conversion unit, an insulating function, and a gate blocking function. Also, like the first configuration example, the rectifier 60 has a high-resistance neutral grounding configuration, and is equipped with measuring instruments such as a voltmeter, an ammeter, and a zero-phase current transformer.

[0049] Similarly to the control device 100A, the control device 100B, and the learning device 200 in the configuration example 1, a control device 100C-1, a control device 100C-2, and a learning device 200 are provided. Note that the control device 100C-2 is a functional unit inside the load device 80. The operation in the configuration example 2 is similar to that in the configuration example 1.

[0050] (Configuration example of control device 100) As an example, a configuration example of the control device 100A and the control device 100B in the DC power distribution system shown in Fig. 1 will be described. Here, as an example, it is assumed that the control device 100A performs the determination process, and the control device 100B does not perform the determination process.

[0051] 4 shows an example of the configuration of the control device 100A. As shown in FIG. 4, the control device 100A includes a monitor unit 110, a determination unit 120, a communication unit 130, a control unit 140, a storage unit 150, and a display unit 160.

[0052] The monitoring unit 110 acquires measurement results obtained by measuring instruments (such as a voltmeter and an ammeter) in the site A, and inputs the acquired measurement results to the determination unit 120. The monitoring unit 110 can also acquire device information in the site A (e.g., information on the converter A20).

[0053] The communication unit 130 communicates with other control devices 100 and the learning device 200. More specifically, the communication unit 130 receives the measurement results and device information from the control device 100B at the site B and inputs them to the determination unit 120.

[0054] The judgment unit 120 judges the operating state such as a ground fault (+ side), ground fault (- side), short circuit, partial short circuit, inrush current, load connection, load ON / load OFF, load fluctuation, etc. based on the measurement results input from the monitoring unit 110 and the information input from the communication unit 130.

[0055] For example, threshold values ​​and the like necessary for judgment are stored in the storage unit 150. When making a judgment using the above-mentioned model, the storage unit 150 stores the model (specifically, learned parameters), and the judgment unit 120 reads out the model from the storage unit 150 and uses it for judgment.

[0056] Furthermore, the determination unit 120 may store in the memory unit 150 the determination results of the operating state such as earth fault (+ side), earth fault (- side), short circuit, partial short circuit, inrush current, load connection, load ON / load OFF, and load fluctuation, as well as the voltage waveform, current waveform, or both the voltage waveform and the current waveform corresponding to the determination results. The stored data (data of a pair of the determination result and the waveform) can be used as learning data in the learning device 200. Note that the control device 100A may have a learning function without including the learning device 200.

[0057] When the determination result indicates an accident such as a ground fault or a short circuit, the control unit 140 transmits an abnormality signal for operating a gate block to the converter A20. The display unit 160 displays the determination result and the like.

[0058] 5 is a diagram showing an example of the configuration of a control device 100B at a site B. As shown in FIG.

[0059] The monitoring unit 110 acquires the measurement results measured by each measuring device at site B, and also acquires device information of the load devices at site B. The communication unit 130 transmits the measurement results and device information acquired by the monitoring unit 110 to the control device 100A at site A.

[0060] In the control device 100A, a judgment process is executed, and the judgment result is transmitted to the control device 100B at the site B. For example, if the judgment result indicates the occurrence of an accident, the control unit 140 outputs an abnormality signal that operates the gate block at the site B. In addition, the display unit 160 outputs information indicating that an accident has occurred. Alternatively, the abnormality signal may be transmitted from the control device 100A to the control device 100B at the site B.

[0061] Fig. 6 is a diagram showing an example of the configuration of the learning device 200. As shown in Fig. 6, the learning device 200 has a learning unit 210, a storage unit 220, and a communication unit 230. The communication unit 230 receives learning data (e.g., data of a pair of an event and a waveform) from the control devices 100A, 100B, etc., and stores the learning data in the storage unit 220. The learning unit 210 performs learning using the learning data. For example, as described above, learning of a neural network model is performed. The communication unit 230 transmits the learned model to the control devices 100A, etc.

[0062] <Hardware configuration example> The control devices 100A, 100B, 100C-1, and 100C-2, and the learning device 200 can all be realized, for example, by causing a computer to execute a program. This computer may be a physical computer or a virtual machine.

[0063] That is, the devices (control devices 100A, 100B, 100C-1, 100C-2, learning device 200) can be realized by executing a program corresponding to the processing performed by the devices using hardware resources such as a CPU and memory built into a computer. The programs can be recorded on a computer-readable recording medium (such as a portable memory) and stored or distributed. The programs can also be provided via a network such as the Internet or email.

[0064] Fig. 7 is a diagram showing an example of the hardware configuration of the computer. The computer in Fig. 7 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 via a bus BS.

