Electricity networks and how to change them

Abstract

This power network comprises: a plurality of power routers that each have a plurality of power ports capable of receiving and outputting DC power and are for converting power received from one of the plurality of power ports and outputting the power from at least one other power port; a plurality of link lines connecting the plurality of power routers in a grid via the power ports; and a power device that consumes or supplies power and is connected to at least one of the power ports of the plurality of power routers that is not connected to a link line. At least one of the plurality of output ports of each of the plurality of power routers is made to be a non-modifying port that does not control the characteristics of input or output DC power.

Description

[Technical field]

[0001] The present invention relates to an electric power network and a method for modifying an electric power network. [Background technology]

[0002] In recent years, the introduction of power sources using renewable energy has accelerated in response to the problem of global warming. For example, at the 24th Conference of the Parties to the United Nations Framework Convention on Climate Change (COP24), a target for the global average temperature was set, and the introduction of renewable energy has become a global trend. However, due to frequency stabilization constraints, there are concerns that increasing the introduction rate of renewable energy, which fluctuates greatly and does not have synchronization power (GF (Governor Free), LFC (Load Frequency Control), etc.), could cause disruptions such as large-scale blackouts if the current power system remains unchanged.

[0003] In recent years, technologies related to the introduction of renewable energy have been proposed (Patent Documents 1, 2, Non-Patent Document 1). For example, Patent Document 1 and Non-Patent Document 1 propose a system based on multiple microgrids for local production and consumption, in which the microgrids are connected asynchronously to accommodate surpluses and shortages, and a power router (a so-called digital grid router) as a device for the system. This is said to enable the large-scale introduction of renewable energy. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2011-061970 A [Patent Document 2] International Publication No. 2014 / 033892 [Non-patent literature]

[0005] [Non-Patent Document 1] Rikiya Abe, et al., “Digital Grid: Communicative Electrical Grids of the Future”, IEEE Transactions on Smart Grid (Volume: 2, Issue: 2, June 2011) Summary of the Invention [Problem to be solved by the invention]

[0006] In a power network, microgrids including power sources using renewable energy may be configured by connecting direct current (DC) power paths in a tree shape. However, in such a tree-shaped configuration, it may be difficult to flexibly exchange power between microgrids. In addition, when construction work is carried out in a power network for expansion or to deal with a disconnection, the construction area may be electrically isolated by a switch or the like, but this isolation may interrupt the operation of the power network.

[0007] The present invention has been made in consideration of the above, and aims to provide a power network suitable for flexible power interchange, and a method for changing a power network suitable for flexible power interchange and capable of suppressing interruptions to operations. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems and achieve the object, a power network according to one embodiment of the present invention comprises a plurality of power routers having a plurality of power ports capable of inputting and outputting DC power, and converting power input from any of the plurality of power ports and outputting it from at least one other power port, a plurality of interconnection lines connecting the plurality of power routers in a grid-like manner via the power ports, and a power device that consumes or supplies power and is connected to a power port of at least one of the plurality of power routers that is not connected to the interconnection lines, and at least one of the plurality of power ports of each of the plurality of power routers is set as a normal port in which the characteristics of the input or output DC power are not controlled.

[0009] At least one of the output ports may be connected to a power storage device capable of storing and discharging DC power.

[0010] The normal port of at least one of the plurality of power routers may be connected to a constant voltage control port among the plurality of power ports of at least one other of the power routers, which is set as a port at which the voltage of the input or output DC power is controlled to be constant within a predetermined range.

[0011] At least one of the market ports of the power router having the constant voltage control port connected to the market port may be connected to a power storage device capable of storing and discharging DC power.

[0012] At least one of the power ports of the multiple power routers is a constant power control port set as a port where the voltage of the input or output DC power is controlled to be constant within a predetermined range, and the constant power control port may be connected to a constant current control port among the multiple power ports of another of the power routers, which is set as a power port where the current of the input or output DC power is controlled to be constant within a predetermined range.

[0013] The power router may further include a controller for controlling operation of at least one of the plurality of power routers.

[0014] The control unit may switch at least one power port of the at least one power router between the normal port and a control port set as a port where characteristics of input or output DC power are controlled.

[0015] Each of the multiple power ports of the at least one power router may be connected to each of multiple power storage devices capable of storing and releasing DC power, and the control unit may switch the power port connected to each of the multiple power storage devices between a normal port and a control port depending on the charging state of each of the multiple power storage devices.

[0016] The control unit may switch the power port connected to a power storage device, among the plurality of power storage devices, whose indicator indicating a charging state is close to an upper limit value or a lower limit value, from a market port to a control port.

[0017] The control unit may control operations of at least two of the plurality of power routers.

[0018] The control unit may stop operation of a power router related to a power port that is to be connected via a connection line among the respective power ports of the at least two power routers, and maintain operation of a power router related to a power port other than the power port that is to be connected.

[0019] When the power port to be connected is a market port, the control unit may stop operation of a power router related to the market port and set at least one of the power ports other than the power port to be connected to the market port.

[0020] When the control unit determines that a failure has occurred in at least one of the multiple connection lines and that the power port connected to the connection line where the failure has occurred is a market port, it may switch at least one of the other power ports of the power router having the market port to a market port.

[0021] The control unit may switch a power port of another power router connected to an interconnection line connected to the power port that has been switched to a normal port to a constant voltage control port if the power port is not a constant voltage control port.

[0022] A method for changing a power network according to one embodiment of the present invention includes a power network including a plurality of power routers having a plurality of power ports capable of inputting and outputting DC power, the plurality of power routers converting power input from at least one of the plurality of power ports and outputting the power from at least one other power port, a plurality of interconnection lines connecting the plurality of power routers in a grid-like manner via the power ports, and a power device consuming or supplying power connected to a power port of at least one of the plurality of power routers that is not connected to the interconnection lines, wherein at least one of the plurality of power ports of each of the plurality of power routers is set as a normal port in which characteristics of the input or output DC power are not controlled, and an operation of a power router related to a power port to be connected via an interconnection line among the power ports of at least two of the plurality of power routers is stopped while maintaining operation of a power router related to a power port other than the power port to be connected, and an additional power router is connected to the power port to be connected via the interconnection line.

[0023] When the power port to be connected is a market port, the operation of a power router related to the market port may be stopped and at least one of the power ports other than the power port to be connected may be set to the market port.

[0024] In one embodiment of the present invention, a method for changing a power network includes a power network having a plurality of power ports capable of inputting and outputting DC power, a plurality of power routers each of which converts power input from at least one of the plurality of power ports and outputs the power from at least one other power port, a plurality of connection lines connecting the plurality of power routers in a grid-like manner via the power ports, and a power device that consumes or supplies power and is connected to a power port of at least one of the plurality of power routers that is not connected to the connection lines, wherein at least one of the plurality of power ports of each of the plurality of power routers is set as a market port in which characteristics of the input or output DC power are not controlled, and when a failure occurs in at least one of the plurality of connection lines and it is determined that the power port connected to the connection line where the failure occurs is a market port, at least one of the other power ports of the power router having the market port is switched to the market port.

[0025] If the power port of another power router connected to the tie line connected to the power port switched to the normal port is not a constant voltage control port, the power port may be switched to a constant voltage control port.

