JP7318856B2 - Switching device and electric power system provided with the switching device - Google Patents

Description

The present invention includes a switching device that switches between an energized state in which a power device is receiving or transmitting power from a power system and a disconnected state in which it is not receiving or transmitting power, and the switching device. Regarding power systems.

2. Description of the Related Art In recent years, an electric power system that manages a plurality of electric power devices connected to an electric power system and controls electric power transmitted and received to and from the electric power system has become widespread. For example, Patent Literature 1 discloses an example of a power system that includes a centralized control device and a plurality of power devices and controls output power by an autonomous distributed cooperative control method. The centralized management device calculates a guide index for controlling the output power of the entire power system to the target power. The plurality of power devices use the common guide index calculated by the central control device to calculate the target value of the output power of the device based on the optimization problem set for each device. Then, the output power of the own device is controlled so that the output power reaches the target value. Each power device autonomously controls the output power based on the induction index, so that the output power of the entire power system is controlled to the target power. Since the centralized control device only calculates and transmits the index without grasping the state of each power device, the burden of computation and communication is small. Therefore, a high-performance and expensive centralized control device is not required, and the initial installation cost can be reduced. Also, when expanding the electric power system, no major modification of the central control device is required.

JP 2018-148627 A

In Patent Document 1, as power devices, a photovoltaic power generation device capable of controlling output power and a power storage device capable of being charged and discharged and capable of controlling input/output power are assumed. The centralized management device cannot include power devices whose input/output power cannot be controlled as objects of management.

The present invention has been conceived under the circumstances described above, and provides a power system capable of expanding the management target of a centralized control device to include power devices whose input/output power cannot be controlled, and a switching system used in the power system. The purpose is to provide an apparatus.

A switching device provided by the first aspect of the present invention switches between an energized state in which a power device is receiving or transmitting power from a power system and a disconnected state in which it is neither receiving nor transmitting power. A switching device, in which the power device is placed in the energized state or the non-connected state based on a guidance index input from a centralized control device that manages the switching device and a preset optimization problem. and a comparison unit for switching between the energized state and the disconnected state based on a comparison result of comparing the judgment index with a predetermined value. Characterized by

In a preferred embodiment of the present invention, a switch is arranged on a connection line that connects the power device and the power system, and switches between a state in which the power device is connected to the power system and a state in which the power device is disconnected from the power system. and wherein the comparison unit instructs switching of the switch based on the comparison result.

The determination index calculation unit sets the guidance index to pr, the maximum value of the guidance index to pr ^lmt , _a2 as a parameter based on priority, and _a1 and _a3 as arbitrary parameters, X , the determination index is calculated.

The comparison unit does not switch between the energized state and the disconnected state when the determination index is within a predetermined range based on the predetermined value.

The comparison unit includes a time measuring means for measuring the time during which the unconnected state continues, and a lottery means for performing a lottery when the time measured by the time measuring means exceeds a predetermined time, and a lottery is won by the lottery means. case, switching to the energized state regardless of the comparison result.

The power system provided by the second aspect of the present invention includes a plurality of switching devices provided by the first aspect of the present invention, and the centralized control device that outputs the common guidance indicator to each of the switching devices. and

According to the present invention, the judgment index calculation unit calculates the judgment index based on the common guidance index input from the centralized control device and the preset optimization problem. Then, the comparison unit switches between the energized state and the non-connected state based on the comparison result of comparing the judgment index with the predetermined value. That is, the switching device autonomously turns on and off power transmission and reception of the power device based on the induction index. Therefore, the centralized control device can make the power device, which cannot control the input/output power, perform on/off control based on the induction index. As a result, in the power system, it is possible to expand the objects managed by the centralized management device to include power devices whose input/output power cannot be controlled.

It is a block diagram showing the whole electric power system composition concerning a 1st embodiment. FIG. 4 is a characteristic diagram showing change characteristics of a judgment index with respect to a guidance index; FIG. 8 is a block diagram showing the internal configuration of a switching device according to the second embodiment; It is a time chart which shows the time change of each value in simulation, (a) is a case where lottery processing is not performed, (b) is a case where lottery processing is performed. 9 is a flowchart for explaining lottery processing performed by a comparison unit; FIG. 12 is a block diagram showing the internal configuration of a switching device according to the third embodiment;

Preferred embodiments of the present invention will now be specifically described with reference to the accompanying drawings.

