JP6906429B2 - Distributed power system - Google Patents

Description

The present invention is connected to a single-phase three-wire AC line having a first voltage line, a second voltage line, and a neutral line connected to an electric power system at a first connection point with respect to the AC line. The present invention relates to a distributed power supply system including a first power supply device and a power load device connected to a first connection point of an AC line.

When connecting a power supply device such as a fuel cell or a charging / discharging device to the power system, the AC power supply device and the power load device are connected for the purpose of preventing the reverse flow of power from the power supply device to the power system. It is performed to measure how much power is coming and going at a given part of the line. For example, when the power supply device is connected to a single-phase three-wire AC line having a first voltage line, a second voltage line, and a neutral line connected to the power system, a current transformer for an instrument, etc. The electric power is measured at each of the first voltage line and the second voltage line by using the electric power measuring instrument using the above. Then, each power supply device has its own output power based on the total power of the first voltage line and the second voltage line measured by the power measuring instrument so that, for example, a reverse power flow of power to the power system does not occur. To control.

When the power supply device is not provided, only power is supplied from the power system to the power load device, so that the power measured by the first voltage line and the second voltage line is always positive power. On the other hand, when a power supply device is provided, if power is output from the power supply device, the power can be a negative value (reverse power flow) on either the first voltage line or the second voltage line. There is sex. However, each power supply device allows such a state if the total power of the first voltage line and the second voltage line is not a negative value.

If there is an error in the installation of the power measuring instrument, there is a problem that the power cannot be measured accurately. For example, there is a possibility that the positive and negative of the electric power will be measured in reverse, and in that case, it is determined that the reverse power flow to the power system is actually occurring, but the reverse power flow is not occurring. there is a possibility.
Therefore, Patent Document 1 describes a system capable of recognizing that the detection result is incorrect when the detection result of the electric power by the power measuring instrument is incorrect. Specifically, in the system described in Patent Document 1, not only the power in each phase of the AC line to which the power supply device is connected is measured, but also the output from the power supply device to the AC line in at least one phase. It also measures power. As a result, the total value of the supplied power and the load power in each phase can be derived, and if the total value is not 0 W, it can be determined that there is an error in the installation of the power measuring instrument.

In addition, in Patent Document 2, the power supply device measures the power on the first voltage line and the second voltage line while the power supply device is stopped, and either the first voltage line or the second voltage line is in a reverse power flow state. If it is, the configuration is described so that it can be judged as abnormal (there is an error in the installation of the power measuring instrument).

JP 2015-100212 Japanese Patent No. 4484386

In the system described in Patent Document 1, not only a power measuring instrument for measuring the electric power on the AC line to which the power supply device is connected but also a power measuring instrument for measuring the output power from the power supply device to the AC line is required. .. That is, there is a problem that the cost of the system increases.

Further, as described in Patent Document 2, if the power supply device is in a reverse power flow state when either the first voltage line or the second voltage line is in a reverse power flow state while the power supply device is stopped, it is abnormal (power measuring instrument). If the configuration is such that it is judged that there is an error in the installation), and if another power supply device is installed, either the first voltage line or the second voltage line will be installed even if the power measuring instrument is installed correctly. It may also detect reverse power flow conditions in the area. Such an example will be described below.

FIG. 1 is a diagram showing a configuration example of a distributed power supply system. As shown in the figure, this distributed power supply system includes a single-phase three-wire AC line 2 having a first voltage line 2a, a second voltage line 2b, and a neutral line 2c connected to the power system 1. The power generation device 10 connected to the AC line 2 at the second connection point P1, the charging / discharging device 20 connected to the AC line 2 at the first connection point P2, and the first connection point P2 of the AC line 2. The second connection point P1 and the first connection point P2 are provided in the order of arrangement toward the downstream side when viewed from the connection point of the power system 1 with respect to the AC line 2. There is. In FIG. 1, the power toward the downstream side of the AC line 2 is regarded as positive power, that is, the power in the direction from the power system 1 to the second connection point P1 is regarded as positive power, and the power from the second connection point P1 to the second connection point P1 is regarded as positive power. 1 The power in the direction toward the connection point P2 is regarded as positive power.

