JP2023094759A - power system - Google Patents

Abstract

To provide a power system capable of continuing power supply to each load as much as possible at the time of autonomous operation.SOLUTION: A power system S1 to which a plurality of loads L1 to Ln are connected can perform autonomous operation. The power system S1 comprises: a storage battery 3 capable of supplying power to the plurality of loads L1 to Ln; a power source 1 capable of supplying power to the plurality of loads L1 to Ln; and an autonomous operation control unit 5 for performing control of the autonomous operation. For each of the plurality of loads L1 to Ln, a degree of importance showing order of priority of power supply in the autonomous operation is set. During the autonomous operation, the autonomous operation control unit 5 performs switching between a connection state and a cut-off state on each of power supply paths to the plurality of loads L1 to Ln on the basis of a charging rate of the storage battery 3, power which the power source 1 can supply, and respective degrees of importance of the plurality of loads L1 to Ln.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to power systems.

2. Description of the Related Art Conventionally, there is a power system that is connected to a power system and supplies electric power obtained from the power system to a load. Further, some electric power systems are disconnected from the electric power system and perform self-sustained operation when there is an abnormality in the electric power system (for example, during a power outage). A power system that performs self-sustained operation includes distributed power sources, and supplies power obtained from the distributed power sources to loads during self-sustained operation without being supplied with power from the power system. As a result, power can be supplied to the load even when there is an abnormality in the power system. For example, Patent Literature 1 discloses a power system that performs self-sustained operation. The power system described in Patent Literature 1 includes a battery as a distributed power supply, and supplies power to a load by discharging the battery during self-sustained operation. At this time, the number of loads to which power is supplied is changed according to the state of charge (SoC) of the battery.

WO2020/230264

In the configuration described in Patent Document 1, only the battery supplies power to the load during self-sustained operation, and when the charging rate of the battery becomes a predetermined threshold (the third threshold in Patent Document 1) or less, each Power to the load is cut off.

The present disclosure has been conceived in view of the above circumstances, and an object thereof is to provide a power system capable of continuing power supply to each load as much as possible during self-sustained operation.

A power system of the present disclosure is a power system that is connected to a plurality of loads and is capable of self-sustaining operation, comprising: a storage battery capable of supplying power to the plurality of loads; a power source capable of supplying power to the plurality of loads; a self-sustaining operation control unit that controls the self-sustaining operation, wherein an importance level indicating a priority of power supply during the self-sustaining operation is set for each of the plurality of loads, and the self-sustaining operation control During the self-sustained operation, the unit connects each power supply path to the plurality of loads based on the charging rate of the storage battery, the suppliable power of the power source, and the degree of importance of each of the plurality of loads. switch to turn on or shut off.

In a preferred embodiment of the power system, the islanded operation control unit estimates the current suppliable power of the power source based on the current state of the power source.

In a preferred embodiment of the power system, the self-sustained operation control unit estimates future suppliable power of the power source based on a change schedule of the state of the power source.

In a preferred embodiment of the electric power system, a storage battery charge/discharge control section for charging and discharging the storage battery is further provided, and the power source, during the self-sustained operation, is based on the output voltage of the storage battery charge/discharge control section. , the plurality of loads includes the most important load with the highest degree of importance, the isolated operation control unit controls that the suppliable power is lower than the power consumption of the most important load, and When the charging rate of the storage battery becomes equal to or less than a first threshold, the self-sustained operation is suspended while only a part of the storage battery charge/discharge control unit is continued, and the first threshold is set to a part of the storage battery charge/discharge control unit. It is a value corresponding to the operation continuation lower limit value for continuing to operate only the part.

In a preferred embodiment of the power system, when the suppliable power becomes equal to or greater than a second threshold value based on the power consumption of the most important load in a state in which the islanded operation is suspended, the islanded operation control unit: Resume the self-sustaining operation.

According to the power system of the present disclosure, each power supply path to a plurality of loads is switched between a connected state and a disconnected state in consideration of the charging rate of the storage battery and the power that can be supplied by the power source. Therefore, it is possible to continue supplying power to each load as much as possible according to the state of the power source during the self-sustained operation.

It is a figure which shows the whole structural example which shows an electric power system. It is a figure which shows the basic processing of self-sustaining operation control which a self-sustaining operation control part performs. FIG. 10 is a diagram showing suspension processing of self-sustained operation control performed by the self-sustained operation control unit;

Preferred embodiments of the power system of the present disclosure will be described below with reference to the drawings. Below, the same reference numerals are given to the same or similar components, and overlapping descriptions are omitted.