[0026] In one aspect of the present invention, a method for changing a power network includes a power network having a plurality of power ports capable of inputting and outputting DC power, a plurality of power routers each of which converts power input from at least one of the plurality of power ports and outputs the power from at least one other power port, a plurality of interconnection lines connecting the plurality of power routers in a grid-like manner via the power ports, and a power device that consumes or supplies power and is connected to a power port of at least one of the plurality of power routers that is not connected to the interconnection lines, wherein at least one of the plurality of power ports of each of the plurality of power routers is set as a market port in which characteristics of the input or output DC power are not controlled, and each of the plurality of power ports of the at least one power router is connected to each of a plurality of power storage devices capable of storing and releasing DC power, and the power port connected to each of the plurality of power storage devices is switched between a market port and a control port depending on a charging state of each of the plurality of power storage devices.

[0027] The power port connected to a power storage device, among the plurality of power storage devices, whose indicator indicating a charging state is close to an upper limit value or a lower limit value may be switched from a market port to a control port. Effect of the Invention

[0028] According to the present invention, at least one of the multiple power ports of each of the multiple power routers is set as a market port in which the characteristics of the input or output DC power are not controlled. As a result, the difference between the inflow and outflow of power in the power router can be adjusted by the market port, so that a power network suitable for flexible power interchange can be provided. Also, according to the present invention, at least one of the multiple power ports of each of the multiple power routers is set as a market port in which the characteristics of the input or output DC power are not controlled, and the operation of the power router related to the power port to be connected by the connection line among the respective power ports of at least two of the multiple power routers is stopped, and the operation of the power router related to the power port other than the connection is maintained, and an additional power router is connected to the power port to be connected by the connection line. As a result, the difference between the inflow and outflow of power in the power router can be adjusted by the market port, and the operation of the power router related to the power port other than the connection can be maintained, so that a method for changing a power network suitable for flexible power interchange and capable of suppressing interruption of operation can be provided. [Brief description of the drawings]

[0029] [Figure 1A] FIG. 1A is a diagram illustrating components of a power network according to an embodiment. [Figure 1B] FIG. 1B is a diagram illustrating another aspect of components of a power network according to an embodiment. [Diagram 2] FIG. 2 is a configuration diagram of the power network according to the first embodiment. [Diagram 3] FIG. 3 is a configuration diagram of a power network according to the second embodiment. [Figure 4] FIG. 4 is a configuration diagram of a power network according to the third embodiment. [Diagram 5] FIG. 5 is an explanatory diagram of a method for expanding a power network according to the fourth embodiment. [Figure 6] FIG. 6 is a diagram illustrating a method for expanding a power network according to the fifth embodiment. [Figure 7] FIG. 7 is a diagram illustrating a method for expanding a power network according to the sixth embodiment. [Figure 8] FIG. 8 is a diagram illustrating a method of operating the power network during a fault according to the seventh embodiment. [Figure 9] FIG. 9 is a diagram illustrating a method of operating a power network during a fault according to the eighth embodiment. [Figure 10] FIG. 10 is an explanatory diagram of a method for switching the power port settings according to the ninth embodiment. [Figure 11] FIG. 11 is a diagram illustrating an example of the droop control. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] Hereinafter, an embodiment will be described with reference to the drawings. Note that the present invention is not limited to the embodiment. In addition, in the description of the drawings, the same or corresponding elements are appropriately designated by the same reference numerals.

[0031] <Components of the power network> First, components of a power network according to an embodiment will be described with reference to Fig. 1A. The power network includes, for example, a microgrid 10 and a power router 21. The microgrid includes a power router 11, a tree-shaped DC bus 12, DC / DC converters 13a, 14a, 15a, 16a, and 17a, a DC / AC converter 18a, an EDLC (Electric Double-Layer Capacitor) 13b, batteries 14b, 15b, and 16b, a PV (PhotoVoltaic) device 17b, and a load 18b as power devices, and an energy management system (EMS) 19.

[0032] <Power router configuration> The power router 11 of the present embodiment includes a plurality of power ports, ie, three power ports 11a1, 11a2, and 11a3, three power measuring units 11b1, 11b2, and 11b3, and a control unit 11c that controls the operation of the power router 11.

[0033] The power ports 11a1, 11a2, and 11a3 are power ports capable of inputting and outputting DC power, respectively. The power router 11 is an example of a power router that converts power input from any of the power ports 11a1, 11a2, and 11a3 and outputs the power from at least one other power port. The power router 11 can be configured, for example, using a power converter of a self-excited type or the like that performs bidirectional power conversion.

[0034] Power measuring units 11b1, 11b2, and 11b3 are measuring devices that measure characteristic values ​​related to the power flowing through corresponding power ports 11a1, 11a2, and 11a3, respectively. The characteristic values ​​measured by power measuring units 11b1, 11b2, and 11b3 include, for example, voltage, current, power flow, and phase.

[0035] The control unit 11c controls the power converter and can control the amount of power flowing through the power ports 11a1 and 11a2. The control unit 11c includes, for example, a calculation unit, a storage unit, and a communication unit.

[0036] The calculation unit performs various calculation processes to realize the functions of the control unit 11c, and is composed of, for example, a CPU (Central Processing Unit), an ASIC (Application Specific Integrated Circuit), an FPGA (field-programmable gate array), a DSP (Digital Signal Processor), a GPU (Graphics Processing Unit), or an appropriate combination of these.

[0037] The storage unit includes, for example, a ROM (Read Only Memory) in which various programs and data used by the calculation unit to perform calculation processing are stored. The storage unit also includes, for example, a RAM (Random Access Memory) used to store a working space when the calculation unit performs calculation processing and results of the calculation processing of the calculation unit. The storage unit may include an auxiliary storage device such as an HDD (Hard Disk Drive) or an SSD (Solid State Drive). At least a part of the functions of the control unit 11c is realized as a functional unit by the calculation unit reading and executing various programs from the storage unit.

[0038] The communication unit is configured to be able to communicate with the power measuring units 11b1, 11b2, and 11b3, and receives information on characteristic values ​​measured by the power measuring units 11b1, 11b2, and 11b3. The received information is stored in the storage unit described above. The communication unit is also configured to be able to communicate with the EMS 19, and can receive control commands from the EMS 19 and transmit to the EMS 19 information on the operating state of the power router 11 and information on the characteristic values ​​stored in the storage unit.

[0039] In the power router 11, the power port 11a1 is connected to the DC bus 12. The power port 11a2 is connected to the power port 21a of the power router 21 via a connection line 101 as a power path. The connection line may be called an Edge. The power router 21 has the same configuration and function as the power router 11. The power port 11a3 is connected to a power port of a power router (not shown) via the connection line 101. The power router 21 includes power ports 21b and 21c in addition to the power port 21a. The power ports 21b and 21c are each connected to a power port of another power router via the connection line 101. That is, the multiple connection lines 101 connect the multiple power routers 11, 21 and other power routers in a grid shape via the power ports. The power port 11a1 is a power port that is not connected to a connection line.

[0040] In the power router 11, the power port 11a1 is set as a through port where the characteristics of the input or output DC power are not controlled. The power port 11a2 is set as a constant voltage control port where the voltage of the input or output power is controlled to be constant. The power port 11a3 is set as a constant current control port where the current of the input or output power is controlled to be constant. The constant voltage control port and the constant current control port are examples of control ports where the characteristics of the input or output DC power are controlled. Note that the voltage or current may vary as long as it is within the allowable range. If the variation is within the allowable range, the voltage or current can be regarded as constant. The allowable range is set in consideration of, for example, the safety and operation stability of devices included in the power network such as the power router.

[0041] Hereinafter, the through port may be described as a d (dependent) port, the constant voltage control port may be described as a CV (Constant Voltage) port, and the constant current control port may be described as a CC (Constant Current) port. In the figure, the settings of the power ports may also be indicated by the symbols "d", "CV", and "CC".

[0042] On the other hand, in the power router 21, the power port 21a is set as a CC port. The power ports of the power router are set to any one of a d port, a CV port, and a CC port.