FIG. 1 is a block diagram showing the overall configuration of a power system according to the first embodiment. The power system G is interconnected with the power system E, and can transmit and receive power from the power system E. The power system G controls the output power by the autonomous distributed cooperative control method so that the power at the connection point between the power system G and the power system E (hereinafter referred to as "connection point power") becomes the target power. In the following description, when the power system G transmits power to the power system E (reverse power flow), the connection point power is assumed to be a positive value. On the other hand, when the power system G receives power from the power system E, the connection point power is a negative value. The electric power system G includes a centralized control device F, power conditioners C1 to Cn, power conditioners D1 to Dm, and switching devices A1 to Ak.

The centralized control device F monitors the connection point power and calculates an index for instantaneous value control of the connection point power to the target power. In this embodiment, the central control device F uses the power value detected at the connection point between the power system G and the power system E as the connection point power P(t). The central control device F receives the output power detection values detected by each of the power conditioners C1 to Cn and D1 to Dm and each of the switching devices A1 to Ak, and calculates from these detection values An estimated value may be used as the connection point power P(t). The central control device F calculates the induction index pr based on the difference between the set target power P ^c and the connection point power P(t), and the power conditioners C1 to Cn, D1 to Dm and each switching A common guiding index pr is transmitted to the devices A1 to Ak. Note that the communication method is not limited, and may be wired communication or wireless communication.

Each of the power conditioners C1 to Cn is connected to a solar cell, converts DC power generated by the solar cell into AC power, and outputs the AC power. Each of the power conditioners C1 to Cn has a target power calculator 91 and an output controller 92 . The target power calculation unit 91 uses the induction index pr received from the central control device F to calculate a target power value P ^ref that is the target value of the output power of the own device based on a preset optimization problem. do. The output control section 92 controls the output power based on the target power value P ^ref calculated by the target power calculation section 91 .

Each of the power conditioners D1 to Dm is connected to a storage battery, and charges and discharges the storage battery. Although omitted in FIG. 1, each of the power conditioners D1 to Dm includes a target power calculator 91 and an output controller 92, like the power conditioners C1 to Cn. An optimization problem suitable for charging/discharging the storage battery is set in advance in the target power calculation unit 91 of the power conditioners D1 to Dm.

The switching devices A1 to Ak are connected to the power devices B1 to Bk, respectively, and switch between a state in which the power devices B1 to Bk are connected to the power system E and a state in which they are disconnected. Each power device B1 to Bk is a load that consumes power or a power generation facility that supplies power. Each of the power devices B1 to Bk is a relatively small-scale facility and cannot control the power it consumes and the power it supplies. Examples of power-consuming loads include industrial and household loads whose power consumption cannot be adjusted, and small-scale EV charging facilities. A small-scale EV charging facility cannot control the amount of charge to a connected EV vehicle. Examples of power generation facilities that supply electric power include small-scale photovoltaic devices for home use and the like. In the following description, the switching devices A1 to Ak will be referred to as "switching device A" when they are not distinguished from each other. Also, when the power devices B1 to Bk are described without distinction, they will be referred to as "power device B." Each switching device A switches to a state in which the connected power device B is interconnected with the power system E, thereby switching to an energized state in which the power device B receives (or transmits) power. On the other hand, each switching device A switches to a state in which the connected power device B is disconnected from the power system E, thereby switching to a disconnected state in which the power device B does not receive (or transmit) power. Based on the guidance index pr received from the central control device F, the switching device A switches between interconnection and disconnection of the connected power device B. FIG. Details of the switching device A will be described later.

