Power generation estimation device, power supply system, and power generation estimation method

Abstract

To easily estimate the amount of power generated by a distributed power supply device of a customer when power is supplied to the customer by a mobile power source vehicle.SOLUTION: In a power supply path 4 that connects a device 2 on the power transmission side and devices 5_1 to 5_n on the power receiving side including a distributed power supply device 50 having a grid connection protection relay, a power generation amount estimation device 3 according to a representative embodiment of the present invention estimates the power generation amount of the distributed power supply device 50 on the basis of a difference Δi between a measured value i0 of a current i flowing from the power transmission side to the power receiving side in a state in which the grid connection protection relay of the distributed power supply 50 is not operating, and the measured value i2 of the current in the state in which the grid connection protection relay of the distributed power supply is in operation.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a power generation estimation device, a power supply system, and a power generation estimation method, and relates to a technique for estimating the amount of power generated by a distributed power supply device, for example, when power is supplied from a mobile power supply vehicle to a consumer equipped with a distributed power supply device. [Background technology]

[0002] Power supply vehicles (mobile power supply vehicles) are generally known as temporary power sources that supply electricity to customers in buildings and ordinary homes during large-scale power outages caused by disasters, during construction and inspection of power distribution lines, etc. A mobile power supply vehicle is a mobile private power generation device that is equipped with a prime mover, generator, and auxiliary equipment on a vehicle such as a truck or trailer.

[0003] In recent years, there are cases where a distributed power supply device such as a photovoltaic apparatus is installed at a consumer to which a mobile power supply vehicle is connected and is connected to a power distribution system. When power is supplied from a mobile power supply vehicle to such a consumer, if the distributed power supply device generates power that exceeds the consumer's demand, a reverse power flow of power occurs from the distributed power supply device to the mobile power supply vehicle.

[0004] When a reverse power flow occurs, the generator of a mobile power supply vehicle will stop. Once the generator of a mobile power supply vehicle stops, it takes time to restart the generator, and a power outage occurs during that time. Therefore, when using a mobile power supply vehicle, it is extremely important not to stop the generator.

[0005] Conventionally, a technique for preventing reverse power flow to a mobile power supply vehicle is known in which a resistor is connected to the generator of the mobile power supply vehicle (see, for example, Patent Document 1). According to this, power is constantly consumed by the resistor, so the occurrence of reverse power flow to the mobile power supply vehicle is prevented, and it is possible to avoid the generator of the mobile power supply vehicle stopping. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2020-32770 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, if a resistor is constantly connected to the generator of a mobile power supply vehicle, power will be constantly consumed in the resistor, resulting in unnecessary consumption of fuel for the prime mover used to drive the generator, shortening the operating time of the mobile power supply vehicle and reducing the efficiency of the mobile power supply vehicle.

[0008] Therefore, the inventors of the present application thought that if it were possible to estimate the amount of power generated by a distributed power supply device when the mobile power supply vehicle supplies power to a consumer to which the distributed power supply device is connected, it would be possible to grasp the risk of the mobile power supply vehicle's generator stopping due to reverse power flow and take appropriate countermeasures.

[0009] The present invention has been made in consideration of the above-mentioned problems, and has an object to make it possible to easily estimate the amount of power generated by a consumer's distributed power supply device when power is supplied to the consumer by a mobile power supply vehicle. [Means for solving the problem]

[0010] A power generation estimation device according to a representative embodiment of the present invention is characterized in that, in a power supply path connecting an apparatus on the power transmission side and an apparatus on the power receiving side including a distributed power supply device having a grid interconnection protective relay, it estimates the power generation amount of the distributed power supply device based on the difference between a measured value of a current flowing from the power transmission side to the power receiving side when the grid interconnection protective relay of the distributed power supply device is not operating and a measured value of the current when the grid interconnection protective relay of the distributed power supply device is operating. Effect of the Invention

[0011] The power generation amount estimation device according to the present invention makes it possible to easily estimate the amount of power generated by a distributed power supply device of a consumer when power is supplied to the consumer by a mobile power supply vehicle. [Brief description of the drawings]

[0012] [Figure 1] 1 is a diagram showing a configuration of a power supply system including a power generation amount estimation device according to a first embodiment of the present invention. [Diagram 2] 1 is a diagram showing a specific configuration of a mobile power supply vehicle and a power generation amount estimation device in a power supply system according to a first embodiment of the present invention. [Diagram 3] 1 is a diagram for explaining a method for estimating the power generation amount of a distributed power supply device by the power generation amount estimation device according to the first embodiment. FIG. [Figure 4] 5 is a flowchart showing an example of the flow of a power generation amount estimation process performed by the power generation amount estimation device according to the first embodiment. [Diagram 5] FIG. 11 is a diagram showing a specific configuration of a mobile power supply vehicle and a power generation amount estimation device in a power supply system according to a second embodiment. [Figure 6] 1 is a diagram for explaining the relationship between the amount of power generated by a photovoltaic power generation device as a distributed power supply device and the amount of solar radiation. [Figure 7] 10 is a flowchart showing a process flow for estimating the amount of power generation from the amount of solar radiation performed by the power generation amount estimation device according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] 1. Overview of the embodiment First, a typical embodiment of the invention disclosed in this application will be outlined. In the following description, as an example, reference numerals in the drawings corresponding to components of the invention are given in parentheses.

[0014] [1] A power generation amount estimation device (3, 3A) according to a representative embodiment of the present invention is characterized in that, in a power supply path (4) connecting a power transmission side device (2) and a power receiving side device (5_1 to 5_n) including a distributed power supply device (50) having a grid interconnection protective relay, the device estimates the power generation amount of the distributed power supply device based on a difference (Δi) between a measurement value (i0, i1) of a current (i) flowing from the power transmission side to the power receiving side when the grid interconnection protective relay of the distributed power supply device is not operating, and a measurement value (i2) of the current when the grid interconnection protective relay of the distributed power supply device is operating.