[0043] Both the power routers 11 and 21 have three power ports, but may also be provided with four or more power ports.

[0044] <Elements connected to the DC bus 12> Next, the elements connected to the DC bus 12 will be described. These elements are connected to the power port 11a1 that is not connected to the cooperation line.

[0045] The EDLC 13b is an electric double layer capacitor, and is an example of a power device that supplies power, and is also an example of a power storage device that can store and release DC power. The DC / DC converter 13a has an input / output port 13a1 electrically connected to the DC bus 12, and an input / output port 13a2 electrically connected to the EDLC 13b. When the DC / DC converter 13a receives the DC power according to the power storage amount (charge amount) from the EDLC 13b at the input / output port 13a2, the DC / DC converter 13a converts the DC power to a constant voltage within a predetermined range and outputs it from the input / output port 13a1 to the DC bus 12. On the other hand, when the DC power of a constant voltage within a predetermined range is input from the DC bus 12 to the input / output port 13a1, the DC / DC converter 13a converts the DC power to a constant voltage within a predetermined range and outputs it from the input / output port 13a2 to the EDLC 13b. That is, the input / output port 13a1 is set as a CV port, and the input / output port 13a2 is set as a d port.

[0046] The battery 14b is a lead-acid battery, and is an example of a power device that supplies power, and is also an example of a power storage device that can store and release DC power. The DC / DC converter 14a has an input / output port 14a1 electrically connected to the DC bus 12, and an input / output port 14a2 electrically connected to the battery 14b. When the DC / DC converter 14a receives from the battery 14b a DC power that is in accordance with the amount of power stored (amount of charge) at its input / output port 14a2, the DC / DC converter 14a converts the DC power to a DC power with a constant voltage within a predetermined range and outputs the DC power from the input / output port 14a1 to the DC bus 12. On the other hand, when the DC / DC converter 14a receives from the DC bus 12 a DC power with a constant voltage within a predetermined range at its input / output port 14a1, the DC / DC converter 14a converts the DC power to a DC power that is in accordance with the voltage at the predetermined range and outputs the DC power from the input / output port 14a2 to the battery 14b. That is, the input / output port 14a1 is set as a CV port, and the input / output port 14a2 is set as a d port.

[0047] The battery 15b is a lithium ion battery, and is an example of a power device that supplies power, and is also an example of a power storage device that can store and release DC power. The DC / DC converter 15a includes an input / output port 15a1 electrically connected to the DC bus 12, and an input / output port 15a2 electrically connected to the battery 15b. The DC / DC converter 15a is a DC / DC converter in which the input / output port 15a1 is set as a CV port, and the input / output port 15a2 is set as a d port.

[0048] The battery 16b is a lithium ion battery, and is an example of a power device that supplies power, and is also an example of a power storage device that can store and release DC power. The DC / DC converter 16a includes an input / output port 16a1 electrically connected to the DC bus 12, and an input / output port 16a2 electrically connected to the battery 16b. The DC / DC converter 16a is a DC / DC converter in which the input / output port 16a1 is set as a CV port, and the input / output port 16a2 is set as a d port.

[0049] The batteries 14b, 15b, and 16b may be batteries mounted on an electric vehicle or a hybrid vehicle.

[0050] The EDLC 13b and the batteries 14b, 15b, and 16b may also include a known BMS (Battery Management System) that acquires information about the charging state, such as voltage and temperature. The BMS includes, for example, a sensor, a microcomputer, and an input / output interface. The BMS transmits the acquired information about the charging state to a DC / DC converter connected thereto or an EMS, which will be described later. The BMS may be provided outside the EDLC 13b and the batteries 14b, 15b, and 16b, or may be included in the DC / DC converter connected thereto.

[0051] The PV device 17b is an example of a power device that supplies (generates) power by photovoltaic power generation. The power generation capacity of the PV device 17b changes depending on weather conditions, so the optimal operating point at which the output power is maximized also changes. The DC / DC converter 17a has an input / output port 17a1 electrically connected to the DC bus 12 and an input / output port 17a2 electrically connected to the PV device 17b. When the DC / DC converter 17a receives the current DC power corresponding to the amount of power generated from the PV device 17b at the input / output port 17a2, the DC / DC converter 17a performs control of the MPPT (Maximum Power Point Tracking) method, in which the operating point tracks so that the output power is maximized at the amount of power generated. The DC / DC converter 17a outputs the current DC power corresponding to the maximum output power from the input / output port 17a1 to the DC bus 12. That is, the input / output port 17a1 is set as a d port.

[0052] The load 18b is an example of a power device that consumes AC power. The DC / AC converter 18a includes an input / output port 18a1 electrically connected to the DC bus 12 and an input / output port 18a2 electrically connected to the load 18b. When DC power with a constant voltage within a predetermined range is input from the DC bus 12 to the input / output port 18a1, the DC / AC converter 18a converts the DC power to AC power with a constant power within a predetermined range and outputs the AC power from the input / output port 18a2 to the load 18b. The load 18b operates using this AC power. That is, the input / output port 18a2 is set as a d port, and the input / output port 18a2 is set as a constant power control port.

[0053] The EMS 19 is a system for managing the state of the microgrid 10 in an integrated manner. The EMS 19 controls the DC / DC converters 13a, 14a, 15a, 16a, and 17a and the DC / AC converter 18a to control the electric power that is the object of control of the current, voltage, or power among the electric power inputted and outputted to and from these converters. The DC / DC converters 13a, 14a, 15a, 16a, and 17a, which are electric power converters, and the DC / AC converter 18a are provided with an electric power measuring unit similar to the electric power measuring unit 11b1 that measures characteristic values ​​related to electric power for control, and are configured to be able to communicate information on the measurement results of the characteristic values ​​to the EMS 19. The EMS 19 controls the operation of each electric power converter based on the received information on the measurement results. The EMS 19 also receives information on the operating state of the power router 11 and information on the characteristic values ​​stored in the storage unit from the control unit 11c of the power router 11, and transmits a control command to the control unit 11c based on this information. That is, the EMS 19 can control the operation of the power router 11. The EMS 19 may be configured to be capable of communicating with the EMS of another microgrid. In this case, the EMS 19 may also control the operation of at least two power routers, the power router 11 and the power router of the other microgrid.

[0054] The EMS 19 includes, for example, a calculation unit, a storage unit, and a communication unit, similar to the control unit 11c. The calculation unit includes a CPU, an ASIC, an FPGA, a DSP, a GPU, or an appropriate combination of these, which performs various calculation processes to realize the functions of the EMS 19. The storage unit includes a ROM in which various programs and data used by the calculation unit to perform the calculation processes are stored, a RAM for storing a working space when the calculation unit performs the calculation processes and results of the calculation processes of the calculation unit, and may include an auxiliary storage device such as an HDD or SSD. At least a part of the functions of the control unit is realized as a functional unit by the calculation unit reading and executing various programs from the storage unit.

[0055] 1B is a diagram illustrating another aspect of components of a power network according to an embodiment, in which the microgrid 10 shown in FIG. 1 is replaced with a microgrid 10A.

[0056] Microgrid 10A has a configuration in which DC bus 12 is replaced with a DC bus 12A, DC / DC converter 14a is replaced with a DC / DC converter 14Aa, and a DC / AC converter 31 is added in the configuration of microgrid 10.