Each power conditioner C1-Cn, D1-Dm autonomously controls the input/output power based on the common induction index pr received from the central control device F, and each switching device A1-Ak controls the common induction index By autonomously switching between the energized state and the disconnected state based on pr, the output power (connection point power P(t)) of the entire power system G is controlled to the target power ^Pc . In this embodiment, the central control device F increases the induction index pr when the connection point power P(t) is greater than the target power ^Pc , and increases the induction index pr when the connection point power P(t) is less than the target power ^Pc . to reduce the guidance index pr. Each of the power conditioners C1 to Cn, D1 to Dm and each of the switching devices A1 to Ak operates to reduce the connection point power P(t) as the induction index pr received from the centralized control device F increases. The smaller the index pr, the larger the connection point power P(t). Detailed descriptions of the power conditioners C1 to Cn, D1 to Dm and the central control device F are omitted.

Next, the details of the switching device A will be described. The switching device A includes a determination section 11 and a switch 12 . Using the guidance index pr received from the central control device F, the determination unit 11 connects the power device B to the power system E or disconnects it from the power system E based on a preset optimization problem. decide whether to let The judgment unit 11 outputs the judgment result to the switch 12 . The determination unit 11 includes a determination index calculation unit 111 and a comparison unit 112 .

The determination index calculation unit 111 uses the guidance index pr received from the central control device F to determine whether to connect or disconnect the power device B based on a preset optimization problem. A judgment index X is calculated. This optimization problem contains an evaluation function.

The determination index calculator 111 is set with an arithmetic expression shown by the following formula (1) derived from the set evaluation function, and calculates the determination index X by this arithmetic expression. The index limit pr ^lmt is a value that defines the maximum and minimum values of the guidance index pr calculated by the central control device F. a ₁ , a ₂ , and a ₃ are setting parameters, which are set according to the characteristics of the power equipment B, the order of priority, and the like. The parameter a ₁ is mainly a value for adjusting the amount of change in the judgment index X according to the change in the guidance index pr, and is set to a value greater than zero. Parameter _a2 is primarily a value that sets the priority. A value of -1 or more and 1 or less is set for the parameter _a2 . The parameter _a3 is mainly a value that adjusts the guidance index pr at which the judgment index X begins to change. In this embodiment, "1" is set for parameter _a1 and parameter _a3 . Note that parameter a ₁ and parameter a ₃ are not limited. Also, the parameters a ₁ and a ₃ may be set to different values depending on whether the guidance index pr is a positive value or a negative value. The judgment index calculation unit 111 outputs the calculated judgment index X to the comparison unit 112 . It should be noted that the determination index calculation unit 111 may calculate the determination index X by solving a set evaluation function instead of the arithmetic expression shown in Equation (1) below.

FIG. 2 is a characteristic diagram showing the change characteristics of the judgment index X with respect to the guidance index pr when "1" is set for the parameters _a1 and _a3 and "0" is set for the parameter _a2 ( See solid line). In the figure, the horizontal axis is the guidance index pr, and the vertical axis is the judgment index X. As shown in FIG. As shown in the figure, the change characteristic of the judgment index X is proportional to the guidance index pr, and the larger the guidance index pr, the smaller it becomes, and becomes "0" when the guidance index pr is "0". Further, it is "-1" when the induction index pr is the maximum value pr ^lmt , and is "1" when the induction index pr is the minimum value (-pr ^lmt ). Note that each setting value set in the determination index calculation unit 111 is not limited, and may be set as appropriate according to the characteristics and priority of the power device B connected to the switching device A.

The order of priority of the power device B (the order in which it should be connected to the power system E) is appropriately set according to the characteristics of the power device B, such as its rated capacity and design life. What is prioritized differs depending on the design concept, environment, state, etc. of the power system G. Also, the designer can arbitrarily set the priority according to the importance of the power device B to be connected. In the present embodiment, the parameter _a2 is set to a value according to the priority that comprehensively considers the characteristics and importance of the power equipment B. FIG. The power device B has a load that consumes power and a power generation facility that supplies power. Among the loads, power unit B, a priority is set. In this case, the higher the priority, the smaller value is set to the parameter _a2 . Also, a priority is set in the power equipment B, which is a power generation facility. In this case, the higher the priority, the larger the value set to the parameter _a2 . As the parameter _a2 is set to a smaller value, the judgment index X when the guidance index pr is "0" becomes smaller, and the straight line indicating the change characteristic of the judgment index X in FIG. 2 moves downward in the drawing.