[0015] [2] In the power generation amount estimation device (3, 3A) described in the above [1], a current value acquisition unit (31) that acquires a measurement value of the current, a power generation amount calculation unit (32, 32A) that calculates an estimate of the power generation amount of the distributed power supply device connected to the power supply path based on the measurement value of the current acquired by the current value acquisition unit, and a power generation amount calculation unit (32, 32A) that outputs an instruction signal (Sd) to a device on the power transmission side to instruct whether or not to operate the grid interconnection protective relay of the distributed power supply device and controls the current value acquisition unit and the power generation amount calculation unit. and a control unit (30) that executes a power generation estimation process for estimating the power generation amount of the distributed power supply device by performing a power generation amount estimation process, and the power generation amount calculation unit may calculate an estimate of the power generation amount of the distributed power supply device based on a difference (Δiu, Δid) between the measurement value (i0, i1) of the current when the grid interconnection protective relay of the distributed power supply device is not operating and the measurement value (i2) of the current when the grid interconnection protective relay of the distributed power supply device is operating, and a voltage value of the power supply path, in the power generation amount estimation process.

[0016] [3] In the power generation amount estimation device (3, 3A) described in [2] above, the power generation amount calculation unit (32, 32A) may calculate the difference multiple times and calculate an estimate of the power generation amount of the distributed power supply device based on an average value (Δia) of the multiple differences.

[0017] [4] In the power generation amount estimation device (3, 3A) described in [3] above, the power generation amount calculation unit (32, 32A) may calculate the difference (Δiu) when a transition occurs from a state in which the grid interconnection protective relay of the distributed power supply device is not operating to a state in which the grid interconnection protective relay of the distributed power supply device is operating, and the difference (Δid) when a transition occurs from a state in which the grid interconnection protective relay of the distributed power supply device is operating to a state in which the grid interconnection protective relay of the distributed power supply device is not operating.

[0018] [5] In the power generation amount estimation device (3, 3A) described in [4] above, when the variation of the calculated differences exceeds an allowable value, the control unit may stop the power generation amount estimation process and resume the power generation amount estimation process after a predetermined period of time has elapsed.

[0019] [6] In the power generation amount estimation device (3, 3A) described in any one of [2] to [5] above, the control unit may start the power generation amount estimation process at a preset time.

[0020] [7] The power generation estimation device (3A) described in any one of [2] to [6] above may further include a solar radiation acquisition unit (33) that acquires a measured value of solar radiation, and the distributed power supply device may be a solar power generation device, and the power generation calculation unit may calculate the estimated power generation amount (Px) from the measured value of solar radiation (hx) based on a correlation between the estimated power generation amount (P1) calculated by the power generation estimation process and the measured value of solar radiation (h1) at that time.

[0021] [8] A power supply system (1) according to a representative embodiment of the present invention comprises a power generation estimation device (3, 3A) described in any one of [2] to [7] above, and a mobile power supply vehicle (2) as the power transmission side device that supplies power to the power supply path, and the mobile power supply vehicle is characterized in that it operates the grid interconnection protective relay of the distributed power supply device in response to the instruction signal.

[0022] [9] In the power supply system described in [8] above, the mobile power supply vehicle may change the voltage supplied to the power supply path to operate the grid-connection protective relay of the distributed power supply device.

[0023]

[10] In the power supply system described in [8] above, the mobile power supply vehicle may change the frequency of the voltage supplied to the power supply path to operate the grid-connection protective relay of the distributed power supply device.

[0024]

[11] A power generation estimation method according to a representative embodiment of the present invention is characterized in that it includes a first step (S1, S6) of measuring a current flowing from a power transmission side to a power receiving side in a power supply path connecting an apparatus on a power transmission side and an apparatus on a power receiving side including a distributed power supply apparatus having a grid-connection protective relay when the grid-connection protective relay of the distributed power supply apparatus is not in operation, a second step (S3) of measuring the current when the grid-connection protective relay of the distributed power supply apparatus is in operation, a third step (S4, S7) of calculating a difference between the measured current value obtained in the first step and the measured current value obtained in the second step, and a fourth step (S10) of estimating the power generation amount of the distributed power supply apparatus based on the difference calculated in the third step.

[0025] 2. Specific examples of embodiments DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific examples of embodiments of the present invention will be described with reference to the drawings. In the following description, components common to the respective embodiments are designated by the same reference numerals, and repeated description will be omitted.

[0026] First Embodiment FIG. 1 is a diagram showing a configuration of a power supply system including a power generation amount estimation device according to a first embodiment of the present invention.

[0027] The power supply system 1 shown in Fig. 1 is a mobile system that supplies self-generated power to the outside, and supplies power to consumers such as buildings, general homes, etc. As shown in Fig. 1, the power supply system 1 includes, for example, a mobile power supply vehicle 2 and a power generation amount estimation device 3.

[0028] The mobile power supply vehicle 2 is a mobile private power generation device that is equipped with a prime mover, generator, and auxiliary equipment on a vehicle such as a truck or trailer. The mobile power supply vehicle 2 supplies the power that it generates to consumers via a power supply path 4. The power supply path 4 is for connecting a device on the power transmission side and a device on the power receiving side to realize power transmission, and is realized by, for example, a power distribution line, a transformer, etc.

[0029] FIG. 1 illustrates an example in which the consumer is a general household, but the consumer is not limited to this and may be a building, a factory, or the like.

[0030] The consumer facility 5 as a power receiving device includes, for example, a consumer load 51 and a distributed power supply device 50 that supplies power to the consumer load 51. The consumer load 51 is a device that can be operated by power from an electric device or the like installed in the consumer's facility.