[0057] The DC / AC converter 31 has an input / output port 31a on the DC side electrically connected to the DC bus 12, and an input / output port 31b on the AC side electrically connected to the power system 32 of the power company. When the DC / AC converter 31 receives the current AC power from the power system 32 at the input / output port 31b, the DC / AC converter 31 converts the current AC power to a constant voltage within a predetermined range and outputs the current DC power from the input / output port 31a to the DC bus 12A. When the DC power from the DC bus 12A receives the current DC power to the input / output port 31a, the DC / AC converter 31 converts the current AC power to a constant voltage within a predetermined range and outputs the current AC power from the input / output port 31b to the power system 32. That is, the input / output port 31a is set as a CV terminal port, and the input / output port 31b is set as a d port. This allows the microgrid 10A to receive power from the power system 32 and to output (for example, sell) power to the power system 32.

[0058] In the microgrid 10A, the DC / DC converter 14Aa includes an input / output port 14Aa1 electrically connected to the DC bus 12A and an input / output port 14Aa2 electrically connected to the battery 14b. When DC power with a constant current within a predetermined range is input to the input / output port 14Aa2 from the battery 14b, the DC / DC converter 14Aa converts the DC power into running DC power and outputs it from the input / output port 14a1 to the DC bus 12A. On the other hand, when running DC power from the DC bus 12A is input to the input / output port 14Aa1, the DC / DC converter 14Aa converts the DC power into a constant current within a predetermined range and outputs it from the input / output port 14Aa2 to the battery 14b. That is, the input / output port 14Aa1 is set as a d port, and the input / output port 14Aa2 is set as a CC port.

[0059] Each embodiment will be described based on the above description of the components.

[0060] (Embodiment 1) Fig. 2 is a configuration diagram of a power network according to the first embodiment. The power network 100 includes a plurality of nodes each having a plurality of power ports, and a plurality of connection lines that connect these nodes in a grid shape via the power ports. Fig. 2 shows nodes N1 and N2 among the plurality of nodes, and power paths P1, P2, P3, P4, P5, and P6 among the plurality of connection lines.

[0061] The nodes N1 and N2 are configured as microgrids including a power router, a DC bus, and various power devices, such as the microgrids 10 and 10A shown in Figures 1A and 1B, respectively. However, the multiple nodes of the power network 100 may include a node that is configured only with a power router. In other words, each node is equipped with a power router.

[0062] The power ports T11, T12, and T13 of the power router of node N1 are set as a CV port, a d port, and a CC port, respectively. The power ports T21, T22, T23, and T24 of the power router of node N2 are set as a d port, a CV port, a CC port, and a CC port, respectively. The types of the power ports of the nodes may be mutually switchable under the control of a control unit of the power router.

[0063] The power path P1 connects the power port T11, which is a CV port of the node N1, to the power port T21 of the node N2. The power path P2 connects the power port T12 of the node N1 to a power port of another node. The power path P3 connects the power port T13 of the node N1 to a power port of another node. The power path P4 connects the power port T22 of the node N2 to a power port of another node. The power path P5 connects the power port T23 of the node N2 to a power port of another node. The power path P6 connects the power port T24 of the node N2 to a power port of another node.

[0064] At least one of the power ports of each node is set as a d port. One end of each tie line is connected to a CV port. The other end of each tie line is connected to a d port or a CC port.

[0065] In this way, in the power network 100, since at least one of the multiple power ports of each node is set as a d port, the difference between the inflow and outflow of power at each node can be adjusted by the d port. In this case, the d port functions as a buffer. For example, in node N1, when power flows out from power ports T11 and T13, the same amount of power as the sum of the outflow amounts flows into the d port. In addition, when a first amount of power flows out from the power port T11 and a second amount of power that is greater than the first amount flows in from the power port T13, the amount of power that is the difference between the second amount and the first amount flows out from the d port. As a result, the power network 100 has a network configuration suitable for flexible power interchange using the d port. In addition, one end of each connection line is connected to a CV port. This stabilizes the voltage of the power input and output to the connection line. In addition, if the other end of the connection line is connected to a CC port, the voltage and the flow of the connection line are controlled at the same time, so that a more suitably controlled connection line is realized.

[0066] (Embodiment 2) 3 is a configuration diagram of a power network according to embodiment 2. The power network 200 includes a plurality of nodes N3, N4, N5, N6, N7, N8, and N9, power paths P7, P8, P9, P10, P11, P12, P13, P14, P15, P16, P17, P18, P19, P20, P21, P22, and P23, and batteries B3, B4, B5, B6, B7, B8, and B9.

[0067] Node N3 has power ports T31, T32, T33, and T34, which are set to d port, CV port, CC port, and CC port, in that order. Node N4 has power ports T41, T42, T43, and T44, which are set to d port, CV port, CV port, and CC port, in that order. Node N5 has power ports T51, T52, T53, and T54, which are set to CV port, CC port, d port, and CC port, in that order.

[0068] Node N6 has power ports T61, T62, T63, T64 and T65, which are set to CV port, CV port, CV port, d port, in that order. Node N7 has power ports T71, T72, T73 and T74, which are set to CC port, CV port, d port, CV port, in that order. Node N8 has power ports T81, T82 and T83, which are set to CC port, d port, CC port, in that order. Node N9 has power ports T91, T92 and T93, which are set to CC port, CC port, d port, CC port, in that order.

[0069] Batteries B3, B4, B5, B6, B7, and B8 are examples of power storage devices capable of storing and discharging DC power.

[0070] The power path P7 is an interconnection line that connects the power port T32, which is the CV port of the node N3, and the power port T44, which is the CC port of the node N4. Therefore, this power path P7 is an interconnection line in which the voltage and the power flow are controlled. Such an interconnection line may be referred to as a control interconnection line. The power path P8 connects the battery B3 and the power port T31, which is the d port of the node N3. The power path P9 connects the power port T33, which is the CC port of the node N3, and the power port T51, which is the CV port of the node N5, and is a control interconnection line in which the voltage and the power flow are controlled. The power path P10 connects the power port T34, which is the CC port of the node N3, and the power port T61, which is the CV port of the node N6, and is a control interconnection line in which the voltage and the power flow are controlled.

[0071] The power path P11 connects the battery B4 and the power port T41, which is the d port of the node N4. The power path P12 connects the power port T42, which is the CV port of the node N4, and the power port T81, which is the CC port of the node N8, and is a control link line in which the voltage and power flow are controlled. The power path P13 connects the power port T43, which is the CV port of the node N4, and the power port T52, which is the CC port of the node N5, and is a control link line in which the voltage and power flow are controlled.

[0072] The power path P14 connects the battery B5 and the power port T53, which is the d port of the node N5. The power path P15 connects the power port T54, which is the CC port of the node N5, and the power port T62, which is the CV port of the node N6, and is a control linkage line in which the voltage and power flow are controlled. The power path P16 connects the power port T63, which is the CV port of the node N6, and the power port T71, which is the CC port of the node N7, and is a control linkage line in which the voltage and power flow are controlled. The power path P17 connects the power port T64, which is the CV port of the node N6, and the power port T91, which is the CC port of the node N9, and is a control linkage line in which the voltage and power flow are controlled.

[0073] The power path P18 connects the battery B6 and the power port T65 which is the d port of the node N6. The power path P19 connects the power port T72 which is the CV port of the node N7 and the power port T83 which is the CC port of the node N8, and is a control link line in which the voltage and power flow are controlled.

[0074] The power path P20 connects the battery B7 to the power port T73, which is the d port of the node N7. The power path P21 connects the power port T74, which is the CV port of the node N7, to the power port T92, which is the CC port of the node N9, and is a control link line in which the voltage and power flow are controlled. The power path P22 connects the battery B8 to the power port T82, which is the d port of the node N8. The power path P23 connects the battery B9 to the power port T93, which is the d port of the node N9.