Note that the priority according to the characteristics of the power device B and the priority according to the importance of the power device B may be set to different parameters. For example, the priority according to the importance of the power equipment B may be set to the parameter _a2 , and the priority according to the characteristics of the power equipment B may be set to the parameter _a1 . In this case, when a ₂ <0, the higher the priority, the smaller the parameter a ₁ is set to the power device B, which is the load. On the other hand, when a ₂ >0, the higher the priority, the larger the value set to the parameter a ₁ . In addition, in the power device B, which is a power generation facility, when a ₂ <0, the higher the priority, the larger the value set to the parameter a ₁ . On the other hand, when a ₂ >0, the higher the priority, the smaller the value set for the parameter a ₁ . As the parameter a ₁ is set to a smaller value, the slope of the straight line indicating the change characteristic of the judgment index X in FIG. 2 becomes gentler.

The comparison unit 112 compares the determination index X input from the determination index calculation unit 111 with a predetermined value to determine whether the power device B should be interconnected with the power system E or disconnected from the power system E. . The comparison unit 112 outputs the determination result to the switch 12 . When the connected power device B is a load that consumes power, the comparison unit 112 determines that the determination index X is to be connected if it is equal to or less than a predetermined value, and that it is to be disconnected if it is greater than the predetermined value. Further, when the connected power device B is a power generation facility that supplies power, the comparison unit 112 determines that if the determination index X is equal to or less than a predetermined value, it should be disconnected, and if it is greater than a predetermined value, it should be connected. . In this embodiment, the predetermined value for comparison is "0". Note that the predetermined value is not limited.

The switch 12 is arranged on a connection line that connects the power device B and the power system E. The power device B is connected to the power system E and the power device B is disconnected from the power system E. It is a switch that switches between The switch 12 performs switching based on the determination result input from the comparator 112 .

As is clear from the above formula (1), the judgment index X is proportional to the guidance index pr, and decreases as the guidance index pr increases (see FIG. 2). Therefore, when the power device B is the load, the larger the induction index pr, the smaller the determination index X, and when it falls below a predetermined value, the power device B is switched from the parallel state to the connected state. This increases the power consumption and reduces the connection point power P(t). On the other hand, when the induction index pr becomes smaller, the determination index X becomes larger and exceeds a predetermined value, whereby the power device B is switched from the connected state to the parallel-off state. This reduces the power consumption and increases the connection point power P(t). Further, when the power device B is a power generation facility, when the induction index pr increases, the determination index X decreases and falls below a predetermined value, whereby the power device B is switched from the connected state to the parallel-off state. As a result, the power supplied is reduced and the connection point power P(t) is reduced. On the other hand, when the induction index pr becomes smaller, the determination index X becomes larger and exceeds a predetermined value, whereby the power device B is switched from the parallel state to the connected state. As a result, the supplied power increases and the connection point power P(t) increases.

Also, the timing at which the parallel-off state and the connected state are switched differs depending on the parameter _a2 . For example, if power unit B is the load, the higher the priority, the smaller the parameter _a2 . In FIG. 2, the solid line indicates the judgment index X when the parameter _a2 is set to "0", and the dashed line indicates the judgment index X when the parameter _a2 is set to "-0.5". . The judgment index X indicated by the dashed line becomes less than or equal to a predetermined value (for example, "0") when the guidance index pr is smaller than the judgment index X indicated by the solid line, so that it is easier to connect. That is, the higher the priority (the smaller the parameter _a2 ), the earlier the switching timing from the parallel-off state to the interconnected state when the guidance index pr increases, and when the guidance index pr decreases, The timing of switching from the state to the disconnected state is delayed. If the power equipment B is a power generation equipment, the higher the priority, the larger the parameter _a2 is set. The judgment index X indicated by the solid line becomes more than a predetermined value (for example, "0") when the guidance index pr is larger than the judgment index X indicated by the broken line, so that the interconnection is easier. That is, the higher the priority (the larger the parameter _a2 ), the earlier the switching timing from the parallel-off state to the interconnected state when the guidance index pr decreases, The timing of switching from the state to the disconnected state is delayed.

Next, the operation and effects of the switching device A and the power system G according to this embodiment will be described.