[0031] The distributed power supply device 50 is a private power generation device that supplies the power that it generates to a consumer load 51. The distributed power supply device 50 may store the generated power. The distributed power supply device 50 is linked to a power distribution system, and is capable of supplying the power generated or stored in the distributed power supply device 50 to the power distribution system. Examples of the distributed power supply device 50 include a solar power generation device and a home fuel cell.

[0032] In this embodiment, as an example, the distributed power supply device 50 will be described as a photovoltaic power generation device (PV). For example, a photovoltaic power generation device as the distributed power supply device 50 is connected to a wiring system via a photovoltaic power generation power converter (PCS) 52 and a high-frequency removal filter (not shown). In addition, a consumer load 51 is connected to the wiring system via a transformer, and three-phase power of the distribution system is stepped down to single-phase power for home use and supplied to the consumer load 51.

[0033] Also, in this embodiment, the mobile power supply vehicle 2 is described as supplying power to multiple consumer equipment 5_1 to 5_n (n is an integer equal to or greater than 2) via the power supply path 4, but there may be only one consumer equipment 5 receiving power supply from the mobile power supply vehicle 2. Furthermore, it is sufficient that at least one of the consumer equipment 5_1 to 5_n receiving power supply from the mobile power supply vehicle 2 is equipped with a distributed power supply unit 50, and it is not necessary that all of the consumer equipment 5_1 to 5_n are equipped with a distributed power supply unit 50.

[0034] The distributed power supply device 50 includes a grid-connection protective relay 53. The grid-connection protective relay 53 is built into the PCS 52, for example.

[0035] Here, the grid interconnection protective relay 53 is a relay for protecting a grid such as the power supply path 4. The grid interconnection protective relay 53 stops when the voltage or frequency of the power supply path 4 is within a range determined by a preset allowable value (setting value), and operates when the voltage or frequency of the power supply path 4 exceeds the range determined by the setting value.

[0036] Here, the setting value is a voltage or frequency value that serves as a reference for determining whether or not the grid interconnection protective relay 53 is to be operated.

[0037] Specifically, the grid-connection protective relay 53 enables the distributed power supply device 50 to be connected to the grid when the voltage or frequency of the power supply path 4 is within a range determined by a set value. In other words, the grid-connection protective relay 53 enables the output of power from the distributed power supply device 50 (output of power to the power supply path 4 and the consumer load 51).

[0038] On the other hand, when the voltage or frequency of the power supply path 4 exceeds the range determined by the set value, the grid-connection protective relay 53 stops the connection of the distributed power supply device 50 to the grid. In other words, the grid-connection protective relay 53 stops the output of power from the distributed power supply device 50 (the output of power to the power supply path 4 and the consumer load 51).

[0039] The grid-connection protection relay 53 includes, for example, an overvoltage relay (OVR), an undervoltage relay (UVR), an overfrequency relay (OFR), and an underfrequency relay (UFR).

[0040] The overvoltage relay (OVR) operates when the voltage of the power supply path 4 exceeds a set value (e.g., 107 V) and stops the supply of power from the distributed power supply device 50 to the power distribution system (power supply path 4) and the consumer load 51.

[0041] The undervoltage relay (UVR) operates when the voltage of the power supply path 4 falls below a set value (e.g., 95 V) and stops the supply of power from the distributed power supply device 50 to the power distribution system (power supply path 4) and consumer loads 51.

[0042] The over-frequency relay (OFR) operates when the frequency of the power supply path 4 exceeds a set value (e.g., 51 Hz) and stops the supply of power from the distributed power supply device 50 to the power distribution system (power supply path 4) and the consumer load 51.

[0043] The under frequency relay (UFR) operates when the frequency of the power supply path 4 falls below a set value (e.g., 48.5 Hz) and stops the supply of power from the distributed power supply device 50 to the power distribution system (power supply path 4) and consumer loads 51.

[0044] The power generation amount estimation device 3 is a device that estimates the amount of power generated by the distributed power generation devices 50 in the customer facilities 5_1 to 5_n on the power receiving side of the power from the mobile power supply vehicle 2. The power generation amount estimation device 3 will be described in detail later.

[0045] The power supply system 1 supplies power generated by a mobile power supply vehicle 2 to each consumer equipment 5_1 to 5_n via the power supply path 4 in a state in which the connection between a power transmission equipment (e.g., a transformer at a substation or a pole-mounted transformer) that supplies AC power in a three-phase, three-wire system and a power supply path 4 (e.g., a distribution line) is cut off, for example, during a large-scale power outage due to a disaster or during construction and inspection of a distribution line.

[0046] FIG. 2 is a diagram showing a specific configuration of the mobile power supply vehicle 2 and the power generation amount estimation device 3 in the power supply system 1 according to the first embodiment of the present invention.

[0047] 2, the mobile power supply vehicle 2 has, for example, a power generation control device 20, a prime mover 21, a generator 22, and a circuit breaker 23. Power (mechanical energy) generated by the prime mover 21 is transmitted to the generator 22, and the generator 22 generates power using the power. The power generated by the generator 22 is output to the power supply path 4 via the circuit breaker 23.

[0048] The circuit breaker 23 is a device that switches between connection and disconnection between the generator 22 and the power supply path 4. The power generation control device 20 is a device that controls each device of the mobile power supply vehicle 2 and provides overall control of the operation of the mobile power supply vehicle 2.

[0049] The power generation control device 20 is configured to include, for example, a program processing device including various memories and a processor that executes various calculations according to programs stored in the memories, various peripheral circuits controlled by the program processing device, and a user interface such as an operation panel for inputting operations from the user.

[0050] The power generation control device 20 controls the prime mover 21 and the generator 22 to generate power in response to instructions input, for example, via a user interface, and controls the opening and closing of the circuit breaker 23 to switch between outputting and stopping power from the mobile power supply vehicle 2.