[0065] The program for realizing 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.

[0066] The memory device 1003 reads out and stores the program from the auxiliary storage device 1002 when an instruction to start the program is received. The CPU 1004 realizes the functions related to the device 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, and functions as a transmitting unit and a receiving unit. The display device 1006 displays a GUI (Graphical User Interface) or the like according to a program. The input device 1007 is composed of a keyboard and mouse, buttons, a touch panel, or the like, and is used to input various operation instructions. The output device 1008 outputs the results of calculations.

[0067] (Operation flow) Next, a detailed operation example of the control device 100A will be described with reference to the flowcharts of Figures 8 and 9. The operation shown in the flowcharts of Figures 8 and 9 is an operation executed by the determination unit 120 of the control device 100A. In addition, the monitored objects assumed in the flowcharts of Figures 8 and 9 are V1, which is the voltage between the positive distribution line and the neutral point (earth), V2, which is the voltage between the negative distribution line and the neutral point (earth), V1+V2=V, which is the voltage between the positive distribution line and the negative distribution line, and the current flowing through the distribution line (for example, the current measured by the ammeter 7 shown in Figure 1).

[0068] In S101, the determination unit 120 detects no fluctuation in any of V1, V2, V, or current, and therefore the DC power distribution system is in a normal state.

[0069] In S102, the determination unit 120 determines whether a fluctuation in voltage (V1, V2, or V) has been detected, and if it has been detected, the process proceeds to S103, and if it has not been detected, the process proceeds to S112. Note that "detecting a fluctuation in voltage" means, for example, detecting that the voltage value at time t+Δt has changed by a threshold value or more compared to the voltage value at time t. The same applies to "detecting a fluctuation in current."

[0070] When a voltage fluctuation is detected (Yes in S102), in S103, the determination unit 120 determines whether the control voltage is being changed based on the information on the state of the converter A20. When a floating-charged storage battery is connected to the target DC power distribution system, in the determination in S103, it is determined whether "(the control voltage is being changed) and (the storage battery is not discharging)". If the determination in S103 is Yes, the process returns to S101; if No, the process proceeds to S104.

[0071] In S104, if the detected voltage fluctuation is a fluctuation of V (= V1 + V2), the process proceeds to S110; if the detected voltage fluctuation is not a fluctuation of V (= V1 + V2), the process proceeds to S105.

[0072] In S105, the determination unit 120 determines whether "V1 < V2". If "V1 < V2", the process proceeds to S106; if not "V1 < V2", the process proceeds to S108.

[0073] In S106 when "V1 < V2", the detection unit 120 determines that a ground fault has occurred in the positive-side power distribution line. When a ground fault occurs in the positive-side power distribution line, since the positive-side power distribution line is grounded through a ground fault resistance (low resistance), the voltage across both ends of the positive-side resistor 1 decreases, the voltage across both ends of the negative-side resistor 2 increases, and "V1 < V2" occurs. In S107, the control unit 140 that has received a ground fault detection notification from the determination unit 120 sends out an abnormal signal.

[0074] When the determination in S105 is No, that is, when "V1 < V2" does not hold, in S108, the detection unit 120 determines that a ground fault has occurred in the negative-side power distribution line. When a ground fault occurs in the negative-side power distribution line, since the negative-side power distribution line is grounded through a ground fault resistance (low resistance), the voltage across both ends of the negative-side resistor 2 decreases, the voltage across both ends of the positive-side resistor 1 increases, and "V1 > V2" occurs. In S109, the control unit 140 that has received a ground fault detection notification from the determination unit 120 sends out an abnormal signal.

[0075] If the determination in S104 is Yes, that is, if a fluctuation in V is detected, in S110, the determination unit 120 determines that a short circuit has occurred. In S111, the control unit 140, which has been notified of the detection of a ground fault by the determination unit 120, sends out an abnormality signal.

[0076] If the determination in S102 is No (that is, if no voltage fluctuation is detected), the determining unit 120 determines in S112 whether or not there is a current fluctuation, and if there is a current fluctuation, the process proceeds to S113.

[0077] In S113, the determination unit 120 determines whether the current value has returned to the value before the current fluctuation after a predetermined time has elapsed since the current fluctuation occurred. If the determination result is No, the process returns to S101. If the determination result is Yes, the process proceeds to S114, where the determination unit 120 determines that an inrush current has occurred. In S115, the control unit 140, which has received a notification of the detection of the inrush current from the determination unit 120, sends an abnormality signal. Note that the inrush current may be considered to be in a normal state, and no abnormality signal may be sent.

[0078] If the determination in S113 is No, that is, if the current has not returned to normal after the lapse of a certain period of time, the process proceeds to S116 in FIG.