According to the present embodiment, the judgment index calculator 111 calculates the judgment index X based on the common guidance index pr received from the central control device F and a preset optimization problem. Then, the comparison unit 112 compares the determination index X with a predetermined value to determine whether the power device B should be connected to the power system E or disconnected from the power system E. output to The switch 12 performs switching based on the determination result input from the comparator 112 . That is, based on the guidance index pr received from the centralized control device F, the switching device A autonomously switches between interconnection and disconnection of the connected power device B. FIG. Therefore, the central control device F can cause the power device B, which cannot control the input/output power, to perform on/off control based on the induction index pr. As a result, in the power system G, the target managed by the centralized control device F can be expanded to include the power device B whose input/output power cannot be controlled.

Further, according to the present embodiment, each switching device A has its priority set by the parameter _a2 of the calculation formula (see formula (1) above) set in the judgment index calculator 111 . Therefore, each switching device A can change the timing of switching between the connection and the disconnection of the connected power device B according to the priority. Therefore, simultaneous connection or disconnection of a large number of power devices B is suppressed. Further, according to the present embodiment, each switching device A includes a switch 12 and switches between a state in which the power device B is connected to the power system E and a state in which the power device B is disconnected from the power system E. As a result, it is possible to reliably switch between the energized state and the disconnected state.

In the present embodiment, the comparison unit 112 compares the determination index X input from the determination index calculation unit 111 with a predetermined value to determine whether the power device B is connected to the power system E or not. Although the case of judging whether to disconnect from the network has been described, the present invention is not limited to this. The electric power device B, which has been disconnected due to a change in the induction index pr, is reconnected due to a slight change in the induction index pr, and as a result, chattering occurs in which switching between connection and disconnection is repeatedly performed in a short period of time. Sometimes. Frequent chattering may shorten the life of the switch 12 . In order to suppress the occurrence of chattering, the comparison unit 112 may set a predetermined range based on a predetermined value, for example, a range of -0.1 to 0.1 when the predetermined value is "0" as the dead band region. . Note that the predetermined range is not limited. The comparison unit 112 does not switch between interconnection and parallel-off when the determination index X is in the dead zone region. However, if the dead band region is set too wide, fine control becomes impossible, although chattering can be suppressed. In other words, the setting of the dead band region is a trade-off between suppression of chattering and fine control. The dead band area is set so that frequent occurrence of chattering can be suppressed and fine control can be performed to some extent. In addition, by setting the dead band area, even if the power devices B have the same priority, the power device B whose power is turned on first is preferentially interconnected.

Further, in the present embodiment, regardless of the type of the power device B, a common calculation formula (see formula (1) above) is set in the determination index calculation unit 111, and the determination method of the comparison unit 112 is the power device Although the case where it differs depending on the type of B has been described, it is not limited to this. For example, when the power device B is a power generation facility that supplies electric power, the determination index calculation unit 111 is set with the calculation expression shown by the following expression (2), which is obtained by inverting the sign of the expression (1) above, and the comparison unit 112 may be determined in common.

Further, in the present embodiment, a case has been described where the power device B includes a load that consumes power and a power generation facility that supplies power, but the present invention is not limited to this. All power devices B may be loads, or all power devices B may be generators.

FIG. 3 is a diagram for explaining the switching device A' according to the second embodiment, and is a block diagram showing the internal configuration of the switching device A'. In FIG. 3, elements that are the same as or similar to those of the switching device A according to the first embodiment are denoted by the same reference numerals, and overlapping descriptions are omitted. The switching device A′ according to the present embodiment differs from the switching device A according to the first embodiment in the internal configuration of the determination unit 11 .

If a power system G includes many power units B, multiple power units B may have the same priority. In this case, the timing of switching between interconnection and disconnection of these power devices B becomes the same. For example, when these power devices B are the load, the power consumption increases sharply and the induction index pr decreases due to the simultaneous interconnection, whereby the power devices B are disconnected all at once. Then, as the plurality of power devices B are disconnected all at once, the power consumption drops sharply and the induction index pr rises, whereby the plurality of power devices B are interconnected all at once. In this way, simultaneous connection and simultaneous disconnection of a plurality of power devices B may be repeated.