[0051] In addition, as will be described in detail later, the power generation control device 20, in response to an instruction signal Sd from the power generation amount estimation device 3, controls the generator 22 to operate the grid-connection protective relay 53 of the distributed power supply device 50 in each of the consumer equipment 5_1 to 5_n, thereby stopping the output of power from the distributed power supply device 50 to the power supply path 4 and the consumer load 51.

[0052] The power generation estimation device 3 estimates the power generation amount of the distributed power supply device 50 based on the difference between the measurement value of the current i flowing from the power transmitting side (mobile power supply vehicle 2) to the power receiving side (distributed power supply device 50) in the power supply path 4 when the grid interconnection protective relay 53 of the distributed power supply device 50 is not operating, and the measurement value of the current i when the grid interconnection protective relay 53 of the distributed power supply device 50 is operating.

[0053] As described above, a state in which the grid interconnection protective relay 53 of the distributed power supply device 50 is not operating (stopped) means that the distributed power supply device 50 is able to output power to the power supply path 4 and the consumer load 51, and a state in which the grid interconnection protective relay 53 of the distributed power supply device 50 is operating means that the output of power by the distributed power supply device 50 to the power supply path 4 and the consumer load 51 is stopped.

[0054] 2, the power generation amount estimation device 3 includes a control unit 30, a current value acquisition unit 31, and a power generation amount calculation unit 32. The power generation amount estimation device 3 can be realized by, for example, an information processing device such as a personal computer.

[0055] The current value acquiring unit 31 is a functional unit that acquires a measurement value of a current i that flows in the power supply path 4 from the power transmission (mobile power supply vehicle 2) side to the power receiving (each of the consumer equipment 5_1 to 5_n) side.

[0056] For example, the current i is measured by an ammeter installed on the power supply path 4, or an ammeter in the mobile power supply vehicle 2. The current value acquisition unit 31 acquires the measurement value of the current i from these ammeters.

[0057] The power generation amount calculation unit 32 is a functional unit that calculates an estimate of the power generation amount of the distributed power supply device 50 connected to the power supply path 4 based on the measurement value of the current i acquired by the current value acquisition unit 31.

[0058] The control unit 30 is a functional unit that performs overall control of the power generation amount estimation device 3. The control unit 30 outputs an instruction signal Sd that instructs the power transmission side device (mobile power supply vehicle 2) whether or not to operate the grid interconnection protective relay 53 of the distributed power supply device 50, and also controls the current value acquisition unit 31 and the power generation amount calculation unit 32 to execute a power generation amount estimation process for estimating the power generation amount of the distributed power supply device 50.

[0059] The above-mentioned control unit 30, current value acquisition unit 31, and power generation amount calculation unit 32 are realized, for example, by program processing by the above-mentioned information processing device.

[0060] Specifically, in the power generation estimation process, the power generation calculation unit 32 calculates an estimate of the power generation amount of the distributed power supply device 50 based on the difference Δi between the measured value of the current i when the grid-connection protective relay 53 of the distributed power supply device 50 is not operating and the measured value of the current i when the grid-connection protective relay 53 is operating, and the value of the voltage of the power supply path 4.

[0061] The power generation amount calculation unit 32 calculates the difference Δi multiple times, and calculates an estimate of the power generation amount of the distributed power supply device 50 based on an average value Δia of the multiple differences Δi. For example, the power generation amount calculation unit 32 calculates a difference Δiu when a transition occurs from a state in which the grid interconnection protective relay 53 of the distributed power supply device 50 is not operating to a state in which the grid interconnection protective relay 53 of the distributed power supply device 50 is operating, and a difference Δid when a transition occurs from a state in which the grid interconnection protective relay 53 of the distributed power supply device 50 is operating to a state in which the grid interconnection protective relay 53 of the distributed power supply device 50 is not operating, and calculates an estimate of the power generation amount of the distributed power supply device 50 based on an average value Δia of the difference Δiu and the difference Δid.

[0062] The estimated value of the power generation amount calculated by the power generation amount calculation unit 32 is the sum of the power generation amounts of the distributed power generation devices 50 that are connected to the power supply path 4 and are generating power.

[0063] The power generation amount estimation process will be described in detail below with reference to FIG. 3 and FIG.

[0064] FIG. 3 is a diagram for explaining a method for estimating the power generation amount of the distributed power generation device 50 by the power generation amount estimation device 3 according to the first embodiment.

[0065] 3, the horizontal axis represents time and the vertical axis represents current i. Reference numeral 301 represents a change over time in current i that flows from the mobile power supply vehicle 2 on the power transmission side to customer equipment 5_1 to 5_n on the power receiving side in the power supply path 4.

[0066] FIG. 4 is a flowchart showing an example of the flow of the power generation amount estimation process performed by the power generation amount estimation device 3 according to the first embodiment.

[0067] Here, as an example, the initial state of the entire system is a state in which the grid-connection protective relays 53 of the distributed power sources 50 in the consumer facilities 5_1 to 5_n are not operating and the power supply from the mobile power supply vehicle 2 to the consumer facilities 5_1 to 5_n is stable, i.e., a state in which the current i flowing from the mobile power supply vehicle 2 to the consumer facilities 5_1 to 5_n is stable. Note that a state in which the power (current i) is stable refers to, for example, a state in which the fluctuation of the power (current i) is within ±10%.

[0068] In an initial state, for example, when a user operates the power generation amount estimation device 3 to instruct execution of the power generation amount estimation process, the control unit 30 of the power generation amount estimation device 3 starts the power generation amount estimation process.

[0069] In the power generation amount estimation process, first, the control unit 30 controls the current value acquisition unit 31 to acquire a current value i when the grid-connection protective relay 53 of each distributed power supply device 50 is not operating (step S1). For example, at time t1 in Fig. 3, the current value acquisition unit 31 acquires a measured value i0 of a current flowing through the power supply path 4 from an ammeter installed in the power supply path 4.