[0075] In the power network 200, the voltage and power flow of all the power paths P7, P9, P10, P12, P13, P15, P16, P17, P19, and P21, which are the connection lines, are controlled. In addition, since all the nodes N3, N4, N5, N6, N7, N8, and N9 are connected to the d port of batteries B3, B4, B5, B6, B7, B8, and B9, which serve as buffers, respectively, the difference between the amount of power inflow and outflow can be adjusted at each node, and a flexible network configuration is realized in which any power can be exchanged on all the connection lines.

[0076] (Embodiment 3) Fig. 4 is a configuration diagram of a power network according to embodiment 3. A power network 200A has a configuration in which batteries B3, B4, B8, and B9 are deleted from the configuration of the power network 200 shown in Fig. 3, and power paths P7, P10, P12, and P17 are replaced with P7A, P10A, P12A, and P17A, respectively. Also, in nodes N3, N4, N8, and N9, connection destinations of some power ports are changed.

[0077] Specifically, in node N3, power port T31 set to port d is connected to power path P10A. As a result, power path P10A is not an interconnection line in which both voltage and power flow are controlled, since one end is connected to port d and the other end is connected to power port T61, which is a CV port of node N6. Such an interconnection line may be referred to as a non-controlled interconnection line. In the drawings, non-controlled interconnection lines are indicated by dashed lines.

[0078] In addition, in node N4, power port T41 set to port d is connected to power path P7A. As a result, power path P7A is an uncontrolled connection line with one end connected to port d and the other end connected to power port T32, which is a CV port of node N3.

[0079] In addition, in node N8, power port T82 set to port d is connected to power path P12A. As a result, power path P12A is an uncontrolled connection line with one end connected to port d and the other end connected to power port T42, which is a CV port of node N4.

[0080] In addition, in node N9, power port T93 set to port d is connected to power path P17A. As a result, power path P17A is an uncontrolled connection line with one end connected to port d and the other end connected to power port T64, which is a CV port of node N6.

[0081] In the power network 200A, the d ports of the nodes N5, N6, and N7, each having a CV port connected to the d port by a connection line, are connected to the batteries B5, B6, and B7, respectively. In the power network 200A, not all connection lines are control connection lines, but by connecting the d port of a node from which a battery has been removed (for example, the d port of node N9) to the CV port of a node from which a battery has not been removed (for example, the CV port of node N6), a network configuration is realized that can perform flexible power interchange while reducing the number of batteries.

[0082] (Embodiment 4) Next, a method of expanding a power network will be described as an example of a method of changing a power network. FIG. 5 is an explanatory diagram of a method of expanding a power network according to a fourth embodiment. The power network 300 shown in FIG. 5 has a configuration in which the node N2 is replaced with a node N10 in the configuration of the power network 100 shown in FIG. 2. The node N10 has power ports T101, T102, T103, and T104. The power port T101 is a CC port, and is connected to a power port T11, which is a CV port of the node N1, via a power path P1. The power port T102 is a CV port, and is connected to another node via a power path P31. The power port T103 is a CC port, and is connected to another node via a power path P32. The power port T104 is a d port, and is connected to another node via a power path P33.

[0083] To expand this power network 300, a power port T111 of node N11 can be connected to an empty power port T14 of node N1 via a power path P14. At this time, if one of power ports T14 and T111 is set as a CV port and the other as a CC port, the power path P14 can be used as a control link line. Also, the expansion work can be carried out without interrupting the operation of the other power ports T11, T12, and T13 of node N1.

[0084] (Embodiment 5) Fig. 6 is an explanatory diagram of a method for expanding a power network according to embodiment 5. A power network 300A shown in Fig. 6 has a configuration in which an EMS 310 capable of controlling the operation of all nodes is added to the power network 300 shown in Fig. 5. Such an EMS 310 may be called a center EMS.

[0085] Suppose a new node is added between node N1 and node N10 in power network 300A. In this case, first, EMS 310 stops the operation of node N1 and node N10 related to power ports T11 and T101, which are power ports to be connected by a tie line among the power ports of node N1 and node N10, and maintains the operation of node N1 and node N10 related to power ports other than the power ports to be connected.

[0086] Next, the power path P1 is removed, and the power port T121 and power port T11 of the additional node N12 are connected by a power path P41 as a connection line, and the power port T122 and power port T101 are connected by a power path P42 as a connection line. The other power port T123 of node N12 may be connected to another node by a power path P43. Note that with regard to the power ports connected to the power paths P41, P42, and P43, one is set as a CV port and the other as a CC port or d port. After that, EMS310 resumes the stopped operations of nodes N1 and N10, and starts the operation of node N12.

[0087] According to this method, for nodes N1 and N10, only operations related to the power ports to be connected are stopped, while operations related to the other power ports are maintained, so that expansion work can be carried out while minimizing the extent of interruption to the operation of the power network 300A.

[0088] (Embodiment 6) Fig. 7 is an explanatory diagram of a method for expanding a power network according to embodiment 6. A power network 100A shown in Fig. 7 has a configuration in which an EMS 110 capable of controlling the operation of all nodes is added to the power network 100 shown in Fig. 2.

[0089] In the power network 100A, a new node is added between the node N1 and the node N2. In this case, the EMS 110 first stops the operation of the node N1 and the node N2 related to the power ports T11 and T21, which are the power ports to be connected by the connection line among the power ports of the node N1 and the node N2, and maintains the operation of the node N1 and the node N2 related to the power ports other than the power ports to be connected. However, since the power port T21 was set as the d port, if the operation is stopped, the d port of the node N2 will be absent. Therefore, before stopping the operation of the node N2 related to the power port T21, the EMS 110 checks the existence of a power port that is an electronic port other than the power port to be connected to the node N2 and is set as a CC port. Here, since the power ports T23 and T24 are CC ports, for example, the power port T24 is set to be changed to the d port.

[0090] Next, the power path P1 is removed, and the power port T131 and power port T11 of the additional node N13 are connected by a power path P51 as a connection line, and the power port T132 and power port T21 are connected by a power path P52 as a connection line. The other power port T133 of node N13 may be connected to another node by a power path P53. After that, EMS110 resumes the stopped operations of nodes N1 and N2, and starts the operation of node N13.

[0091] According to this method, for nodes N1 and N2, only the operation related to the power ports to be connected is stopped, and the operation related to the other power ports is maintained, so that the expansion work can be carried out while suppressing the degree of interruption to the operation of the power network 100A. In addition, since the d port is secured for node N2, flexible power interchange of the power network 100A is maintained.

[0092] In this method, the power port set as the CC port is changed to the d port. On the other hand, if all electronic ports other than the one to be connected are CV ports, the EMS appropriately selects one of the CV ports, changes the power port of the node connected to that CV port by the connection line to a CV port, and then changes the selected CV port to the d port. This ensures that one side of the connection line is connected to the CV port.

[0093] (Embodiment 7) Next, a method of operating a power network during a failure will be described as an example of a method of changing a power network. Fig. 8 is an explanatory diagram of a method of operating a power network during a failure according to embodiment 7. A power network 200B shown in Fig. 8 has a configuration in which an EMS 210 capable of controlling the operation of all nodes is added to the power network 200A shown in Fig. 4.

[0094] 8, assume that a disconnection occurs in power path P17A, which is a connection line connecting power port T64, which is a CV port of node N6, and power port T93, which is a d port of node N9. When the disconnection occurs, EMS210 detects the disconnection from information on the measurement results transmitted from the control units of the power routers provided in each of nodes N6 and N9. Alternatively, when the disconnection occurs, the control units of the power routers provided in each of nodes N6 and N9 may transmit information to EMS210 that the disconnection has occurred.