FIG. 1 shows an example of the overall configuration of a power system S1 according to this embodiment. A power system S1 includes a plurality of loads L1 to Ln, a plurality of switches SW1 to SWn, a plurality of power sources 1, a plurality of power control devices 2, a storage battery 3, a storage battery power conditioner 4 (hereinafter referred to as "storage battery PCS4"), and An interconnection board C1 is provided (n is an integer equal to or greater than 2). Moreover, in electric power system S1, storage battery PCS4 contains the self-sustaining operation control part 5. FIG. In FIG. 1, thick connection lines are power lines, and thin connection lines are signal lines.

When the power system S1 is connected to the power system K, it performs grid-connected operation. On the other hand, the electric power system S1 is disconnected from the electric power system K and performs self-sustained operation (non-system-interconnected operation) when the electric power system K fails or has an abnormality. FIG. 1 shows a state in which the power system S1 is disconnected from the power system K. As shown in FIG. The electric power system S1 selectively switches to which of the plurality of loads L1 to Ln power is to be supplied during self-sustained operation. The self-sustained operation of the electric power system S1 is controlled by the self-sustained operation control unit 5 .

A plurality of loads L1 to Ln are connected to an interconnection board C1 via a plurality of switches SW1 to SWn, respectively. The i-th (i=integer from 1 to n) load Li is connected to the interconnection board C1 via the i-th switch SWi. The plurality of switches SW1 to SWn are capable of communicating with a self-sustaining operation control unit 5, which will be described later, and are switched between a connected state (on) and an open state (off) by a switching signal input from the self-sustaining operation control unit 5. . When the switch SWi is in the connected state, the power supply path from the interconnection board C1 to the load Li is connected, and power is supplied from the interconnection board C1 to the load Li. On the other hand, when the switch SWi is in an open state, the power supply path from the interconnection board C1 to the load Li is interrupted, and power is not supplied to the load Li. FIG. 1 shows an example in which the switches SW1 to SWn are all in the connected state, and when the switches SW1 to SWn are in the open state, the state is shown by the chain double-dashed lines in FIG. Each of the plurality of switches SW1 to SWn is, for example, a vacuum circuit breaker. In the electric power system S1, power is selectively supplied to a plurality of loads L1 to Ln by self-sustained operation control of the self-sustained operation control unit 5. FIG. Hereinafter, among the plurality of loads L1 to Ln, the load to which power is supplied during the self-sustaining control is referred to as the closed load Lo, and the load to which power is not supplied is referred to as the open load Lx. Further, among the plurality of switches SW1 to SWn, the one connected to the applied load Lo is called the switch SWo, and the one connected to the open load Lx is called the switch SWx.

The interconnection board C1 has a power distribution function and a system interconnection function (for example, an interconnection protection function, an FRT function, a reverse power flow limit function, a voltage adjustment function, a constant power factor control, etc.). In the power distribution function, the interconnection board C1 supplies input power to multiple loads L1 to Ln. In addition, in the power distribution function, the interconnection board C1 distributes the input power to the storage battery PCS4 and a part of the plurality of power control devices 2 (EV (Electric Vehicle) charger/discharger 22 described later) as necessary. supply each. In the grid interconnection function, for example, the interconnection board C1 disconnects the power system S1 from the power system K when it detects a power outage in the power system K. In addition, in the grid interconnection function, the interconnection board C1 connects the power system S1 to the power system K when the power system K recovers from the power failure.

A plurality of power sources 1 and storage batteries 3 are each capable of supplying power to a plurality of loads L1 to Ln. In a power system S1, multiple power sources 1 include a solar cell 11, an electric vehicle 12 and a generator 13. The solar cell 11 generates electric power by converting light energy such as sunlight into electrical energy (electric power). The electric vehicle 12 runs on electric power stored in an internal battery. In the present disclosure, charging and discharging of the electric vehicle 12 means charging and discharging of this built-in battery. The generator 13 generates electric power by converting energy other than electric power into electric energy (electric power). The generator 13 includes, for example, a hydraulic power generator using a water turbine, a wind power generator using a windmill, an internal combustion power generator (for example, a diesel generator) using an internal combustion engine (for example, a diesel engine), and the like. The storage battery 3 can be repeatedly charged and discharged, and is, for example, a secondary battery or a capacitor.

The plurality of power control devices 2 respectively control the plurality of power sources 1 . Each power control device 2 is connected between the interconnection board C<b>1 and each power source 1 . Each power control device 2 can communicate with a storage battery PCS4 (self-sustained operation control unit 5). In the example shown in FIG. 1 , the multiple power control devices 2 include a solar PCS 21 , an EV charger/discharger 22 and a generator controller 23 .

The solar PCS 21 controls the output of the solar cell 11 . The solar PCS 21 includes a solar power generation controller 211 . The solar power generation control unit 211 is electrically connected between the solar cell 11 and the interconnection board C1. The photovoltaic power generation control unit 211 outputs the power generated by the photovoltaic cell 11 to the interconnection board C1. Although one solar cell 11 is connected to one solar PCS 21 in the example shown in FIG. 1 , a plurality of solar cells 11 may be connected to one solar PCS 21 .