[0070] Next, the control unit 30 stops the operation of each of the distributed power supply devices 50 of the customer facilities 5_1 to 5_n, for example, at time t2 in FIG. 3 (step S2).

[0071] Specifically, the control unit 30 of the power generation estimation device 3 outputs an instruction signal Sd to the mobile power supply vehicle 2 instructing it to operate the grid-connection protective relay 53 of the distributed power supply unit 50, and the power generation control device 20 of the mobile power supply vehicle 2 controls the generator 22 in accordance with the instruction signal Sd to change at least one of the output voltage and frequency of the generator 22, thereby stopping the supply of power to the power supply path 4 and the consumer load 51 by each distributed power supply unit 50.

[0072] For example, the power generation control device 20 increases the voltage supplied from the generator 22 to the power supply path 4. As a result, the grid-connection protective relay 53 of each distributed power supply device 50 determines that the voltage of the power supply path 4 has exceeded a range determined by a preset setting value, and stops the output of power from the distributed power supply device 50 to the power supply path 4 and the consumer load 51.

[0073] At this time, instead of increasing the voltage, the power generation control device 20 may change the frequency of the voltage supplied from the generator 22 to the power supply path 4 (raise or lower the frequency). In this case as well, the grid-connection protective relay 53 of each distributed power supply device 50 determines that the frequency of the power supply path 4 has exceeded the range determined by the set value, and stops the output of power from the distributed power supply device 50 to the power supply path 4 and the consumer load 51.

[0074] As shown in Figure 3, after the operation of the distributed power supply device 50 is stopped at time t2, power is supplied to the consumer loads 51 of each of the consumer equipment 5_1 to 5_n only from the mobile power supply vehicle 2, so the power supplied from the mobile power supply vehicle 2 to each of the consumer equipment 5_1 to 5_n, i.e., the current i in the power supply path 4, increases.

[0075] Thereafter, at time t3 when the current i (power supplied from the mobile power supply vehicle 2) becomes stable, the control unit 30 controls the current value acquisition unit 31 to acquire the current value i in a state in which the grid-connection protective relay 53 of each distributed power supply device 50 is operating (step S3). For example, at time t3 in Fig. 3, the current value acquisition unit 31 acquires the measurement value i2 of the current flowing through the power supply path 4 from an ammeter installed on the power supply path 4.

[0076] Next, the control unit 30 controls the power generation amount calculation unit 32 to calculate the difference Δiu (=|i2-i0|) between the current value i2 obtained in step S3 when the grid-connection protective relay 53 of the distributed power supply device 50 is in operation and the current value i0 obtained in step S1 when the grid-connection protective relay 53 of the distributed power supply device 50 is not in operation (step S4).

[0077] Next, the control unit 30 resumes the operation of each of the distributed power supply devices 50 of the customer facilities 5_1 to 5_n, for example, at time t4 in FIG. 3 (step S6).

[0078] Specifically, the control unit 30 outputs an instruction signal Sd to the mobile power supply vehicle 2 instructing it to stop the grid-connection protective relay 53 of the distributed power supply device 50, and the power generation control device 20 of the mobile power supply vehicle 2 controls the generator 22 in accordance with the instruction signal Sd to restore the output voltage or frequency of the generator 22, which was changed in step S2, to its normal value.

[0079] For example, the power generation control device 20 reduces the voltage of the power supply path 4, which was increased in step S2, to a normal value. As a result, the grid-connection protective relay 53 of each distributed power supply device 50 determines that the voltage of the power supply path 4 is within the range determined by the set value, and again enables the supply of power from the distributed power supply device 50 to the power supply path 4 and the consumer load 51.

[0080] As shown in Figure 3, after the operation of the distributed power supply unit 50 resumes at time t4, power is supplied to the consumer loads 51 of each of the consumer facilities 5_1 to 5_n from the mobile power supply vehicle 2 and the distributed power supply unit 50, respectively, so that the power supplied from the mobile power supply vehicle 2 to each of the consumer facilities 5_1 to 5_n, i.e., the current i in the power supply path 4, decreases.

[0081] Thereafter, at time t5 when the current i becomes stable, the control unit 30 controls the current value acquiring unit 31 to again acquire the current value i in a state in which the grid-connection protective relay 53 of each distributed power supply device 50 is not operating (step S6). For example, at time t5 in Fig. 3, the current value acquiring unit 31 acquires the measurement value i1 of the current flowing through the power supply path 4 from an ammeter installed on the power supply path 4.

[0082] Next, the control unit 30 controls the power generation amount calculation unit 32 to calculate the difference Δid (=|i1-i2|) between the current value i2 obtained in step S3 when the grid-connection protective relay 53 of the distributed power supply device 50 is not operating and the current value i1 obtained in step S6 when the grid-connection protective relay 53 of the distributed power supply device 50 is not operating (step S7).

[0083] Next, the control unit 30 determines whether the variation of the calculated differences Δi exceeds a tolerance (step S8). For example, the control unit 30 determines whether the difference |iu-id| between Δiu calculated in step S4 and Δid calculated in step S7 exceeds a predetermined threshold value ith.

[0084] If the difference |iu-id| does not exceed the predetermined threshold value ith (step S8: NO), the control unit 30 controls the power generation amount calculation unit 32 to calculate the average value of the calculated differences Δi (step S9). Specifically, the control unit 30 controls the power generation amount calculation unit 32 to calculate the average value Δia of Δiu calculated in step S4 and Δid calculated in step S7.

[0085] Next, the power generation amount calculation unit 32 calculates an estimate of the power generation amount of the distributed power supply device 50 connected to the power supply path 4 (step S10). Specifically, the power generation amount calculation unit 32 multiplies the average value Δia of the differences calculated in step S9 by the value of the voltage supplied to the power supply path 4 to calculate the estimate of the power generation amount of the distributed power supply device 50.