3 and 4 are diagrams for explaining an operation example of the distributed power supply system as shown in FIG. Specifically, it is an example showing how much power is supplied from the power system 1, the power generation device 10, and the charging / discharging device 20 to the power load device 3. In both cases of FIGS. 3 and 4, the load power of the power load device 3a is 200 W, and the load power of the power load device 3b is 1000 W. That is, the load power of the power load device 3 is 1200 W in total.
In the examples of FIGS. 3 and 4, the power generation device 10 is the first if it is in operation and the total power of the first voltage line 2a and the second voltage line 2b is not in the reverse power flow state. Even if either the voltage line 2a or the second voltage line 2b is in the reverse power flow state, it is not judged to be abnormal. On the other hand, the power generation device 10 is the total of the first voltage line 2a and the second voltage line 2b with respect to the power from the power system 1 side to the second connection point P1 when the output to the AC line 2 is stopped. Even if the power is not in the reverse power flow state, if either the first voltage line 2a or the second voltage line 2b is in the reverse power flow state, it is determined to be abnormal.

FIG. 3 shows an example in which the charging / discharging device 20 outputs a total of 500 W (250 W to each voltage line 2a and 2b) to the AC line 2. In this case, the power from the second connection point P1 side to the first connection point P2 through the first voltage line 2a becomes -50 W, and the first connection is made from the second connection point P1 side through the second voltage line 2b. The power to the location P2 is 750 W. That is, the total power from the second connection point P1 side to the first connection point P2 is 700 W.

In the power generation device 10 during operation, referring to the measurement result of the power measuring instrument 13, the power from the power system 1 side to the second connection point P1 is preferably not negative power and is set to the smallest possible set power. (Especially preferably, the set power is zero, that is, the power from the power system 1 side to the second connection point P1 is zero), and the power provided from the power generation device 10 to the AC line 2 is adjusted. do. In this case, since the power generation device 10 outputs a total of 700 W (350 W to each voltage line 2a and 2b) to the AC line 2, the total power from the power system 1 side to the second connection point P1 is 0 W. (−400W on the first voltage line 2a, 400W on the second voltage line 2b), and the power value is measured by the first measuring instrument 13a and the second measuring instrument 13b.
In this case, the first voltage line 2a has a reverse power flow of 400 W, but the power generation device 10 determines that no abnormality has occurred because it is in operation.

In FIG. 4, the charging / discharging device 20 outputs a total of 500 W (250 W to each voltage line 2a and 2b) to the AC line 2, but the power generation device 10 is stopped (the output to the AC line 2 is stopped). This is an example of the case where. Also in this case, the power from the second connection point P1 side to the first connection point P2 through the first voltage line 2a becomes -50 W, and the first from the second connection point P1 side through the second voltage line 2b. The power going to the connection point P2 is 750 W. That is, the total power from the second connection point P1 side to the first connection point P2 is 700 W.

In the case of the example shown in FIG. 4, since the power generation device 10 is stopped, the total power from the power system 1 side to the second connection point P1 is 700 W (-50 W on the first voltage line 2a, the second voltage). 750W on line 2b). Specifically, the power value on the first voltage line 2a measured by the first measuring instrument 13a is -50 W, and the power value on the second voltage line 2b measured by the second measuring instrument 13b is 750 W. Become. Then, the power generation device 10 determines that the power generation device 10 is abnormal because the reverse power flow state is generated on the first voltage line 2a even though the operation of the power generation device 10 is stopped.

As described above, when the power generation device 10 is included in the distributed power supply system, that is, the power on the first voltage line 2a and the second voltage line 2b is measured even when the power generation device 10 is stopped, and the first voltage thereof is measured. Even if the total power of the line 2a and the second voltage line 2b is not in the reverse power flow state, if either the first voltage line 2a or the second voltage line 2b is in the reverse power flow state, it is determined to be abnormal. When such a power generation device 10 is included in the distributed power supply system, the total power to and from the power system 1 is not in a reverse power flow state, but either the first voltage line 2a or the second voltage line 2b. If is in a reverse current state, a problem that it is judged to be abnormal may occur.