The EV charger/discharger 22 performs charge/discharge control of the electric vehicle 12 . EV charger/discharger 22 includes an EV charge/discharge controller 221 . The EV charging/discharging control unit 221 is electrically connected between the electric vehicle 12 and the interconnection board C1. The EV charging/discharging control unit 221 discharges the electric vehicle 12 by outputting the electric power accumulated in the electric vehicle 12 to the interconnection board C1, and outputs the electric power supplied from the interconnection board C1 to the electric vehicle 12. Thus, the electric vehicle 12 is charged. In the example shown in FIG. 1, one electric vehicle 12 is connected to one EV charger/discharger 22, but a plurality of electric vehicles 12 are connected to one EV charger/discharger 22. good too.

The generator controller 23 controls the output of the generator 13 . The generator controller 23 includes a generator control section 231 . The generator control unit 231 is electrically connected between the generator 13 and the interconnection board C1. The generator control unit 231 outputs the electric power generated by the generator 13 to the interconnection board C1. The generator controller 23 may be configured to operate the generator 13 only during the isolated operation of the power system S1, or operate the generator 13 during both the isolated operation and the grid-connected operation of the power system S1. It may be configured to operate.

Although illustration is omitted, the photovoltaic power generation control unit 211, the EV charge/discharge control unit 221, and the generator control unit 231 each include at least an inverter circuit, a control circuit, and a communication circuit. The inverter circuit performs power conversion in each power control device 2 . The control circuit controls the inverter circuit. The communication circuit communicates with the self-sustained operation control unit 5 .

The storage battery PCS4 performs charge/discharge control of the storage battery 3 and independent operation control of the electric power system S1. Storage battery PCS4 operates using the electric power accumulated in storage battery 3 . Storage battery PCS4 includes storage battery charge/discharge control unit 411 and self-sustained operation control unit 5 .

The storage battery charge/discharge control unit 411 is electrically connected between the storage battery 3 and the interconnection board C1. The storage battery charge/discharge control unit 411 discharges the storage battery 3 by outputting the power accumulated in the storage battery 3 to the interconnection board C1, and outputs the power supplied from the interconnection board C1 to the storage battery 3. 3 charging. In the example shown in FIG. 1 , one storage battery 3 is connected to one storage battery charge/discharge control unit 411 , but a plurality of storage batteries 3 are connected to one storage battery charge/discharge control unit 411 . good too. Although not shown, the storage battery charge/discharge control unit 411 includes at least an inverter circuit, a control circuit, and a communication circuit. The inverter circuit performs power conversion in the storage battery PCS4. The control circuit controls the inverter circuit. The communication circuit communicates with the self-sustained operation control unit 5 .

When the power system S1 is disconnected from the power grid K, the self-sustained operation control unit 5 controls self-sustained operation. The self-sustained operation control unit 5 does not control self-sustained operation when the electric power system S1 is interconnected. The isolated operation control unit 5 determines whether or not the power system S1 has been disconnected from the power system K based on information from the interconnection board C1, for example. The self-sustained operation control unit 5 is provided in the storage battery PCS4, and controls the storage battery charge/discharge control unit 411 so that the storage battery PCS4 becomes a voltage source during self-sustained operation. In the self-sustained operation control, the self-sustained operation control unit 5 switches between the connected state and the open state of each of the switches SW1 to SWn, and selectively cuts off the power supply path from the interconnection board C1 to each load L1 to Ln. do. In other words, in the self-sustaining operation control, the self-sustaining operation control unit 5 divides the plurality of loads L1 to Ln into an on load Lo that supplies power and an open load Lx that does not supply power. At this time, the self-sustained operation control unit 5 uses the charging rate of the storage battery 3, the suppliable power of the plurality of power sources 1, and the information on the importance of each of the plurality of loads L1 to Ln, respectively. Sorting with the load Lx is performed.

The degrees of importance of the plurality of loads L1 to Ln are set in the self-sustained operation control unit 5 in advance or by user input. The importance is information indicating the order of priority of power supply to the loads L1 to Ln. The higher the importance, the more preferentially electric power is supplied during the self-sustained operation. That is, in the electric power system S1, during the self-sustained operation, the higher the importance, the more likely the power supply is continued, and the lower the importance, the more likely the power supply is interrupted. In this embodiment, load L1 has the highest importance, and load L1 is the most important load. Then, load L2, load L3, . Note that the plurality of loads L1 to Ln may have the same importance. For example, in a business office, the power supply for the main system in the office has a high degree of importance, followed by emergency lighting, workers' personal computers, ventilation equipment, air conditioning equipment, general lighting, elevators, etc., in descending order of importance. . Further, the importance of each load L1 to Ln is set for each load L1 to Ln, and the islanded operation control unit 5 acquires information on the importance of each load L1 to Ln from each load L1 to Ln. may

The charging rate of the storage battery 3 is obtained by communication from the storage battery charge/discharge control unit 411 . In an example where the self-sustained operation control unit 5 is installed in the storage battery PCS4, the self-sustained operation control unit 5 may directly acquire the charging rate of the storage battery 3 from the storage battery 3.