[0086] On the other hand, in step S8, if the difference |iu-id| exceeds the predetermined threshold value ith (step S8: YES), it can be determined that the power in the power supply path 4 is not stable, so the control unit 30 stops the power generation amount estimation process and starts measuring time (step S11).

[0087] After step S11, the control unit 30 determines whether or not a certain period of time has elapsed since the power generation amount estimation process was stopped (step S12). The control unit 30 continues to stop the power generation amount estimation process until the certain period of time has elapsed.

[0088] If the certain period has elapsed (step S12: YES), the control unit 30 resumes the power generation amount estimation process. Specifically, the control unit 30 returns to step S1 and re-executes the processes from step S1 to step S12.

[0089] As described above, the power generation amount estimation device 3 of embodiment 1 estimates the power generation amount of the distributed power supply device 50 based on the difference Δi between the measured value of the current i flowing from the power transmission side to the power receiving side when the grid interconnection protective relay 53 of the distributed power supply device 50 is not operating, and the measured value of the current i when the grid interconnection protective relay 53 of the distributed power supply device 50 is operating, in the power supply path 4 connecting the mobile power supply vehicle 2 as the power transmission side device and consumer equipment 5_1 to 5_n including the distributed power supply device 50 having the grid interconnection protective relay 53.

[0090] Specifically, as described above, the power generation amount estimation device 3 has a current value acquisition unit 31 that acquires a measurement value of the current i, a power generation amount calculation unit 32 that calculates an estimate of the power generation amount of the distributed power supply device 50 connected to the power supply path 4 based on the measurement value of the current i, and a control unit 30 that outputs an instruction signal Sd instructing the mobile power supply vehicle 2 whether or not to operate the grid-connection protective relay 53 of the distributed power supply device 50 and controls the current value acquisition unit 31 and the power generation amount calculation unit 32 to execute the power generation amount estimation process. In the power generation amount estimation process, the power generation amount calculation unit 32 calculates an estimate of the power generation amount of the distributed power supply device 50 based on the difference Δi between the measurement value of the current i when the grid-connection protective relay 53 of the distributed power supply device 50 is not operating and the measurement value of the current i when the grid-connection protective relay 53 is operating, and the value of the voltage of the power supply path 4.

[0091] According to this, by measuring the current i when the grid-connection protective relay 53 of the distributed power supply device 50 is not operating, i.e., when the distributed power supply device 50 is generating power and power is being supplied from the distributed power supply device 50 and the mobile power supply vehicle 2 to the consumer loads 51, it is possible to estimate the amount of power consumed by all of the consumer loads 51 that is supplied by the mobile power supply vehicle 2. On the other hand, by measuring the current i when the grid-connection protective relay 53 of the distributed power supply device 50 is operating, i.e., when the output of power from the distributed power supply device 50 to the power supply path 4 and the consumer loads 51 is stopped, it is possible to estimate the power consumption of all of the consumer loads 51.

[0092] By calculating the difference in current i (difference in power) between these two states, it is possible to estimate the power supplied by the distributed power supply system 50 to drive the consumer load 51. By regarding this estimated power as the amount of power generated by the distributed power supply system 50, it becomes possible to easily estimate the amount of power generated by the distributed power supply system 50.

[0093] In this way, the power generation estimation device 3 of this embodiment can easily estimate the power generation amount of the distributed power generation devices 50 connected to the power supply path 4 without individually measuring the power generation amount of the distributed power generation devices 50 installed in each consumer equipment 5_1 to 5_n.

[0094] According to this, when the mobile power supply vehicle 2 is used as a temporary power source during a large-scale power outage or during construction and inspection of power distribution lines, the manager of the mobile power supply vehicle 2, etc., can grasp in advance the risk of reverse power flow occurring and causing the generator 22 of the mobile power supply vehicle 2 to stop, and can appropriately determine the need for a resistor to be connected to the generator of the mobile power supply vehicle, etc.

[0095] Furthermore, in the power generation amount estimation device 3 according to the first embodiment, the power generation amount calculation unit 32 calculates the difference Δi multiple times, and calculates an estimate of the power generation amount of the distributed power supply device 50 based on the average value Δia of the multiple differences Δi. This makes it possible to estimate the average value of the power generation amount of the distributed power supply device 50 even if there is some variation in the value of the difference Δi.

[0096] In addition, the power generation amount calculation unit 32 calculates the difference Δiu when there is a transition from a state in which the grid interconnection protective relay 53 of the distributed power supply 50 is not operating to a state in which the grid interconnection protective relay 53 of the distributed power supply 50 is operating, and the difference Δid when there is a transition from a state in which the grid interconnection protective relay 53 of the distributed power supply 50 is operating to a state in which the grid interconnection protective relay 53 of the distributed power supply 50 is not operating, and calculates the average value Δia of the difference Δiu and the difference Δid. Moreover, according to this, the two differences Δi can be efficiently calculated during one cycle from the execution to the stop of the power generation amount estimation process.

[0097] Furthermore, in the power generation amount estimation device 3 according to the first embodiment, when the variation in the calculated differences Δi exceeds an allowable value, the control unit 30 stops the power generation amount estimation process and resumes the power generation amount estimation process after a predetermined period of time has elapsed. When the difference Δi varies greatly, the amount of power generated by the distributed power supply device 50 may not be stable due to sunlight conditions, etc., and an accurate amount of power generation may not be estimated. In such a case, the amount of power generation can be estimated more accurately by temporarily stopping the power generation amount estimation process and resuming the process after a predetermined period of time has elapsed.

[0098] Second Embodiment FIG. 5 is a diagram showing a specific configuration of a mobile power supply vehicle 2 and a power generation amount estimation device 3A in a power supply system 1A according to the second embodiment.