[0095] When the EMS210 detects the occurrence of a disconnection, it stops the operation of the node N6 related to the power port T64 connected to the power path P17A and the operation of the node N9 related to the power port T93. Before stopping the operation of the node N9 related to the power port T93, the EMS210 determines that the power port T93 is a d port, sends a control command to the node N9, and executes a port type switching to switch the power port T92 set as a CC port to the d port. This ensures the d port in the node N9. Note that when the power port T92 is switched to the d port, the power path P20 connecting the power port T92 and the power port T74 of the node N7 changes from a control connection line to a non-control connection line.

[0096] According to this method, it is possible to reduce the degree of interruption of operations while maintaining flexible power interchange in the power network 200B.

[0097] (Embodiment 8) 9 is an explanatory diagram of a method for operating a power network during a failure according to embodiment 8. This embodiment will also be described with reference to a power network 200B, as in embodiment 7.

[0098] 9, it is assumed that a disconnection occurs in power path P7A, which is a connection line connecting power port T32, which is a CV port of node N3, and power port T41, which is a d port of node N4. When the disconnection occurs, EMS210 detects the occurrence of the disconnection from information on the measurement result transmitted from the control units of the power routers provided in each of nodes N3 and N4. In addition, when the disconnection occurs, the control units of the power routers provided in each of nodes N3 and N4 may transmit information to EMS210 that the disconnection has occurred.

[0099] When the EMS210 detects the occurrence of a disconnection, it stops the operation of the node N3 related to the power port T32 connected to the power path P7A and the operation of the node N4 related to the power port T41. Before stopping the operation of the node N4 related to the power port T41, the EMS210 determines that the power port T41 is a d port. The EMS210 also confirms that the other power ports in the node N4 besides the power port T41 are CV ports. Thereafter, it transmits a control command to the node N4, and transmits a control command to the control unit of the power router of the node N4 to execute port type switching to switch, for example, the power port T43 among the power ports set as CV ports, to the d port (port type switching (1)). This ensures the d port in the node N4. When the control unit of the power router of the node N4 completes the switching, it notifies the EMS210 of the completion.

[0100] On the other hand, before switching the power port T43 to the d port, the EMS210 checks the type of the other power port connected to the power path P13 connected to the power port T43. In this example, the power port to which the power path P13 is connected is the power port T52 of the node N5, which is set to the CC port. In this case, the EMS210 determines that the power port T52 is not a CV port, and transmits a control command to the control unit of the power router of the node N5 to execute port type switching to switch the power port T52 to a CV port (port type switching (2)). When the control unit of the power router of the node N5 completes the switching, it notifies the EMS210 of the completion. After receiving the completion notification, the EMS210 executes switching of the power port T43 to the d port. As a result, the power path P13 changes to a non-controlled link line, but since one end is connected to a CV port, the voltage is controlled to be constant.

[0101] According to this method, it is possible to suppress interruption of operation while maintaining flexible power interchange in the power network 200B. Also, it is possible to ensure a state in which the voltage of the tie line is controlled to a constant level.

[0102] The fault operation methods according to the seventh and eighth embodiments can be applied not only to disconnections but also to various faults such as short circuits and ground faults.

[0103] (Embodiment 9) Next, as an example of a power network change method, a method of switching the setting of a power port according to the charging state of a power storage device will be described. FIG. 10 is an explanatory diagram of a method of switching the setting of a power port according to the ninth embodiment. The power network 400 shown in FIG. 10 includes a plurality of nodes having a plurality of power ports and a plurality of connection lines connecting these nodes in a grid shape via the power ports, similar to the power network of the first embodiment. In FIG. 10, among the plurality of nodes, the node N21 and the node N22 are shown, and among the plurality of connection lines, the power paths P61, P62, P63, P64, P65, and P66 are shown. Furthermore, the power network 400 includes batteries B21 and B22, and an EMS 410 capable of controlling the operation of all the nodes. The batteries B21 and B22 include a BMS. The batteries B21 and B22 are examples of a plurality of power storage devices. The batteries B21 and B22 are examples of power storage devices, for example, lithium ion batteries.

[0104] The power path P61 connects the power port T211 of the node N21 and the power port T223 of the node N22. The power path P62 connects the power port T212 of the node N21 and the battery B21. The power path P63 connects the power port T213 of the node N21 and a power port of another node. The power path P64 connects the power port T221 of the node N22 and the battery B21. The power path P65 connects the power port T222 of the node N22 and a power port of another node. The power path P66 connects the power port T224 of the node N22 and a power port of another node.

[0105] In this power network 400, an EMS 410 switches the power ports T212, T221 connected to the batteries B21, B22, respectively, between the d port and the control port depending on the charging states of the batteries B21, B22.

[0106] For example, the power port T212 is switched from the CC port setting as shown in the upper diagram of FIG. 10 to the d port setting as shown in the lower diagram. The power port T212 is also switched from the d port setting to the CC port setting. The power port T221 is also switched from the d port setting as shown in the upper diagram of FIG. 10 to the CC port setting as shown in the lower diagram. The power port T221 is also switched from the CC port setting to the d port setting. These switchings are performed by the EMS410 acquiring the charging state from the information on the charging state of the batteries B21, B22 acquired by the BMS, and according to the acquired charging state. The charging state is acquired by calculation by the calculation unit, by referring to table data stored in the storage unit, or the like. The table data to be referred to stores the correspondence between the information on the charging state and the charging state.

[0107] The method of the ninth embodiment will be described below using a specific example. In the diagram shown in the upper part of Fig. 10, the battery B22 is connected to the d port and functions as a buffer. The battery B22 is also connected to the CC port. In this state, the battery B22 has a small regulation margin, and the battery B21 has a large regulation margin.

[0108] Here, the regulation margin means the degree of function as a buffer, and a large regulation margin means a high function as a buffer. For example, in a certain battery, when the SoC (State Of Charge), which is an example of an index of the charging state, is a value close to an upper limit value (e.g., 100%), the function as a discharge buffer for discharging power is high, and the regulation margin is large, whereas when the SoC is a value close to a lower limit value (e.g., 0%), the function as a charge buffer for charging power is low, and the regulation margin is small. In addition, when the SoC is far from the upper limit value and the lower limit value (e.g., about 50%), it can be said that the function as both a discharge buffer and a charge buffer is high. In this embodiment, the EMS 410 determines that a battery whose SoC is far from the upper limit value and the lower limit value, for example, closer to 50%, has a large regulation margin. In addition, the EMS 410 determines that a battery whose SoC is close to the upper limit value or the lower limit value, for example, farther from 50%, has a small regulation margin.

[0109] When the EMS410 determines from the SoC acquired from information from the BMS that the regulating margin of battery B22 is smaller than the regulating margin of battery B21 (SoC is close to the upper or lower limit), it switches the power port T221 connected to battery B22 from the d port to the CC port, and switches the power port T212 connected to battery B21 from the CC port to the d port. Note that in order to perform the switching while maintaining the buffer function of at least one of batteries B21 and B22, the power port T221 may be switched to the CC port after switching the power port T212 to the d port.

[0110] In the upper diagram of FIG. 10, when the power port T221 in the node N22 is the d port, the power ports T222, T223, and T224 are the CV port, the CV port, and the CC port, respectively. In this case, if the power port T221 is switched to the CC port, the d port in the node N22 will disappear. Therefore, in order to maintain the existence of the d port, the power port T221 may be switched to the CC port after the power port T223 is switched from the CV port to the d port. In the upper diagram of FIG. 10, when the power port T212 in the node N21 is the CC port, the power ports T211 and T213 are the d port and the CV port, respectively. In this case, if the power port T223 in the node N22 is switched to the d port, the stability of the voltage in the power path P61, which is the connection line, may decrease. Therefore, in order to ensure the stability of the voltage on the power path P61, the power port T211 may be switched from the d port to the CV port, and then the power port T223 may be switched to the d port.