The suppliable power of each power source 1 is estimated based on information indicating the state of each power source 1 acquired through communication with each power control device 2 . In the power system S1, the isolated operation control unit 5 acquires information indicating the current state of each power source 1 (hereinafter referred to as "current data") by communicating with each power control device 2, and based on the acquired current state data to estimate the current suppliable power of each power source 1 . In addition, the isolated operation control unit 5 acquires information (hereinafter referred to as "transition prediction data") indicating future state change schedule (or change prediction) of each power source 1 through communication with each power control device 2, Future suppliable power of each power source 1 is estimated based on the obtained transition prediction data. For example, the self-sustained operation control unit 5 acquires the following information for each power source 1 as current data or transition prediction data, and estimates the current suppliable power and future suppliable power of each power source 1 .

The self-sustained operation control unit 5 acquires information on the current solar radiation intensity (for example, the measured value of the pyranometer) at the installation location of the solar cell 11 as the current state data of the solar cell 11 through communication with the solar PCS 21 . Then, the current power generation capacity of the solar cell 11 is estimated using the acquired current state data of the solar cell 11 . In addition, the self-sustained operation control unit 5 communicates with the solar power PCS 21 to obtain information about future changes in solar radiation intensity (for example, weather forecast, past solar radiation information, season, etc.) at the installation location of the solar cell 11. It is acquired as the change prediction data of the battery 11 . Then, the future power generation capacity of the solar cell 11 is estimated using the obtained shift prediction data of the solar cell 11 . The specification information (for example, maximum output and conversion efficiency) of the solar cell 11 used when estimating the power generation capacity may be obtained from the solar PCS 21 or set in the self-sustained operation control unit 5 in advance. You can leave it. Further, the acquisition locations of the current data of the solar cell 11 and the predicted change data of the solar cell 11 are not limited to the above examples. For example, the self-sustained operation control unit 5 may acquire the current solar radiation intensity directly from a pyranometer, may acquire weather forecasts and past solar radiation information from the Internet or other management devices, and may acquire seasonal information. may be acquired (determined) from a timer (not shown) of the self-sustained operation control unit 5 .

The autonomous operation control unit 5 communicates with the EV charger/discharger 22 to obtain information such as whether the electric vehicle 12 is connected to the EV charger/discharger 22 and the charging rate of the electric vehicle 12 as current data of the electric vehicle 12. get. Then, using the obtained current state data of the electric vehicle 12, the current dischargeable amount of the electric vehicle 12 is estimated. Also, the self-sustained operation control unit 5 acquires information such as a connection schedule of the electric vehicle 12 as transition prediction data of the electric vehicle 12 through communication with the EV charger/discharger 22 . Then, the future dischargeable amount of the electric vehicle 12 is estimated using the acquired displacement prediction data of the electric vehicle 12 . The specification information of the electric vehicle 12 used when estimating the dischargeable amount (for example, the rated discharge capacity and the discharge C rate) may be obtained from the EV charger/discharger 22, or may be sent to the self-sustained operation control unit 5. It may be set in advance. Further, the acquisition locations of the current data of the electric vehicle 12 and the predicted change data of the electric vehicle 12 are not limited to the above examples. For example, the self-sustained operation control unit 5 may acquire information on whether the electric vehicle 12 is connected or not and information on the scheduled connection of the electric vehicle 12 from the Internet or other management device, or may obtain the charging rate of the electric vehicle 12 from the It may be obtained directly from the vehicle 12 .