[0099] The power generation amount estimation device 3A of embodiment 2 differs from the power generation amount estimation device 3 of embodiment 1 in that it has a function of estimating the power generation amount of a solar power generation device as a distributed power generation device 50 based on the amount of solar radiation, but is similar to the power generation amount estimation device 3A in other respects.

[0100] As shown in FIG. 5, the power supply system 1A includes an actinometer 6 that measures the amount of solar radiation, and the power generation amount estimation device 3A includes an solar radiation amount acquisition unit 33.

[0101] The solar radiation amount acquiring unit 33 acquires the measurement value of the solar radiation amount measured by the actinometer 6. The solar radiation amount acquiring unit 33 is realized by program processing of the above-mentioned information processing device, similarly to the control unit 30A, the current value acquiring unit 31, and the power generation amount calculating unit 32A, for example.

[0102] The solar radiation acquisition unit 33 is not limited to acquiring solar radiation data from the actinometer 6 in the power supply system 1A. For example, the solar radiation acquisition unit 33 may acquire solar radiation data from an external server via a network such as the Internet, or may acquire solar radiation data input by a user operating an input device (e.g., a keyboard) of the power generation estimation device 3.

[0103] FIG. 6 is a diagram for explaining the relationship between the amount of power generated by a photovoltaic power generation device as the distributed power supply device 50 and the amount of solar radiation.

[0104] In FIG. 6, the horizontal axis represents the amount of power generation, and the vertical axis represents the amount of solar radiation. It is generally known that the amount of power generated by a solar power generation device is approximately proportional to the amount of solar radiation, as shown by reference numeral 401 in Fig. 6. Therefore, for example, if the amount of solar radiation h1 and the amount of power generation P1 at a certain time are known, the amount of power generation (estimated value) Px at the amount of solar radiation hx can be calculated from the correlation (ratio) between the amount of solar radiation h1 and the amount of power generation P1.

[0105] Therefore, in the power generation amount estimation device 3A of embodiment 2, the power generation amount calculation unit 32A calculates an estimated value of the power generation amount from the measured value of the solar radiation based on the correlation (ratio) between the estimated value of the power generation amount calculated by the same power generation amount estimation process as in the power generation amount estimation device 3 of embodiment 1 and the measured value of the solar radiation at that time.

[0106] FIG. 7 is a flowchart showing a process flow for estimating the amount of power generation from the amount of solar radiation performed by the power generation amount estimation device 3A according to the second embodiment.

[0107] In the power generation amount estimation device 3A, first, the control unit 30A controls the solar radiation amount acquisition unit 33 to acquire a measured value of the solar radiation amount (step S21). For example, the solar radiation amount acquisition unit 33 acquires a measured value of the solar radiation amount measured by the actinometer 6.

[0108] Next, the control unit 30A executes a power generation amount estimation process (step S22). Specifically, the control unit 30A controls the current value acquisition unit 31, the power generation amount calculation unit 32A, and the mobile power supply vehicle 2 to execute the process (steps S1 to S12) shown in FIG. 4, thereby calculating an estimate of the power generation amount of the distributed power supply device 50.

[0109] Next, the control unit 30A stores a pair of measurement values, which is a set of the measurement value (h1) of the amount of solar radiation acquired in step S21 and the estimated amount of power generation (P1) calculated in step S22 (step S23).

[0110] Thereafter, the control unit 30A waits for an instruction to estimate the next power generation amount (step S24). For example, when the user operates the power generation estimation device 3A to instruct execution of power generation estimation (step S24: YES), the control unit 30A controls the solar radiation acquisition unit 33 to acquire the measured solar radiation value hx from the actinometer 6 (step S25).

[0111] Next, the control unit 30A controls the power generation amount calculation unit 32A to estimate the power generation amount Px from the measured value hx of the amount of solar radiation acquired in step S25 using the correlation between the amount of solar radiation and the amount of power generation based on the measurement value pair stored in step S23 (step S26). Specifically, as shown in Fig. 6, the estimated value Px of the power generation amount is calculated from the measured value hx of the amount of solar radiation acquired in step S25 based on the ratio between the amount of solar radiation and the amount of power generation based on the measurement value pair (h1, P1).

[0112] As described above, the power generation amount estimation device 3A according to embodiment 2 calculates an estimated value of the power generation amount from the measured value of the solar radiation based on the correlation between the estimated value of the power generation amount calculated by the same power generation amount estimation process as that of the power generation amount estimation device 3 according to embodiment 1 and the measured value of the solar radiation at that time.

[0113] According to this, once an estimated value of the power generation amount of the distributed power supply device 50 is calculated by the power generation amount estimation process, the power generation amount can be estimated from the measured value of the amount of solar radiation without executing the power generation amount estimation process from the next time. As a result, since it is not necessary to execute control for operating the grid interconnection protective relay 53 of the distributed power supply device 50 (control for stopping the supply of power from the distributed power supply device 50 to the power supply path 4 and the consumer load 51) every time in order to estimate the power generation amount, it is possible to estimate the power generation amount more easily and realize a more stable power supply.

[0114] <<Extension of the embodiment>> The invention made by the present inventors has been specifically described above based on an embodiment, but it goes without saying that the invention is not limited thereto and can be modified in various ways without departing from the spirit of the invention.

[0115] For example, in the above embodiment, as an example of calculating the difference Δi multiple times, the difference Δiu when the distributed power supply device 50 transitions from a state in which the grid interconnection protective relay 53 is not operating to a state in which the grid interconnection protective relay 53 is operating, and the difference Δid when the distributed power supply device 50 transitions from a state in which the grid interconnection protective relay 53 is operating to a state in which the grid interconnection protective relay 53 is not operating are calculated, but this is not limiting. For example, the difference Δiu may be calculated multiple times at different times, or the difference Δid may be calculated multiple times.