[0111] Therefore, an example of the order of switching the power ports is as follows: first, power port T212 is switched to the d port; then, power port T211 is switched to the CV port; then, power port T223 is switched to the d port; then, power port T221 is switched to the CC port.

[0112] According to the method of the ninth embodiment, while maintaining flexible power interchange in the power network 400, it is possible to increase the adjustment margin as a buffer of the battery, which is a power storage device.

[0113] In the method according to the ninth embodiment, the EMS 410 determines that the battery B21, B22, whose SoC is far from the upper limit and the lower limit, has a large adjustment margin, and determines that the battery B21, B22, whose SoC is close to the upper limit or the lower limit, has a small adjustment margin. However, the criteria for determining the adjustment margin are not limited to this. For example, the EMS 410 may determine that the battery B21, B22, whose acquired remaining capacity is far from the maximum capacity and the minimum capacity, has a large adjustment margin. In this case, the remaining capacity of the battery is an index of the charging state. For example, when the batteries B21, B22 are batteries with different maximum capacities, it may be better to use the remaining capacity of the battery as an index of the charging state. In addition, when there are multiple batteries, the power port connected to the battery with the smallest adjustment margin may be switched from the d port to the CC port, or the power port connected to two or more batteries whose adjustment margin determined based on the index indicating the charging state is smaller than a predetermined standard may be switched from the d port to the CC port.

[0114] In addition, the judgment conditions for switching the power port connected to the battery from the d port to the CC port are not limited to the above. For example, the EMS 410 may execute control such that, when it is judged that the SoC of the battery connected to the power port that is the d port is within a predetermined range, the EMS 410 maintains the setting of the d port, and when it is judged that the SoC is out of the predetermined range, the EMS 410 switches to the CC port. The predetermined range is, for example, a range with a lower limit of 20% or 30% and an upper limit of 70% or 80%, but may be a range that differs depending on the battery. In addition, the EMS 410 may execute control to switch depending on whether the remaining capacity is within or out of the predetermined range, not limited to the SoC.

[0115] Furthermore, the EMS 410 may acquire power generation and demand forecast information for the power network 400 from another EMS or an external server. The power generation and demand forecast information includes forecast information for power generation in the power network 400 and forecast information for power demand. For example, if the power network 400 includes a PV device, the information may include information on the season, current weather, and future weather forecast for the area in which the PV device is installed. For example, if the power network 400 includes a battery mounted on an electric vehicle such as an electric vehicle or a hybrid vehicle, the information may include information on the supply and demand of power by these electric vehicles.

[0116] The EMS 410 may change the criterion for determining whether the adjustment margin is large or small based on the acquired power generation amount / demand forecast information. For example, when information is obtained that predicts that the power generation amount will increase in the future, it is desirable for the buffer to have a large amount of chargeable power, so it may be determined that a battery with an SoC closer to the lower limit is a battery with a high adjustment margin. Also, for example, when information is obtained that predicts that the demand for power will increase in the future, it is desirable for the buffer to have a large amount of dischargeable power. Therefore, it may be determined that a battery with an SoC closer to the upper limit is a battery with a high adjustment margin. The change of the judgment criterion by the EMS 410 is performed, for example, by a calculation by a calculation unit or by referring to table data stored in a storage unit.

[0117] Furthermore, the EMS 410 may change a predetermined range related to an index (for example, SoC) that is set for switching the power port, based on the obtained power generation amount / demand forecast information.

[0118] In addition, in the method according to the ninth embodiment, the power port connected to the battery is switched between the d port and the CC port, but it may be switched between the d port and the CV port, which is a control port.

[0119] In the method according to the ninth embodiment, the power port settings are switched according to the charging states of the batteries B21 and B22 connected to the power routers of different nodes. However, in a method according to another embodiment, the power port settings may be switched according to the charging states of each of the batteries connected to each of the power ports of the power router of the same node.

[0120] 1A and 1B, an input / output port set as a CV port (for example, input / output port 15a1) may be droop-controlled so that the relationship between the voltage on the DC bus 12 side and the input / output power follows a reference function having a predetermined droop characteristic. Here, the "droop characteristic" means a droop characteristic, and is a characteristic in which the relationship between the voltage and the input / output amount of power has a relationship other than a relationship in which the input / output amount of power is constant over a predetermined voltage range or a relationship in which the voltage is constant over a predetermined range of the input / output amount of power.

[0121] 11 is an explanatory diagram of an example of droop control for the input / output port 15a1. When the voltage on the DC bus 12 side is between V2 and V3, the microgrid 10 is in a normal state where the power supply and demand is average, and the reference function is set so that the battery 15b is in a state where there is no charging or discharging (P=0).

[0122] Furthermore, when the voltage on the DC bus 12 side is between V1 and V2, the microgrid 10 is in a first quasi-normal state in which the power demand is greater than in the normal state and the voltage has dropped, and the reference function is set to execute droop control in which the battery 15b discharges with a relatively large droop coefficient. On the other hand, when the voltage on the DC bus 12 side is between V3 and V4, the microgrid 10 is in a second quasi-normal state in which the power demand is less than in the normal state and the voltage has risen, and the reference function is set to execute droop control in which the battery 15b charges with a relatively large droop coefficient.

[0123] Furthermore, when the voltage on the DC bus 12 side is less than V1, the microgrid 10 is in a transient state where the power demand is even greater than the first quasi-normal state, and the reference function is set to discharge the battery 15b at a specified maximum power P1. On the other hand, when the voltage on the DC bus 12 side is greater than V4, the microgrid 10 is in a transient state where the power demand is even less than the second quasi-normal state, and the reference function is set to charge the battery 15b at a specified maximum power |P2|.

[0124] Furthermore, in the power network of the above embodiment, if any node has the configuration of the microgrid 10 or 10A, the EDLC 13b and the batteries 14b, 15b, and 16b are connected to the d port of the microgrid 10, so that the microgrid 10 as a whole functions as a power storage device. Similarly to the microgrid 10A, the d port of any node may be connected to the power grid of a power company, and the difference between the inflow and outflow of power may be adjusted by receiving or selling power.

[0125] Furthermore, the present invention is not limited to the above-mentioned embodiment. The present invention also includes a configuration in which the above-mentioned components are appropriately combined. Further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspects of the present invention are not limited to the above-mentioned embodiment, and various modifications are possible. [Explanation of symbols]

[0126] 10, 10A Microgrid 11, 21 Power Router 11a1, 11a2, 11a3, 21a, 21b power ports 11b1, 11b2, 11b3 Power measurement section 11c Control section 12 DC Bus 13a, 14a, 14Aa, 15a, 16a, 17a DC / DC Converters 13a1, 13a2, 14a1, 14Aa1, 14a2, 14Aa2, 15a1, 15a2, 16a1, 16a2, 17a1, 17a2, 18a1, 18a2 I / O ports 13b EDLC 14b, 15b, 16b, B3, B4, B5, B6, B7, B8, B9, B21, B22 Batteries 17b PV equipment 18a, 31 DC / AC converter 18b load 19, 110, 210, 310, 410 EMS 32 Power system 100, 100A, 200, 200A, 200B, 300, 300A, 400 Power Network 101 Connection Line N1, N2, N3, N4, N5, N6, N7, N8, N9, N10, N11, N12, N13, N21, N22 nodes P1, P2, P3, P4, P5, P6, P7, P7A, P8, P9, P10, P10A, P11, P12, P12A, P13, P14, P15, P16, P17, P17A, P1 8, P19, P20, P21, P22, P23, P31, P32, P33, P41, P42, P43, P51, P52, P53, P61, P62, P63, P64, P65, P66 power path T11, T12, T13, T14, T21, T22, T23, T24, T31, T32, T33, T34, T41, T42, T43, T44, T51, T52, T53, T54, T61, T62, T63, T64, T65, T71, T72, T73, T74, T81, T82, T83, T91, T92, T93, T101, T102, T103, T104, T111, T121, T122, T123, T131, T132, T133, T211, T212, T213, T221, T222, T223, T224 Power Port