The self-sustaining operation control unit 5 communicates with the generator controller 23 to determine the remaining amount of fuel if the generator 13 is an internal combustion generator, and the flow rate at the installation location of the water turbine if the generator 13 is a hydroelectric generator ( For example, the measured value of the flow meter), and if the generator 13 is a wind power generator, the information of the wind volume and wind speed at the installation location of the wind turbine (for example, the measured values of the anemometer and the anemometer) are used as the current data of the generator 13. get. Then, the current power generation capacity of the power generator 13 is estimated using the acquired current state data of the power generator 13 . In addition, the self-sustaining operation control unit 5 communicates with the generator controller 23 to determine whether the generator 13 will If the generator 13 is a wind power generator, the wind volume and wind speed at the location where the wind turbine is installed. Information on a change schedule (for example, weather forecast, past wind volume information and wind speed information, season, etc.) is acquired as change prediction data for the generator 13 . Then, the future power generation amount of the power generator 13 is estimated using the obtained change prediction data of the power generator 13 . The specification information (for example, maximum output, rated capacity, conversion efficiency, etc.) of the generator 13 used when estimating the amount of power that can be generated may be obtained from the generator controller 23, or the self-sustained operation control unit 5 may be set in advance. Further, the acquisition locations of the current data of the generator 13 and the predictive change data of the generator 13 are not limited to the above examples. For example, the self-sustaining operation control unit 5 may directly acquire the remaining amount of fuel from the internal combustion power generator, the flow rate from the flow meter, or the air volume and wind speed from the air flow meter and the anemometer. A change schedule for airflow, a change schedule for flow rate, or each change schedule for air volume and wind speed may be obtained from the Internet or other management devices.

During the self-sustained operation, the self-sustained operation control unit 5 is based on the charging rate of the storage battery 3, the suppliable power of the plurality of power sources 1, and the importance of the plurality of loads L1 to Ln. is comprehensively determined, and each power supply path to a plurality of loads L1 to Ln is switched between the connected state and the disconnected state.

In the example shown in FIG. 1, the self-sustained operation control unit 5 is provided in the storage battery PCS 4, but unlike this configuration, a plurality of power control devices 2 (solar PCS 21, EV charger/discharger 22, and generator control unit 2) 23). That is, any one of the solar PCS 21, the EV charger/discharger 22, and the generator controller 23 may perform self-sustained operation control. In this case, instead of the storage battery PCS4, the power control device 2 provided with the self-sustained operation control unit 5 operates as a voltage source. Alternatively, the self-sustained operation control unit 5 may be configured as one device by itself.

2 and 3 are flow charts showing self-sustained operation control performed by the self-sustained operation control unit 5. FIG. FIG. 2 shows an example of a basic process of self-sustained operation control, and FIG. 3 shows an example of a pause process that is performed in parallel with the basic process shown in FIG. The self-sustained operation control unit 5 repeatedly continues each process shown in FIGS. 2 and 3 until the system power supply of the electric power system S1 is turned off.

First, with reference to FIG. 2, the basic processing of self-sustained operation control will be described. While the power system S1 is disconnected from the power system K, the self-sustained operation control unit 5 repeatedly executes the basic processing shown in FIG. 2 every 1 sec to 1 min, for example. Note that the isolated operation control unit 5 does not perform the basic processing shown in FIG. 2 while the power system S1 is connected to the power system K. The isolated operation control unit 5 determines whether the power system S1 is connected to the power system K or disconnected from the power system K based on the information from the interconnection board C1. The control cycle of the basic processing is not limited to the numerical example (1 sec to 1 min) described above. Also, the self-sustained operation control unit 5 may be triggered by some process or change instead of time. For example, the self-sustained operation control unit 5 may execute the basic process each time the charging rate of the storage battery 3 is checked.

As shown in FIG. 2 , in the basic process of self-sustained operation control, the self-sustained operation control unit 5 first acquires transition prediction data of the power source 1 from each power control device 2, and uses the acquired transition prediction data to determine the future power supply. The available power is estimated (S101). Next, the self-sustained operation control unit 5 acquires the current data of the power source 1 from each power control device 2, and estimates the current suppliable power from the acquired current data (S102). Note that the order of step S101 and step S102 may be reversed.

Next, the self-sustained operation control unit 5 calculates the suppliable power for each predetermined time period and creates a suppliable power schedule (S103). The division of the time period is not particularly limited, but may be, for example, 10 minutes, 30 minutes, 1 hour, 2 hours, 3 hours, or the like. The suppliable power for each time period may be the total value of the plurality of power sources 1 or the individual value for each of the plurality of power sources 1 . A period for creating a schedule of suppliable power is not particularly limited, but may be 24 hours, one week, one month, or the like. In creating the schedule of suppliable power in step S103, operating conditions for each power source 1 may be appropriately set. For example, if the generator 13 is a diesel generator, the generator 13 generates power when the solar cell 11 cannot generate power (for example, at night) or when the amount of power generated by the solar cell 11 is low (for example, on rainy days). Limited to Discharging of the electric vehicle 12 is prohibited if the charging rate of the electric vehicle 12 is equal to or less than a predetermined value.