[0079] In S116, the determination unit 120 determines whether or not the current rise time is equal to or less than the threshold value. If the determination unit 120 determines that the current rise time is equal to or less than the threshold value, the process proceeds to S117.

[0080] In S117, the determining unit 120 determines, based on the device information received from site B, whether or not a load is being connected or applied at the time of the current rise.

[0081] If the determination result in S117 is No, in S118, the determining unit 120 determines that a partial short circuit has occurred. In S119, the control unit 140, which has been notified of the detection of a partial short circuit by the determining unit 120, sends out an abnormality signal.

[0082] If the determination in S117 is Yes, that is, if the load is currently connected or applied, the process proceeds to S119, where the determination unit 120 determines that the load has been connected or applied, and the process returns to S101.

[0083] If the determination in S116 is No, that is, if the current rise time is not equal to or less than the threshold value, the process proceeds to S120, where the determining unit 120 determines that a load fluctuation has occurred, and the process returns to S101.

[0084] (Judgment based on waveform) 9, more specifically, the determination unit 120 performs a determination based on a waveform corresponding to the event. Note that the "waveform" used in the determination may be the waveform itself (i.e., a value at each time point), or a feature such as a slope (differential), a change time length, etc. may be used as the "waveform."

[0085] FIG. 10 is a diagram showing an image of waveforms corresponding to a ground fault (+), a ground fault (-), and a short circuit when the answer is Yes in S102 in the flow of FIG. 8 (when there is a voltage fluctuation).

[0086] As shown in Fig. 10, when a waveform is detected between a positive distribution line and the earth in which the potential of the positive distribution line suddenly decreases and approaches 0 V, it can be determined that a ground fault (+) has occurred. Also, when a waveform is detected between a negative distribution line and the earth in which the potential of the negative distribution line suddenly increases and approaches 0 V, it can be determined that a ground fault (-) has occurred. The determination in S105 in Fig. 8 may be to determine whether the voltage change corresponds to a waveform having such characteristics.

[0087] Furthermore, when a waveform in which the voltage between the positive distribution line and the negative distribution line suddenly decreases is detected, it can be determined that a short circuit has occurred.

[0088] Figure 10 shows the signals from the load device when each event occurs. If it is known that the load device is operating normally in the "ground fault (+)" and "ground fault (-)" cases, it is possible to determine with greater accuracy that the voltage fluctuation is caused by a ground fault.

[0089] FIG. 11 is a diagram showing an image of waveforms corresponding to an inrush current, a load fluctuation, a partial short circuit, and a load connection / load application when there is a current fluctuation and when S102 in the flow of FIG. 8 is No (when there is no voltage fluctuation).

[0090] As shown in Fig. 11, when an inrush current occurs, the current waveform rises and then immediately returns to the original value. S113 in Fig. 8 corresponds to judging whether the change in the measured current value corresponds to a waveform having such characteristics.

[0091] When a load fluctuation occurs, the current waveform is one in which the current value gradually increases and does not immediately return to the original value. S116 in Fig. 9 corresponds to judging whether the change in the measured current value corresponds to a waveform having such characteristics.

[0092] The waveforms for a partial short circuit and a load connection / closing are similar, with the waveform causing a sudden increase in current. However, in the case of a partial short circuit, no special signal (such as switch ON) is obtained from the load device, whereas in the case of a load connection / closing, a signal such as switch ON is obtained from the load device. In other words, a partial short circuit and a load connection / closing can be distinguished from each other by the waveform and device information. S116 and S117 in Figure 9 correspond to judgments based on the waveform and device information.

[0093] (Effects of the embodiment) As described above, the technology according to the present embodiment makes it possible to avoid erroneously determining that an event such as a load fluctuation is an accident, and to accurately detect an accident that has occurred in a DC power distribution system.

[0094] (Summary of the embodiment) This specification discloses at least the DC power distribution system, the control device, the operation state determination method, and the program described in the following items. (Section 1) A DC power distribution system that distributes power from a power supply device to a load device through a power distribution network, A meter provided in the power distribution network; a control device including a determination unit that acquires voltage values ​​and current values ​​measured by the measuring device and determines an operating state of the DC power distribution system based on a waveform indicating a change in the voltage value and a waveform indicating a change in the current value; A DC power distribution system comprising: (Section 2) The control device includes: and a control unit that, when the determination unit determines that an accident has occurred in the power distribution network, operates a gate block provided in the power supply device to stop power distribution from the power supply device. 2. A DC power distribution system as described in paragraph 1. (Section 3) The determination unit calculates an impedance from the voltage value and the current value acquired by the measuring instrument, and estimates a distance from the measuring instrument to an accident point based on the calculated impedance. 3. A DC power distribution system as described in paragraph 2. (Section 4) The determination unit determines whether a partial short circuit has occurred or whether a load has been connected or turned on based on a waveform indicating a change in current value and device information obtained from the load device. 4. A DC power distribution system according to any one of claims 1 to 3. (Section 5) A learning device that learns a model that outputs an operating state corresponding to an input waveform based on an operating state in the DC power distribution system and a waveform of a voltage value or a current value corresponding to the operating state. 5. The DC power distribution system according to any one of claims 1 to 4, further comprising: (Section 6) 1. A method for determining an operating state in a DC power distribution system that distributes power from a power supply device to a load device through a power distribution network, comprising: A step of measuring voltage and current values ​​using a measuring instrument installed in the power distribution network.