The present invention has been made in view of the above problems, and an object of the present invention is that even if another power supply device is connected to the upstream side of the AC line, the other power supply device causes a reverse power flow state. The point is to provide a distributed power supply system that does not determine that.

The characteristic configuration of the distributed power supply system according to the present invention for achieving the above object is a single-phase three-wire AC having a first voltage line, a second voltage line, and a neutral line connected to a power system. Lines and,
A first power supply unit connected to the AC line at the first connection point,
A distributed power system including a power load device connected to the first connection point of the AC line.
When the power going downstream from the connection point of the power system to the AC line is regarded as positive power,
The first power supply device connects the power from the connection point side of the power system to the AC line to the first connection point through the first voltage line, and to the AC line through the second voltage line. To supply the same power to the first voltage line and the second voltage line so that both the power from the connection point side of the power system to the first connection point does not become negative power. be.
According to the above characteristic configuration, the first power supply device does not supply more power than is consumed by the power load device to the first voltage line and the second voltage line. That is, on the upstream side (power system side) of the first connection point, power is not supplied from the first connection point toward the power system side. Therefore, even if another power supply device is connected to the upstream side of the AC line, the other power supply device does not detect the occurrence of the reverse power flow state due to a factor other than its own operation.
Therefore, even if another power supply device is connected to the upstream side of the AC line, it is possible to provide a distributed power supply system in which the other power supply device does not determine that a reverse power flow state has occurred.

The characteristic configuration of the distributed power supply system according to the present invention for achieving the above object is a single-phase three-wire AC having a first voltage line, a second voltage line, and a neutral line connected to a power system. Lines and,
A first power supply unit connected to the AC line at the first connection point,
A distributed power system including a power load device connected to the first connection point of the AC line.
A second power supply device connected to the AC line at a second connection point is provided.
The second connection point and the first connection point are provided in the order of arrangement toward the downstream side when viewed from the connection point of the power system to the AC line.
When the power going downstream from the connection point of the power system to the AC line is regarded as positive power,
The first power supply device connects the power from the connection point side of the power system to the AC line to the first connection point through the first voltage line, and to the AC line through the second voltage line. Power is supplied to the first voltage line and the second voltage line so that both the power from the connection point side of the power system to the first connection point does not become negative power.
The second power supply device has either the first voltage line or the second voltage line for the power from the power system side to the second connection point when the output to the AC line is stopped. The point is that it is configured to be judged as abnormal if it is in a reverse power flow state.
According to the above characteristic configuration, the first power supply device does not supply more power than is consumed by the power load device to the first voltage line and the second voltage line. That is, on the upstream side (power system side) of the first connection point, power is not supplied from the first connection point toward the power system side. Therefore, even if another power supply device is connected to the upstream side of the AC line, the other power supply device does not detect the occurrence of the reverse power flow state due to a factor other than its own operation.
In addition, as described above, the first power supply device includes the power from the connection point side of the power system to the AC line to the first connection point through the first voltage line and the AC line through the second voltage line. Power is supplied to the first voltage line and the second voltage line so that both the power from the connection point side of the power system to the first connection point to the first connection point does not become negative power. Therefore, when the output of the second power supply device to the AC line is stopped, neither the first voltage line nor the second voltage line is in a reverse power flow state with respect to the power from the power system side to the second connection point. As a result, the second power supply device is not determined to be abnormal.
Therefore, even if another power supply device is connected to the upstream side of the AC line, it is possible to provide a distributed power supply system in which the other power supply device does not determine that a reverse power flow state has occurred.

Yet another characteristic configuration of the distributed power supply system according to the present invention includes a second power supply device connected to the AC line at a second connection point.
The second connection point and the first connection point are provided in the order of arrangement toward the downstream side when viewed from the connection point of the power system to the AC line.
The second power supply device has either the first voltage line or the second voltage line for the power from the power system side to the second connection point when the output to the AC line is stopped. The point is that it is configured to be judged as abnormal if it is in a reverse power flow state.