Next, the self-sustaining operation control unit 5 determines the power consumption and importance of the plurality of loads L1 to Ln, the schedule of the suppliable power (current suppliable power and future suppliable power transition, etc.), the charging rate of the storage battery 3 and the discharge amount and discharge duration calculated from the discharge C rate and the like are comprehensively determined, and the plurality of loads L1 to Ln are divided into an input load Lo that supplies power and an open load Lx that does not supply power. Select (S104). At this time, the self-sustained operation control unit 5 selects whether each of the loads L1 to Ln should be the closed load Lo or the released load Lx at this time. At this time, in step S104, the self-sustained operation control unit 5 may further schedule each of the loads L1 to Ln as the applied load Lo or the released load Lx for each predetermined time period. . By scheduling the input load Lo and the released load Lx for each predetermined time slot in this way, the user can confirm the future availability of each load L1 to Ln by informing the user of the scheduling information. can do.

In the sorting in step S104, the power supply to the load L1 with the highest degree of importance is continued as long as possible. That is, the load L1 is set to be the input load Lo for as long a time as possible. Further, in the sorting in step S104, the number of loads Lo to be applied may be reduced to intentionally make the power consumption lower than the suppliable power, and the surplus power may be used for charging the storage battery 3 or charging the electric vehicle 12. . For example, in preparation for when the solar cell 11 cannot generate power (for example, at night) or when the amount of power generated by the solar cell 11 is low (for example, on rainy days), each charging rate of the storage battery 3 and the electric vehicle 12 is secured. , the input load Lo. Further, in the selection of the applied load Lo and the released load Lx in step S104, among the plurality of loads L1 to Ln, those having a predetermined degree of importance or less may be uniformly assigned to the released load Lx during the self-sustained operation.

In step S104, the self-sustained operation control unit 5 selects, for example, whether to use the applied load Lo or the released load Lx as follows. It confirms the future supplyable power of the solar cell 11 and the future supplyable power of the generator 13 from the current time and the schedule of the supplyable power, and determines how many more hours the storage battery 3 and the electric vehicle 12 can discharge. Calculate whether driving is required. Alternatively, the future suppliable power of the solar cell 11 is confirmed, and how many more hours the solar cell 11 can generate power is calculated. Then, from the charging rate of the storage battery 3 and the charging rate of the electric vehicle 12, how many kW can be discharged until the start of power generation of the solar cell 11 is calculated. Calculate how many kW of discharge can continue the self-sustained operation until the start of power generation, and determine the input load Lo based on the calculated data (the load that is not the input load Lo is the open load Lx).

Next, the self-sustained operation control unit 5 switches the switches SW1 to SWn based on the sorting result in step S104 (S105). Specifically, the self-sustained operation control unit 5 connects the switch SWo to which the applied load Lo is connected, which is selected as the applied load Lo from the selection result of step S104. A power supply path from C1 to the input load Lo is connected. In addition, the isolated operation control unit 5 opens the switch SWx to which the open load Lx is connected to the one selected as the open load Lx, and supplies power from the interconnection board C1 to the open load Lx. block the road.

In the electric power system S1, by performing the above-described basic processing of the self-sustained operation control, it is possible to appropriately change the operation method of the self-sustained operation control by the schedule of the suppliable power and the selection of the input load Lo and the released load Lx. . For example, by reducing the number of input loads Lo and by operating the power supply from each power source 1 as the main power supply to assist the discharge of the storage battery 3, the power of the most important load (the load L1 with the highest importance) Self-sustained operation can be operated so that the supply time is continued longer and at the same time the power supply is continued in order of importance as much as possible. Further, by increasing the number of applied loads Lo and actively supplying power from each power source 1 and discharging the storage battery 3, self-sustained operation can be operated so as to increase the number of applied loads Lo.

Next, with reference to FIG. 3, the suspension processing of self-sustained operation control will be described. As described above, the suspension processing of the self-sustained operation control is performed in parallel with the basic processing shown in FIG. However, the basic processing shown in FIG. 2 is interrupted while part of the pause processing shown in FIG. 3 is being executed.

As shown in FIG. 3, in the suspension process of the islanded operation control, the islanded operation control unit 5, in a state where only the load L1, which is the most important load, is the input load Lo, the current suppliable power Pt is the most important load. (S201). If it is determined in step S201 that it is not less than (Pt≧PL1) (S201: NO), the determination in step S201 is repeated. On the other hand, if it is determined in step S201 that it has fallen below (Pt<PL1), then it is determined whether or not the charging rate of the storage battery 3 is equal to or less than a predetermined first threshold (S202). This first threshold is a value for preventing the storage battery PCS4, which is operated by the power of the storage battery 3, from completely stopping for a predetermined period of time. It is set based on the amount of electric power (operation continuation lower limit) required to operate the unit 5 continuously for a predetermined time. In this embodiment, the above-mentioned first threshold value, that is, the lower limit value of continued operation is, for example, 5%. In addition, in the configuration in which the self-sustained operation control unit 5 is not provided in the storage battery PCS4, the above-mentioned first threshold is the operation continuation lower limit for operating the communication circuit in the storage battery charge/discharge control unit 411 continuously for a predetermined period. value. When it is determined in step S202 that it is not equal to or less than the first threshold (greater than the first threshold) (S202: NO), the storage battery 3 is discharged and power is supplied to the load L1. And it returns to determination of step S201. On the other hand, when it is determined in step S202 that it is equal to or less than the first threshold value (S202: YES), self-sustained operation is suspended (S203). Suspension of the self-sustained operation stops power supply from the storage battery 3 to the inverter circuit and the control circuit of the storage battery charge/discharge control unit 411, for example. At this time, the power supply from the storage battery 3 to the communication circuit of the storage battery charge/discharge control unit 411 and the self-supporting operation control unit 5 is not stopped. When the self-sustained operation is suspended in step S203, the basic processing shown in FIG. 2 is suspended.