FIG. 4(a) is a time chart showing the time change of each value when simulating a state in which a plurality of power equipments B with the same priority repeat simultaneous interconnection and simultaneous disconnection. In the simulation, 10 power devices B, which are loads with a power consumption of 3 kW, are connected to the power system E via switching devices A, and a fixed load with a power consumption of 90 kW is directly connected to the power system E. It is assumed that there is The ten power units B have the same priority. The upper part shows the time change of the induction index pr. The middle part shows changes over time in power consumption (see a) and target power consumption (see b) of the entire system. The lower part shows the change over time in the number of interconnected power equipments B (loads). In the simulation, the target power consumption up to 4:00 is 80 kW, and the target power consumption from 4:00 is 110 kW. Also, the guidance index pr is calculated every minute.

As shown in FIG. 4(a), until time 4:00, the target power consumption is 80 kW, while the power equipment B is all disconnected, and the total power consumption is 90 kW for the fixed load. is fixed to That is, the total power consumption is greater than the target power consumption, and the induction index pr is fixed at a negative value. As a result, the determination index X is also fixed, and the parallel-off state of the power device B is maintained.

At time 4:00, the target power consumption changed from 80 kW to 110 kW, so that the overall power consumption fell below the target power consumption and the induction index pr increased. As a result, when the judgment index X decreases and becomes equal to or less than a predetermined value, the ten power devices B are interconnected all at once. The total power consumption is 120 kW (=90 kW + 3 kW x 10) due to the interconnection of the 10 power devices B. Since the overall power consumption exceeds the target power consumption, the induction index pr is decreasing. As a result, when the determination index X increases and reaches or exceeds a predetermined value, the ten power units B are disconnected all at once. Thereafter, simultaneous connection and simultaneous disconnection of the ten power devices B are repeated. In FIG. 4A, simultaneous interconnection and simultaneous disconnection are repeated approximately every 10 minutes. The interval between the simultaneous connection and the simultaneous disconnection depends on the total power consumption of the 10 power devices B, the power consumption of the fixed loads, the target value of the total power consumption, the calculation interval of the induction index pr, and the like. Change.

In order to prevent such a state in which simultaneous interconnection and simultaneous disconnection are repeated, the switching device A' selects the selected power device B before the plurality of power devices B are interconnected all at once. interconnect.

The comparison unit 112 of the determination unit 11 according to this embodiment includes a timer unit 113 and a lottery unit 114 . Clocking unit 113 clocks the time for which the parallel-off state of power device B continues. The lottery unit 114 performs a lottery for interconnecting the power device B regardless of the determination index X. For example, the lottery unit 114 generates a random number and determines that the lottery has been won when the generated random number is equal to or greater than a predetermined winning judgment value. The winning determination value is set in advance according to the winning probability. Note that the lottery method performed by the lottery unit 114 is not limited. The lottery unit 114 only needs to be able to randomly set winnings.

The comparison unit 112 according to the present embodiment causes the lottery unit 114 to perform a lottery when the time measured by the clock unit 113 is equal to or longer than a predetermined time. The predetermined time is set to be shorter than the time from simultaneous disconnection of the plurality of power devices B to simultaneous interconnection. As shown in FIG. 4( a ), the plurality of power devices B repeats simultaneous interconnection and simultaneous disconnection every approximately 10 minutes. Therefore, in this embodiment, the predetermined time is set to about 10 minutes. Note that the predetermined time is not limited, and the range of the overall power consumption of the power device B having the same priority, the range of the power consumption of the load, the range of the target value of the overall power consumption, and the calculation interval of the induction index pr. etc., it is set as appropriate. Then, when the lottery unit 114 determines that the lottery is won, the comparison unit 112 determines that the electric power device B is connected to the power system E regardless of the determination based on the comparison of the determination index X. to the switch 12. The switching device A' to which each power device B is connected performs the lottery when the disconnection state continues for a predetermined time, and only the selected switching device A' is connected to the power device. Connect B. Since only some of the power devices B are interconnected before many power devices B are interconnected all at once, a rapid increase in power consumption is suppressed and a decrease in the induction index pr is suppressed. As a result, simultaneous disconnection of power equipment B is suppressed.