According to the above-mentioned characteristic configuration, as described above, the first power supply device transmits the power from the connection point side of the power system to the AC line to the first connection point through the first voltage line and the second voltage line. Power is supplied to the first voltage line and the second voltage line so that both the power from the connection point side of the power system to the AC line to the first connection point does not become negative power. Therefore, when the output of the second power supply device to the AC line is stopped, neither the first voltage line nor the second voltage line is in a reverse power flow state with respect to the power from the power system side to the second connection point. As a result, the second power supply device is not determined to be abnormal.

Yet another characteristic configuration of the distributed power supply system according to the present invention is that the second power supply device is connected to the AC line and has a power generation unit and a power generation control unit that controls the operation of the power generation unit.
The first power supply device is connected to the AC line and has a charge / discharge unit for charging / discharging electric power with the AC line and a charge / discharge control unit for controlling the operation of the charge / discharge unit. ..

According to the above characteristic configuration, the second power supply device can adjust the power supplied to the first voltage line and the second voltage line by the power generated by the power generation unit, and the first power supply device has the first voltage line and the first voltage line. The power supplied to the two voltage lines can be adjusted by the power discharged by the charging / discharging unit.

Yet another characteristic configuration of the distributed power supply system according to the present invention is that the power received by the first power supply device from the AC line is the charging power from the AC line by the first power supply device as the positive power received. When the power discharged from the first power supply device to the AC line is regarded as the negative power received,
The power generation control unit of the second power supply device supplies power corresponding to the sum of the power consumption received by the power load device from the AC line and the power received by the first power supply device from the AC line. The power provided from the second power supply device to the AC line is controlled within a range between a predetermined minimum power supply and the maximum power supply so as to be provided from the device to the AC line.
In the charge / discharge control unit of the first power supply device, the sum of the power consumption received by the power load device from the AC line and the received power received by the first power supply device from the AC line becomes a predetermined target power. As described above, the point is that the first power supply device controls the received power received from the AC line.

According to the above characteristic configuration, in the charge / discharge control unit of the first power supply device, the sum of the power consumption received by the power load device from the AC line and the received power received by the first power supply device from the AC line becomes a predetermined target power. The first power supply device controls the received power received from the AC line so as to be. As a result, the power generation control unit of the second power supply device controls the power provided from the second power supply device to the AC line so that the power corresponding to the constant target power is provided from the second power supply device to the AC line. .. That is, the power generation unit of the second power supply device can preferably be operated with a constant output (= target power).

It is a figure which shows the structure of the distributed power supply system. It is a figure which illustrates the operating state of the distributed power supply system. It is a figure which illustrates the operating state of the distributed power supply system. It is a figure which illustrates the operating state of the distributed power supply system.

The distributed power supply system according to the embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram showing a configuration of a distributed power supply system. As shown in FIG. 1, the distributed power supply system includes a single-phase three-wire AC line 2 having a first voltage line 2a, a second voltage line 2b, and a neutral line 2c connected to the power system 1. A charge / discharge device 20 as a first power supply device connected to the AC line 2 at the first connection point P2, and a power load device 3 connected to the first connection point P2 of the AC line 2 are provided. In addition, the distributed power supply system shown in FIG. 1 also includes a power generation device 10 as a second power supply device. The power generation device 10 is connected to the AC line 2 at the second connection point P1. Here, the second connection point P1 and the first connection point P2 are provided in the order of arrangement toward the downstream side when viewed from the connection point of the power system 1 with respect to the AC line 2. When the total of the power supplied by the power generation device 10 to the AC line 2 and the power supplied by the charging / discharging device 20 to the AC line 2 is less than the load power of the power load device 3, the insufficient power is the power received from the power system 1. Covered by.