Next, in step S203, it is determined whether or not the current suppliable power Pt has reached or exceeded a second threshold value based on the power consumption of the load L1, which is the most important load, during suspension of the self-sustained operation. Specifically, as shown in FIG. 3, the isolated operation control unit 5 determines whether or not the current suppliable power Pt is greater than the power consumption PL1 of the load L1, which is the most important load, by a certain value α or more. Determine (S204). That is, in the present embodiment, the above-described second threshold is the sum of the power consumption PL1 and the constant value α, and the self-sustained operation control unit 5 determines whether or not Pt≧PL1+α in step S204. Note that the constant value α may include 0 (zero). In this case, in step S204, the self-sustained operation control unit 5 determines whether or not the current suppliable power Pt has become equal to or greater than the power consumption PL1. If it is determined in step S204 that the value is not equal to or greater than the second threshold value (Pt<PL1+α) (S204: NO), the suspension of self-sustained operation is continued, and the determination in step S204 is repeated. On the other hand, if it is determined in step S204 that the value is equal to or greater than the second threshold (Pt≧PL1+α) (S204: YES), the self-sustained operation control unit 5 transfers from the storage battery 3 to the inverter circuit and the control circuit of the storage battery charge/discharge control unit 411. restart the power supply to resume self-sustaining operation. For example, when the electric vehicle 12 is newly connected to the EV charger/discharger 22 or when the solar radiation intensity on the solar cell 11 increases, the current suppliable power Pt increases. When the self-sustained operation control unit 5 resumes the self-sustained operation, the basic processing shown in FIG. 2 is also resumed. Then, the self-sustained operation control unit 5 returns to the determination of step S201.

The actions and effects of the electric power system S1 are as follows.

A power system S1 comprises a power source 1 capable of supplying power to a plurality of loads L1-Ln. The power source 1 is, for example, a solar cell 11, an electric vehicle 12 or a generator 13. Then, during the self-sustained operation of the electric power system S1, the self-sustained operation control unit 5 selects a plurality of Each power supply path to the loads L1 to Ln is switched between a connected state and a disconnected state. According to this configuration, even if the charging rate of the storage battery 3 has decreased to such an extent that the storage battery 3 cannot be discharged, the self-sustained operation can be continued as long as the power source 1 can supply power. In addition, the power system S1 can continue to supply power to each load as much as possible according to the state of the power source 1 during self-sustained operation.

In the power system S1, the self-sustained operation control unit 5 acquires information (current state data) indicating the current state of each power source 1, and estimates the current suppliable power of each power source 1 from this current state data. In addition, the self-sustained operation control unit 5 acquires information (transition prediction data) indicating the future state change schedule of each power source 1, and estimates the future suppliable power of each power source 1 from this transition prediction data. . Then, the self-sustained operation control unit 5 creates a schedule of suppliable power using the present suppliable power and the future suppliable power of each power source 1 . According to this configuration, the self-sustained operation control unit 5, when sorting the plurality of loads L1 to Ln into the applied load Lo to which power is supplied and the released load Lx to which power is supplied, determines the future suppliable power of each power source 1. It can be seasoned. As a result, the self-sustained operation control unit 5 can control the self-sustained operation while referring to the future suppliable power. It is possible to operate isolated operation so as to supply power to other loads L2 to Ln. Alternatively, for example, it is possible to operate self-sustained operation so that the number of input loads Lo to which power is supplied is increased. Therefore, the electric power system S1 can flexibly operate the self-sustained operation by controlling in consideration of the future suppliable electric power of each electric power source 1 .