FIG. 5 is a flowchart for explaining the lottery process performed by the comparison unit 112. As shown in FIG. The lottery process is started when the comparison unit 112 switches the determination based on the determination index X from interconnection to parallel disconnection.

First, clocking by the timing unit 113 is started (S1). Next, it is determined whether or not the power device B remains disconnected (S2). Specifically, it is determined whether or not the comparison unit 112 has output to the switch 12 the result of determination to disconnect. If the power device B remains disconnected (S2: YES), it is determined whether or not a predetermined time has passed (S3). Specifically, the comparison unit 112 compares the time measured by the time measurement unit 113 with a predetermined time, and determines whether or not the time has exceeded the predetermined time. If the predetermined time has not elapsed (S3: NO), the process returns to step S2 and the determinations of steps S2 and S3 are repeated.

In step S2, if the power device B is interconnected (S2: NO), the lottery is not performed and the lottery process ends. In step S3, when the predetermined time has passed (S3: YES), a lottery is held (S4). Specifically, the lottery unit 114 generates random numbers. Next, it is determined whether or not the prize has been won (S5). Specifically, the lottery unit 114 compares the generated random number with the winning determination value, and determines that the player has won the lottery when the random number is greater than or equal to the winning determination value. If the lottery is won (S5: YES), power device B is interconnected (S6), and the lottery process ends. Specifically, the comparison unit 112 outputs to the switch 12 the determination result that the connection is to be made. On the other hand, if the lottery is not won (S5: NO), the lottery process ends without connecting power device B.

Note that the processing shown in the flowchart of FIG. 5 is an example, and the lottery processing performed by the comparison unit 112 is not limited to the above.

FIG. 4(b) is a time chart showing the time change of each value when a simulation similar to the simulation in FIG. 4(a) is performed using the switching device A'. Each setting in the simulation is the same as in the simulation in FIG. 4(a). Also in FIG. 4(b), the upper part shows the time change of the induction index pr, the middle part shows the time change of the power consumption (see a) and the target power consumption (see b), and the lower part shows the interconnected power devices. It shows the time change of the number of B (load).

As shown in FIG. 4B, until time 4:00, the target power consumption is 80 kW as in the case of FIG. The disconnected state is maintained.

At time 4:00, the target power consumption changed from 80 kW to 110 kW, so that the overall power consumption fell below the target power consumption and the induction index pr increased. As a result, when the judgment index X decreases and becomes equal to or less than a predetermined value, the ten power devices B are interconnected all at once. Since the total power consumption exceeds the target power consumption by connecting the ten power devices B, the induction index pr is decreasing. As a result, when the determination index X increases and reaches or exceeds a predetermined value, the ten power units B are disconnected all at once. However, after about 4:30, a lottery is held before the judgment index X decreases to a predetermined value or less, and several power units B are connected first. As a result, some of the power devices B can be interconnected before ten power devices B are interconnected all at once. In addition, compared to the case where ten power devices B are interconnected all at once, the increase in power consumption as a whole is suppressed, so the decrease in the induction index pr is moderate.

Thus, in the simulation in FIG. 4B, simultaneous interconnection and simultaneous disconnection are less likely to occur. In addition, by suppressing simultaneous interconnection and simultaneous disconnection, fluctuations in the overall power consumption are suppressed and controlled so as not to deviate significantly from the target power consumption.

Also in the present embodiment, the switching device A' autonomously switches between interconnection and disconnection of the connected power device B based on the guidance index pr received from the centralized control device F. FIG. The centralized control device F can cause the power device B, which cannot control the input/output power, to perform on/off control based on the induction index pr. can be extended to power device B, which cannot control . In addition, since the priority of each switching device A' is set by the parameter _a2 , it is possible to vary the timing of switching between connection and parallel disconnection of the connected power device B according to the priority. can. Therefore, simultaneous connection or disconnection of a large number of power devices B is suppressed.

Furthermore, according to the present embodiment, even if there are a plurality of switching devices A' with the same priority, the comparing unit 112 performs the lottery process and connects the switching devices A' with the same priority. Simultaneous disconnection or interconnection is suppressed.