In the present embodiment, the power going downstream from the connection point of the power system 1 to the AC line 2 is regarded as positive power, that is, the power in the direction from the power system 1 to the second connection point P1 is positive power. The power in the direction from the second connection point P1 to the first connection point P2 is regarded as positive power. Further, as the received power received from the AC line 2 by the charging / discharging device 20, the charging power from the AC line 2 by the charging / discharging device 20 is regarded as a positive received power, and the discharging power to the AC line 2 by the charging / discharging device 20 is negative. The explanation will be given by regarding it as the received power of.

[Power generation device (second power supply device)]
The power generation device 10 is connected to an AC line 2 and has a power generation unit 11 and a power generation control unit 12 that controls the operation of the power generation unit 11. For example, the power generation unit 11 has a fuel cell such as a solid oxide fuel cell (SOFC) or a polymer electrolyte fuel cell (PEFC). Although not shown, the power generation unit 11 has a power conversion unit for converting the generated power into power having a desired voltage, frequency, and phase and outputting the power to the AC line 2. Then, the power generation control unit 12 controls the operation start, operation stop, output, and the like of the power generation unit 11.

Information about the electric power measured by the electric power measuring instrument 13 is transmitted to the power generation control unit 12. The power measuring instrument 13 is provided on the upstream side (power system 1 side) of the second connection point P1 in the middle of the AC line 2, and measures the power from the power system 1 side to the second connection point P1. The power measuring instrument 13 is composed of a first measuring instrument 13a provided on the first voltage line 2a and a second measuring instrument 13b provided on the second voltage line 2b. The first measuring instrument 13a and the second measuring instrument 13b as the power measuring instrument 13 are configured by using, for example, a current transformer (current transformer for instrument) used for detecting the current value of the electric power in the AC line 2. The power value on the AC line 2 can be derived from the product with a predetermined voltage value (for example, 100V, 200V, etc.). The electric power measuring instrument 13 may transmit only the current value of the electric power on the AC line 2 to the power generation control unit 12, and the power generation control unit 12 may derive the electric power value.

The power measured by the power measuring instrument 13 is the sum of the load power received by the power load device 3 from the AC line 2 and the received power received by the charging / discharging device 20 from the AC line 2, and the power is transferred from the power generation device 10 to the AC line 2. Corresponds to the value obtained by subtracting the provided power.

The power generation control unit 12 of the power generation device 10 refers to the measurement result of the power measuring device 13 and sums the load power received by the power load device 3 from the AC line 2 and the received power received by the charging / discharging device 20 from the AC line 2. The power provided from the power generation device 10 to the AC line 2 is controlled within a range between the predetermined minimum provided power and the maximum provided power so that the power corresponding to the above is provided from the power generation device 10 to the AC line 2. For example, in the power generation device 10, the power from the power system 1 side to the second connection point P1 is preferably not negative power and is set as small as possible (particularly preferably, the set power is zero). That is, the power provided from the power generation device 10 to the AC line 2 is adjusted so that the power from the power system 1 side to the second connection point P1 becomes zero).

Further, when the power generation device 10 itself stops outputting to the AC line 2, the power generation device 10 refers to the measurement result of the power measuring instrument 13 and refers to the first voltage for the power from the power system 1 side to the second connection point P1. If either the line 2a or the second voltage line 2b is in a reverse power flow state, it is determined to be abnormal. This is because, for example, it is determined that an abnormality such as an error in the positive or negative of the measured power has occurred due to an error in the installation of the power measuring instrument 13.

[Charging / discharging device (first power supply device)]
The charge / discharge device 20 includes a charge / discharge unit 21 that charges / discharges electric power to / from the AC line 2 and a charge / discharge control unit 22 that controls the operation of the charge / discharge unit 21. The charge / discharge unit 21 has a storage battery such as a secondary battery such as a lithium ion battery. Although not shown, the power generation unit 11 is connected to the AC line 2 via a power conversion unit or the like. As a result, the charge / discharge unit 21 can convert the electric power into electric power having a desired voltage, frequency, and phase and output the electric power to the AC line 2. The charge / discharge control unit 22 controls the operation of the power conversion unit to control the output power (discharge power) from the charge / discharge unit 21 to the AC line 2 and the input power (discharge power) from the AC line 2 to the charge / discharge unit 21. (Charging power) is controlled.