Claims

1. a plurality of power routers each having a plurality of power ports capable of inputting and outputting DC power, each of which converts power inputted from any of the plurality of power ports and outputs the converted power from at least one other power port; a plurality of interconnection lines that connect the plurality of power routers in a grid shape via the power ports; A power device that consumes or supplies power and is connected to a power port of at least one of the plurality of power routers that is not connected to the tie line; At least one of the plurality of power ports of each of the plurality of power routers is set as a market port in which characteristics of input or output DC power are not controlled, and among the plurality of power ports of each of the plurality of power routers, power ports other than the at least one power port set as the market port are set as control ports in which characteristics of input or output DC power are controlled.

1. An electric power network comprising:

2. At least one of the output ports is connected to a power storage device capable of storing and discharging DC power. The power network of claim 1 .

3. At least one of the normal ports of the plurality of power routers is connected to a constant voltage control port, which is set as a power port in which a voltage of input or output DC power is controlled to be constant within a predetermined range, among the plurality of power ports of at least one of the other power routers.

3. A power network according to claim 1 or 2.

4. At least one of the market ports of the power router having the voltage constant control port connected to the market port is connected to a power storage device capable of storing and discharging DC power.

4. The power network of claim 3.

5. At least one of the power ports of the plurality of power routers is a constant voltage control port set as a power port where the voltage of the input or output DC power is controlled to be constant within a predetermined range, and the constant voltage control port is connected to a constant current control port set as a power port where the current of the input or output DC power is controlled to be constant within a predetermined range among the plurality of power ports of the other power routers. A power network according to any one of claims 1 to 4.

6. A control unit for controlling the operation of at least one of the plurality of power routers. A power network according to any one of the preceding claims.

7. The control unit alternately switches at least one power port of the at least one power router between the normal port and a control port set as a power port where a characteristic of input or output DC power is controlled.

7. The power network of claim 6.

8. Each of the plurality of power ports of the at least one power router is connected to each of a plurality of power storage devices capable of storing and discharging DC power; The control unit switches the power port connected to each of the plurality of power storage devices between a normal port and a control port according to a charging state of each of the plurality of power storage devices.

8. A power network according to claim 6 or 7.

9. The control unit switches the power port connected to a power storage device, among the plurality of power storage devices, whose indicator indicating a charging state is close to an upper limit value or a lower limit value, from a market port to a control port.

9. The power network of claim 8.

10. The control unit controls the operation of at least two of the plurality of power routers. A power network according to any one of claims 6 to 9.

11. The control unit stops operation of a power router related to a power port to be connected by a tie line among the respective power ports of the at least two power routers, and maintains operation of a power router related to a power port other than the power port to be connected.

11. The power network of claim 10.

12. When the power port to be connected is a market port, the control unit stops an operation of a power router related to the market port and sets at least one of the power ports other than the power port to be connected to the market port.

12. The power network of claim 11.

13. When it is determined that a failure occurs in at least one of the plurality of connection lines and that the power port connected to the connection line where the failure occurs is a market port, the control unit switches at least one of the other power ports of the power router having the market port to the market port. A power network according to any one of claims 10 to 12.

14. The control unit switches a power port of another power router connected to a tie line connected to the power port switched to a normal port to a constant voltage control port if the power port is not a constant voltage control port.

14. The power network of claim 13.

15. A method for modifying an electricity network, comprising the steps of: The power network includes a plurality of power routers having a plurality of power ports capable of inputting and outputting DC power, the plurality of power routers converting power input from at least one of the plurality of power ports and outputting the converted power from at least one other power port, a plurality of interconnection lines connecting the plurality of power routers in a grid-like manner via the power ports, and a power device that consumes or supplies power and is connected to a power port of at least one of the plurality of power routers that is not connected to the interconnection lines, wherein at least one of the plurality of power ports of each of the plurality of power routers is set as a market port in which characteristics of the input or output DC power are not controlled, and among the plurality of power ports of each of the plurality of power routers, power ports other than the at least one power port set as the market port are set as control ports in which characteristics of the input or output DC power are controlled, Stopping the operation of a power router related to a power port to be connected by a tie line among the power ports of at least two of the plurality of power routers, and maintaining the operation of a power router related to a power port other than the power port to be connected; An additional power router is connected to the power port to be connected via a connection line. A method for modifying an electric power network, comprising:

16. When the power port to be connected is a market port, the operation of a power router related to the market port is stopped, and at least one of the power ports other than the power port to be connected is set to a market port. The method for modifying a power network according to claim 15.

17. A method for modifying an electricity network, comprising the steps of: The power network includes a plurality of power routers having a plurality of power ports capable of inputting and outputting DC power, the plurality of power routers converting power input from at least one of the plurality of power ports and outputting the converted power from at least one other power port, a plurality of interconnection lines connecting the plurality of power routers in a grid-like manner via the power ports, and a power device that consumes or supplies power and is connected to a power port of at least one of the plurality of power routers that is not connected to the interconnection lines, wherein at least one of the plurality of power ports of each of the plurality of power routers is set as a market port in which characteristics of the input or output DC power are not controlled, and among the plurality of power ports of each of the plurality of power routers, power ports other than the at least one power port set as the market port are set as control ports in which characteristics of the input or output DC power are controlled, When a fault occurs in at least one of the plurality of connection lines and it is determined that the power port connected to the connection line where the fault occurs is a market port, at least one of the other power ports of the power router having the market port is switched to the market port. A method for modifying an electric power network, comprising:

18. If the power port of another power router connected to the tie line connected to the power port switched to the normal port is not a constant voltage control port, the power port is switched to a constant voltage control port. The method for modifying a power network according to claim 15.

19. A method for modifying an electricity network, comprising the steps of: the power network includes a plurality of power routers having a plurality of power ports capable of inputting and outputting DC power, the plurality of power routers converting power input from at least one of the plurality of power ports and outputting the converted power from at least one other power port; a plurality of interconnection lines connecting the plurality of power routers in a grid-like manner via the power ports; and a power device that consumes or supplies power and is connected to a power port of at least one of the plurality of power routers that is not connected to the interconnection lines, wherein at least one of the plurality of power ports of each of the plurality of power routers is set as a market port in which characteristics of input or output DC power are not controlled, and among the plurality of power ports of each of the plurality of power routers, power ports other than the at least one power port set as the market port are set as control ports in which characteristics of input or output DC power are controlled, and each of the plurality of power ports of the at least one power router is connected to each of a plurality of power storage devices capable of storing and releasing DC power, The power port connected to each of the plurality of power storage devices is switched between a normal port and a control port in accordance with a charging state of each of the plurality of power storage devices. How to change the electricity network.

20. The power port connected to a power storage device, among the plurality of power storage devices, whose indicator indicating a charging state is close to an upper limit value or a lower limit value is switched from a market port to a control port.

20. The method of modifying a power network according to claim 19.

Images