FIG. 6 is a diagram for explaining the switching device A″ according to the third embodiment, and is a block diagram showing the internal configuration of the switching device A″. In FIG. 6, the same or similar elements as those of the switching device A according to the first embodiment are denoted by the same reference numerals, and overlapping descriptions are omitted. The switching device A″ according to the present embodiment differs from the switching device A according to the first embodiment in that the switch 12 is not provided.

The switching device A″ does not switch the power device B between the connected state and the parallel-off state by the switch 12, but turns the power switch of the power device B on and off, thereby switching the power device B between the operating state and the stopped state. Each switching device A″ is associated with a different power device B, respectively. The comparison unit 112 of the switching device A″ outputs to the corresponding power device B the determination result as to whether the corresponding power device B should be in the operating state or in the stopped state. The switching device A″ switches the corresponding power device B to the operating state, whereby the power device B is in an energized state in which power is being received (or transmitted). switch to On the other hand, by switching the corresponding power device B to the stopped state, the power device B switches to the disconnected state in which it does not receive (or transmit) power.

Also in this embodiment, the switching device A″ autonomously switches between the operating state and the stopped state of the corresponding power device B based on the guidance indicator pr received from the centralized control device F. , the power equipment B whose input/output power cannot be controlled can be made to perform on/off control based on the induction index pr. B. In addition, since the priority of each switching device A″ is set by the parameter _a2 , switching between the operating state and the stopped state of the corresponding power device B is determined according to the priority. Timing can be different. Therefore, it is possible to prevent a large number of power devices B from operating or stopping at the same time.

Furthermore, according to the present embodiment, since the switch 12 is not provided, the manufacturing cost of the switching device A″ can be lower than that of the switching device A. Further, the comparison unit 112 is added to the power device B originally connected. Therefore, unlike the switching device A, it need not be inserted in the middle of the power line to which the power device B is connected, and the installation is easy.

In the above first to third embodiments, the electric power system G includes the power conditioners C1 to Cn to which the solar cells are connected and the power conditioners D1 to Dm to which the storage batteries are connected. Illustrated, but not limited to. The electric power system G may not include the power conditioners C1 to Cn, and may not include the power conditioners D1 to Dm. The power system G may also include a power management system such as a BEMS (Building Energy Management System) that manages the power consumption of consumers as a management target.

The switching device and power system according to the present invention are not limited to the above-described embodiments. The specific configuration of each part of the switching device and the electric power system according to the present invention can be varied in design in various ways.

A: switching device, 111: judgment index calculation unit, 112: comparison unit, 113: timer unit, 114: lottery unit, 12: switch, B: power device, E: power system, F: centralized control device, G: power system

Claims (6)

Switching between an energized state in which a power device that is connected to a power system and cannot control input/output power is receiving or transmitting power from the power system, and a non-powered state in which it is neither receiving nor transmitting power a device,
To determine whether the power device should be in the energized state or in the non-energized state based on a guidance index input from a centralized control device that manages the switching device and a preset optimization problem. a judgment index calculator that calculates the judgment index of
a comparison unit that switches between the energized state and the disconnected state based on a comparison result of comparing the judgment index with a predetermined value;
A switching device comprising: further comprising a switch arranged on a connection line that connects the power device and the power system, and switching between a state in which the power device is linked to the power system and a state in which the power device is disconnected from the power system;
The comparison unit instructs switching of the switch based on the comparison result.
The switching device according to claim 1. The determination index calculation unit sets the guidance index to pr and the maximum value of the guidance index to pr ^lmt ,
When a ₂ is a parameter based on priority and a ₁ and a ₃ are arbitrary parameters, the judgment index is calculated as X in the following formula.
The switching device according to claim 1 or 2.

The comparison unit does not switch between the energized state and the disconnected state when the determination index is within a predetermined range based on the predetermined value.
The switching device according to any one of claims 1 to 3. The comparison unit
a timing means for timing the duration of the interruption;
Lottery means for performing a lottery when the time counted by the clock means exceeds a predetermined time;
with
Switching to the energized state regardless of the comparison result when winning by the lottery means;
The switching device according to any one of claims 1 to 4. a plurality of switching devices according to any one of claims 1 to 5;
the central control device that outputs the common guidance index to each of the switching devices;
A power system comprising:

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