Information about the electric power measured by the electric power measuring instrument 23 is transmitted to the charge / discharge control unit 22. The power measuring instrument 23 is provided between the second connection point P1 and the first connection point P2 in the middle of the AC line 2, and goes from the connection point side of the power system 1 to the AC line 2 toward the first connection point P2. The electric power, particularly the electric power from the second connection point P1 to the first connection point P2 is measured. The power measuring instrument 23 includes a first measuring instrument 23a provided on the first voltage line 2a and a second measuring instrument 23b provided on the second voltage line 2b. That is, the power measured by the power measuring device 23 corresponds to the sum of the load power received by the power load device 3 from the AC line 2 and the received power received by the charging / discharging device 20 from the AC line 2. The power measuring instrument 23 is configured by using, for example, a current transformer (current transformer for measuring instruments) used for detecting the current value of electric power on the AC line 2, and has a predetermined voltage value (for example, 100V, 200V, etc.). From the product, the power value on the AC line 2 can be derived. The electric power measuring instrument 23 may transmit only the current value of the electric power on the AC line 2 to the charge / discharge control unit 22, and the charge / discharge control unit 22 may derive the electric power value.

Then, the charge / discharge control unit 22 refers to the measurement result of the power measuring device 23 and receives the received power (charge power from the AC line 2 or discharge power to the AC line 2) received by the charge / discharge device 20 from the AC line 2. To control. For example, the charge / discharge control unit 22 charges / discharge device so that the sum of the load power received by the power load device 3 from the AC line 2 and the received power received by the charge / discharge device 20 from the AC line 2 approaches a predetermined target power. 20 controls the received power received from the AC line 2. This target power is set to a value equal to, for example, the maximum power provided by the power generation device 10 (for example, 700 W).

When the charging / discharging device 20 performs such control, the power generation control unit 12 of the power generation device 10 ACs from the power generation device 10 so as to provide the power corresponding to the target power from the power generation device 10 to the AC line 2. Controls the power provided to line 2. That is, the power generation device 10 can preferably be operated with a constant output (= target power).

FIG. 2 is a diagram illustrating an operating state of a distributed power supply system. Specifically, it is an example showing how much power is supplied from the power system 1, the power generation device 10, and the charging / discharging device 20 to the power load device 3. In this example, the load power of the power load device 3a is 200 W, and the load power of the power load device 3b is 1000 W. That is, the load power of the power load device 3 is 1200 W in total.
In the example of FIG. 2, if the power generation device 10 is in operation, the power generation device 10 refers to the power value measured by the power measuring instrument 13 and refers to the power from the power system 1 side to the second connection point P1. If the total power of the first voltage line 2a and the second voltage line 2b is not in the reverse power flow state, even if either the first voltage line 2a or the second voltage line 2b is in the reverse power flow state, it is abnormal. Do not judge. On the other hand, the power generation device 10 is the total of the first voltage line 2a and the second voltage line 2b with respect to the power from the power system 1 side to the second connection point P1 when the output to the AC line 2 is stopped. Even if the power is not in the reverse power flow state, if either the first voltage line 2a or the second voltage line 2b is in the reverse power flow state, it is determined to be abnormal.

The charging / discharging device 20 passes through the first voltage line 2a and goes from the connection point side of the power system 1 to the AC line 2 to the first connection point P2 (particularly, from the second connection point P1 side to the first connection point P2). Power going to) and power going from the connection point side of the power system 1 to the AC line 2 to the first connection point P2 through the second voltage line 2b (particularly, from the second connection point P1 side to the first connection point P2). Power is supplied to the first voltage line 2a and the second voltage line 2b so that both of the heading powers) do not become negative powers. That is, the load power of the power load device 3a connected to the first voltage line 2a is 200 W, and the load power of the power load device 3b connected to the second voltage line 2b is 1000 W, so that the first voltage line 2a What is negative power for both the power from the second connection point P1 side to the first connection point P2 and the power from the second connection point P1 side to the first connection point P2 through the second voltage line 2b? In order to prevent this, the charging / discharging device 20 may output 200 W of electric power (400 W in total) to the first voltage line 2a and the second voltage line 2b. As described above, in the present embodiment, the charging / discharging device 20 supplies the same electric power to the first voltage line 2a and the second voltage line 2b.