[0116] In the above embodiment, the case where the amount of power generated by the distributed power supply device 50 is calculated based on the average value Δia of the multiple differences Δi has been exemplified, but this is not limiting. For example, the power generation amount calculation unit 32, 32A may calculate the difference Δi only once, and calculate the amount of power generated by the distributed power supply device 50 based on the calculated one difference Δi.

[0117] In the above embodiment, the control unit 30, 30A may start the power generation amount estimation process at a preset time. For example, by executing the power generation amount estimation process in a time period when the amount of solar radiation is the highest (e.g., noon), the maximum power generation amount of the distributed power supply device 50 in a day can be estimated. This makes it possible to assume that the estimated power generation amount will not be exceeded in other time periods in a day, and therefore enables the manager or the like to easily estimate a time period when measures to prevent reverse power flow are necessary.

[0118] In addition, in the above embodiment, a case has been described in which the power transmission device is a mobile power supply vehicle 2, but the power transmission device may be any device capable of supplying power to consumer equipment 5_1 to 5_n, and is not limited to the mobile power supply vehicle 2.

[0119] In addition, the above-mentioned flowchart shows an example for explaining the operation, and is not limited to this. That is, the steps shown in each figure of the flowchart are specific examples, and are not limited to this flow. For example, the order of some processes may be changed, other processes may be inserted between each process, and some processes may be performed in parallel. [Explanation of symbols]

[0120] 1...power supply system, 2...mobile power supply vehicle, 3,3A...power generation estimation device, 4...power supply path, 5_1 to 5_n...consumer equipment, 6...radiometer, 20...power generation control device, 21...prime mover, 22...generator, 23...circuit breaker, 30,30A...control unit, 31...current value acquisition unit, 32,32A...power generation calculation unit, 33...radiation acquisition unit, 50...distributed power supply unit, 51...consumer load, 52...PCS, 53...grid-connection protective relay, Sd...indication signal.

Claims

1. In a power supply path connecting a device on the power transmission side and a device on the power receiving side including a distributed power supply device having a grid interconnection protective relay, the amount of power generated by the distributed power supply device is estimated based on the difference between a measurement value of a current flowing from the power transmission side to the power receiving side when the grid interconnection protective relay of the distributed power supply device is not operating and a measurement value of the current when the grid interconnection protective relay of the distributed power supply device is operating. Power generation estimation device.

2. The power generation amount estimation device according to claim 1, A current value acquisition unit that acquires a measurement value of the current; a power generation amount calculation unit that calculates an estimated value of a power generation amount of the distributed power supply device connected to the power supply path based on the measurement value of the current acquired by the current value acquisition unit; a control unit that outputs an instruction signal to a device on a power transmission side for instructing whether or not to operate the grid interconnection protective relay of the distributed power supply device, and controls the current value acquisition unit and the power generation amount calculation unit, thereby executing a power generation amount estimation process for estimating a power generation amount of the distributed power supply device, The power generation amount calculation unit, in the power generation amount estimation process, calculates an estimate of the power generation amount of the distributed power supply device based on a difference between a measurement value of the current when the grid interconnection protective relay of the distributed power supply device is not operating and a measurement value of the current when the grid interconnection protective relay of the distributed power supply device is operating, and a voltage value of the power supply path. Power generation estimation device.

3. The power generation amount estimation device according to claim 2, The power generation amount calculation unit calculates the difference a plurality of times, and calculates an estimate of the power generation amount of the distributed power supply device based on an average value of the plurality of differences. Power generation estimation device.

4. The power generation amount estimation device according to claim 3, The power generation amount calculation unit calculates the difference when a transition occurs from a state in which the grid interconnection protective relay of the distributed power supply device is not operating to a state in which the grid interconnection protective relay of the distributed power supply device is operating, and the difference when a transition occurs from a state in which the grid interconnection protective relay of the distributed power supply device is operating to a state in which the grid interconnection protective relay of the distributed power supply device is not operating. Power generation estimation device.

5. The power generation amount estimation device according to claim 4, When the variation of the calculated differences exceeds a tolerance, the control unit stops the power generation amount estimation process and resumes the power generation amount estimation process after a predetermined period of time has elapsed. Power generation estimation device.

6. The power generation amount estimation device according to any one of claims 2 to 5, The control unit starts the power generation amount estimation process at a preset time. Power generation estimation device.

7. The power generation amount estimation device according to any one of claims 2 to 6, Further comprising a solar radiation amount acquisition unit that acquires a measured value of the solar radiation amount, The distributed power supply device is a solar power generation device, The power generation amount calculation unit calculates the estimated value of the power generation amount from the measured value of the amount of solar radiation based on a correlation between the estimated value of the power generation amount calculated by the power generation amount estimation process and the measured value of the amount of solar radiation at that time. Power generation estimation device.

8. The power generation amount estimation device according to any one of claims 2 to 7, a mobile power supply vehicle as the power transmission side device for supplying power to the power supply path, The mobile power supply vehicle operates the grid-connection protective relay of the distributed power supply device in response to the instruction signal. Power supply system.

9. 9. The power supply system according to claim 8, The mobile power supply vehicle changes the voltage supplied to the power supply path to operate the grid-connection protective relay of the distributed power supply device. Power supply system.

10. 9. The power supply system according to claim 8, The mobile power supply vehicle changes the frequency of the voltage supplied to the power supply path to operate the grid-connection protective relay of the distributed power supply device. Power supply system.

11. a first step of measuring a current flowing from a power transmitting side to a power receiving side in a power supply path connecting a power transmitting side device and a power receiving side device including a distributed power supply device having a grid interconnection protective relay when the grid interconnection protective relay of the distributed power supply device is not operating; a second step of measuring the current in a state in which the grid-connection protective relay of the distributed power supply apparatus is not in operation; a third step of calculating a difference between the measurement value of the current acquired in the first step and the measurement value of the current acquired in the second step; and a fourth step of estimating the amount of power generated by the distributed power supply device based on the difference calculated in the third step. Method for estimating power generation.

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