[0095] acquiring voltage values ​​and current values ​​measured by the measuring instruments, and determining an operating state of the DC power distribution system based on a waveform indicating a change in the voltage value and a waveform indicating a change in the current value; An operating state determination method comprising: (Section 7) A control device used in a DC power distribution system that distributes power from a power supply device to a load device through a power distribution network, comprising: and a determination unit that acquires voltage values ​​and current values ​​measured by a measuring instrument provided in the power distribution network and determines an operating state of the DC power distribution system based on a waveform indicating a change in the voltage value and a waveform indicating a change in the current value. Control device. (Section 8) A program for causing a computer to function as a control device described in Lecture 7.

[0096] Although the present embodiment has been described above, the present invention is not limited to such a specific embodiment, and various modifications and variations are possible within the scope of the gist of the present invention described in the claims. [Explanation of symbols]

[0097] 1, 2, 1, 42 Resistor 3, 4, 9, 43, 44, 49 Voltmeter 6, 7, 8, 10, 46, 47, 48, 50 ammeter 20, 30, 70 Converter 100 Control device 110 Monitoring Department 120 Judgment section 130 Communications Department 140 Control section 150 Storage section 160 Display section 200 Learning Device 210 Learning Department 220 Storage section 230 Communications Department 80 Loading device 1000 Drive Device 1001 Recording media 1002 Auxiliary storage 1003 Memory device 1004 CPU 1005 Interface device 1006 Display device 1007 Input Device

Claims

1. A DC power distribution system that distributes power from a power supply device to a load device through a power distribution network, A meter provided in the power distribution network; a control device including a determination unit that acquires voltage values ​​and current values ​​measured by the measuring instruments and determines an operating state of the DC power distribution system based on a waveform indicating a change in the voltage value and a waveform indicating a change in the current value; The operating state is a ground fault, a short circuit, a partial short circuit, an inrush current, a load connection, a load ON / load OFF, or a load change; The determination unit determines whether a partial short circuit has occurred or whether a load has been connected or turned on based on a waveform indicating a change in current value and device information obtained from the load device. DC power distribution system.

2. The control device includes: and a control unit that, when the determination unit determines that an accident has occurred in the power distribution network, operates a gate block provided in the power supply device to stop power distribution from the power supply device.

2. The DC power distribution system according to claim 1.

3. The determination unit calculates an impedance from the voltage value and the current value acquired by the measuring instrument, and estimates a distance from the measuring instrument to an accident point based on the calculated impedance.

3. The DC power distribution system according to claim 2.

4. A learning device that learns a model that outputs an operating state corresponding to an input waveform based on an operating state in the DC power distribution system and a waveform of a voltage value or a current value corresponding to the operating state.

4. The DC power distribution system according to claim 1, further comprising:

5. 1. A method for determining an operating state in a DC power distribution system that distributes power from a power supply device to a load device through a power distribution network, comprising: A measuring device installed in the power distribution network measures a voltage value and a current value; a determination step of acquiring the voltage value and the current value measured by the measuring instrument, and determining an operating state of the DC power distribution system based on a waveform indicating a change in the voltage value and a waveform indicating a change in the current value, The operating state is a ground fault, a short circuit, a partial short circuit, an inrush current, a load connection, a load ON / load OFF, or a load change; In the determining step, it is determined whether a partial short circuit has occurred or whether a load has been connected or turned on based on a waveform indicating a change in current value and device information obtained from the load device. Operational state determination method.

6. A control device used in a DC power distribution system that distributes power from a power supply device to a load device through a power distribution network, comprising: a determination unit that acquires voltage values ​​and current values ​​measured by a measuring device provided in the power distribution network, and determines an operating state of the DC power distribution system based on a waveform indicating a change in the voltage value and a waveform indicating a change in the current value; The operating state is a ground fault, a short circuit, a partial short circuit, an inrush current, a load connection, a load ON / load OFF, or a load change; The determination unit determines whether a partial short circuit has occurred or whether a load has been connected or turned on based on a waveform indicating a change in current value and device information obtained from the load device. Control device.

7. A program for causing a computer to function as the control device according to claim 6.

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