As a result, in the case of the example shown in FIG. 2, the power from the second connection point P1 side to the first connection point P2 through the first voltage line 2a becomes 0 W, and the second connection is made through the second voltage line 2b. The power from the point P1 side to the first connection point P2 is 800 W. That is, the total power from the second connection point P1 side to the first connection point P2 is 800 W. Then, the sum of the load power received by the power load device 3 from the AC line 2 and the received power received by the charging / discharging device 20 from the AC line 2 approaches a predetermined target power (for example, 700 W).

In the example shown in FIG. 2, since the power generation device 10 is stopped (the output to the AC line 2 is stopped), the power generation device 10 does not supply power to the AC line 2, but the power generation device 10 Measures the power on the first voltage line 2a and the second voltage line 2b even while its own operation is stopped, and if either the first voltage line 2a or the second voltage line 2b is in a reverse power flow state. Judge as abnormal.

Then, 800 W, which is the total power from the second connection point P1 side to the first connection point P2, is covered by the power received from the power system 1. That is, the power from the power system 1 to the second connection point P1 through the first voltage line 2a, which is the monitoring target of the power generation device 10, that is, the power measured by the first measuring instrument 13a becomes 0 W, and the power generation device The power from the power system 1 side to the second connection point P1 through the second voltage line 2b, which is the monitoring target of 10, that is, the power measured by the second measuring instrument 13b is 800 W. Therefore, the power from the power system 1 to the second connection point P1 through the first voltage line 2a and the second connection from the power system 1 side through the second voltage line 2b, which the power generation device 10 monitors. Neither of the powers going to point P1 is in a reverse power flow state. Therefore, the power generation device 10 does not determine that the reverse power flow state has occurred.

As described above, in the distributed power supply system of the present embodiment, the charging / discharging device 20 does not supply more power than the power load device 3 consumes to the first voltage line 2a and the second voltage line 2b. .. That is, on the upstream side (power system 1 side) of the first connection point P2, power is not supplied from the first connection point P2 toward the second connection point P1 side. Therefore, the power generation device 10 does not detect the occurrence of the reverse power flow state due to factors other than its own operation. Therefore, it is possible to provide a distributed power supply system in which the power generation device 10 connected to the upstream side of the AC line 2 does not determine that the reverse power flow state has occurred.

<Another Embodiment>
<1>
In the above embodiment, the configuration of the distributed power supply system of the present invention has been described with reference to specific examples, but the configuration can be changed as appropriate.
For example, in the above embodiment, the example in which the power generation device is adopted as the second power supply device and the charge / discharge device is adopted as the first power supply device has been described, but the charge / discharge device is adopted as the second power supply device and the first power supply is used. A power generation device may be adopted as the device.
Further, the configurations of the power generation device (second power supply device) 10 and the charge / discharge device (first power supply device) 20 are not limited to those shown in the drawings and can be changed as appropriate. For example, in the above embodiment, the fuel cell is mentioned as an example of the power generation unit 11 included in the power generation device 10, but there are various other types in which the output can be freely adjusted within a range between a predetermined minimum provided power and a maximum provided power. Power generation unit 11 can be used. For example, a power generation unit 11 of a type including an engine and a generator driven by the engine can be used.

<2>
In the above embodiment, each of the power generation device (second power supply device) 10 and the charge / discharge device (first power supply device) 20 supplies the same power to the first voltage line 2a and the second voltage line 2b. However, different powers may be supplied to the first voltage line 2a and the second voltage line 2b. For example, if a power conversion unit that adjusts the power supplied to the first voltage line 2a and a power conversion unit that adjusts the power supplied to the second voltage line 2b are separately provided, the first voltage Different powers can be supplied to the line 2a and the second voltage line 2b.

<3>
The configurations disclosed in the above embodiment (including other embodiments, the same shall apply hereinafter) can be applied in combination with the configurations disclosed in other embodiments as long as there is no contradiction, and are disclosed in the present specification. The embodiment is an example, and the embodiment of the present invention is not limited to this, and can be appropriately modified without departing from the object of the present invention.

The present invention can be used in a distributed power supply system in which even if another power supply device is connected to the upstream side of the AC line, the other power supply device does not determine that a reverse power flow state has occurred.

1 Power system 2 AC line 2a 1st voltage line 2b 2nd voltage line 3 Power load device 10 Power generation device (2nd power supply device)
11 Power generation unit 12 Power generation control unit 13 Power measuring instrument 20 Charging / discharging device (first power supply device)
21 Charging / discharging unit 22 Charging / discharging control unit P1 Second connection point P2 First connection point

Claims (5)

A single-phase three-wire AC line having a first voltage line, a second voltage line, and a neutral line connected to the power system,
A first power supply unit connected to the AC line at the first connection point,
A distributed power system including a power load device connected to the first connection point of the AC line.
When the power going downstream from the connection point of the power system to the AC line is regarded as positive power,
The first power supply device connects the power from the connection point side of the power system to the AC line to the first connection point through the first voltage line, and to the AC line through the second voltage line. A distributed type that supplies the same power to the first voltage line and the second voltage line so that both the power from the connection point side of the power system to the first connection point does not become negative power. Power system. A second power supply device connected to the AC line at a second connection point is provided.
The second connection point and the first connection point are provided in the order of arrangement toward the downstream side when viewed from the connection point of the power system to the AC line.
The second power supply device has either the first voltage line or the second voltage line for the power from the power system side to the second connection point when the output to the AC line is stopped. The distributed power supply system according to claim 1, wherein it is determined to be abnormal if it is in a reverse power flow state. A single-phase three-wire AC line having a first voltage line, a second voltage line, and a neutral line connected to the power system,
A first power supply unit connected to the AC line at the first connection point,
A distributed power system including a power load device connected to the first connection point of the AC line.
A second power supply device connected to the AC line at a second connection point is provided.
The second connection point and the first connection point are provided in the order of arrangement toward the downstream side when viewed from the connection point of the power system to the AC line.
When the power going downstream from the connection point of the power system to the AC line is regarded as positive power,
The first power supply device connects the power from the connection point side of the power system to the AC line to the first connection point through the first voltage line, and to the AC line through the second voltage line. Power is supplied to the first voltage line and the second voltage line so that both the power from the connection point side of the power system to the first connection point does not become negative power.
The second power supply device has either the first voltage line or the second voltage line for the power from the power system side to the second connection point when the output to the AC line is stopped. distributed-type power system that is configured to determine that an abnormality if reversed power flow state. The second power supply device is connected to the AC line and has a power generation unit and a power generation control unit that controls the operation of the power generation unit.
It said first power supply, connected to said AC line, according to claim 2 having a discharge control unit for controlling the charging and discharging discharge portion and the operation of the charging and discharging unit which performs the power between the AC line Or the distributed power supply system according to 3. As the received power received from the AC line by the first power supply device, the charging power from the AC line by the first power supply device is regarded as a positive received power, and the discharge power to the AC line by the first power supply device is used. When considered as negative power received
The power generation control unit of the second power supply device supplies power corresponding to the sum of the power consumption received by the power load device from the AC line and the power received by the first power supply device from the AC line. The power provided from the second power supply device to the AC line is controlled within a range between a predetermined minimum power supply and the maximum power supply so as to be provided from the device to the AC line.
In the charge / discharge control unit of the first power supply device, the sum of the power consumption received by the power load device from the AC line and the received power received by the first power supply device from the AC line becomes a predetermined target power. The distributed power supply system according to claim 4, wherein the first power supply device controls the received power received from the AC line.

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