In the power system S1, the current suppliable power Pt of the power source 1 is lower than the power consumption PL1 of the load L1, which is the most important load, and the charging rate of the storage battery 3 is below the first threshold (storage battery charge/discharge control unit 411 operation continuation lower limit value for continuously operating only the communication circuit)), the self-sustaining operation control unit 5 stops the inverter circuit and the control circuit of the storage battery charge/discharge control unit 411, and suspends self-sustaining operation. do. According to this configuration, overdischarge of the storage battery 3 due to auxiliary equipment loss of the storage battery PCS4 can be suppressed. As a result, after that, when the current suppliable power of the power source 1 becomes equal to or greater than the second threshold (the sum of the power consumption PL1 and the constant value α) based on the power consumption of the most important load (load L1), the power source 1 stops. Part of the self-sustained operation control unit 5 (inverter circuit and control circuit) that has been operating can be restarted, and self-sustained operation can be resumed. In other words, self-sustained operation can be automatically restarted without user's operation. Moreover, when the storage battery 3 is over-discharged, the storage battery PCS4 will be in an unrecoverable state. Therefore, since the storage battery PCS4 cannot charge the storage battery 3, the user needs to go to the installation location of the storage battery 3 and charge the storage battery 3 separately. In other words, stopping part of the storage battery charge/discharge control unit 411 to suppress overdischarge of the storage battery 3 enables the electric power system S1 to quickly return to self-sustained operation from a state where self-sustained operation has been suspended.

In the electric power system S1, when the power consumption transition schedule of each of the loads L1 to Ln is known, the islanded operation control unit 5 may further consider the power consumption transition schedule of each of the loads L1 to Ln in the islanded operation control. . For example, when a plurality of loads L1 to Ln are installed in an office, some of the plurality of loads L1 to Ln (for example, lighting or a personal computer for personal use) are used during the daytime on weekdays and Power consumption fluctuates between weekday nights and holidays. On the other hand, some of the loads L1 to Ln (for example, the power supply of the main system) have constant power consumption regardless of weekdays or holidays. Considering such a transition schedule of the power consumption of each load L1 to Ln enables more flexible self-sustained operation.

In the electric power system S1, when the power outage schedule (planned parallel off from the electric power system K) is known from rolling power outages, the islanded operation control unit 5 may further consider the power outage schedule in the islanded operation control. Considering such a power outage schedule, the charging rate of the storage battery 3 can be increased, for example, at the time of system interconnection before the self-sustained operation. In addition, since the time until recovery from a power failure can be known, the discharge of the storage battery 3 can be utilized to the maximum.

In the power system S1, an example in which the self-sustaining operation control unit 5 is provided in the storage battery PCS4 is shown, but the self-sustaining operation control unit 5 includes a plurality of power control devices 2 (solar PCS 21, EV charger/discharger 22 and generator control 23). That is, any one of the solar PCS 21, the EV charger/discharger 22, and the generator controller 23 may perform self-sustained operation control. In this case, instead of the storage battery PCS4, the power control device 2 provided with the self-sustained operation control unit 5 operates as a voltage source. Alternatively, the self-sustained operation control unit 5 may be configured as one device by itself.

In the power system S1, an example including a plurality of power sources 1 was shown, but the number of power sources 1 may be one. For example, a configuration in which only the solar battery 11 is provided side by side with the storage battery 3, a configuration in which only the electric vehicle 12 is provided side by side, or a configuration in which only the power generator 13 is provided side by side may be employed.

In the electric power system S1, only the current suppliable electric power of each electric power source 1 may be considered to select the applied load Lo and the open load Lx. In this configuration, the self-sustained operation control unit 5 does not need to estimate the future suppliable power of each power source 1 or create a schedule of suppliable power. In the power system according to this modification, the power supplied from the power source 1 can be supplied to each load L1 to Ln during the self-sustained operation, so the charging rate of the storage battery 3 decreases to the extent that the storage battery 3 cannot be discharged. Even in such a case, the self-sustained operation can be continued while power can be supplied from the power source 1 . Also, in the power system according to the modification, it is possible to continue supplying power to each load as much as possible according to the state of the power source 1 during self-sustained operation.

In the electric power system S1, the current suppliable power may not be taken into consideration when creating a schedule of suppliable power. The power system according to this modification can also continue self-sustained operation while power can be supplied from the power source 1 . Also, in the power system according to the modification, it is possible to continue supplying power to each load as much as possible according to the state of the power source 1 during self-sustained operation. However, if the current available power is taken into account, the estimated value of the available power at the current time will be closer to the actual available power, so the error (excess or deficiency) in the available power will be suppressed. .

The power system according to the present disclosure is not limited to the above-described embodiments. The specific configuration of each part of the power system of the present disclosure can be modified in various ways.

S1: power system, 1: power source, 3: storage battery, 4: storage battery power conditioner (storage battery PCS), 5: independent operation control unit, 11: solar battery, 12: electric vehicle, 13: generator, 411: storage battery Charge/discharge control unit, K: power system, L1 to Ln, Li: load

Claims (5)

A power system in which a plurality of loads are connected and capable of independent operation,
a storage battery capable of supplying power to the plurality of loads;
a power source capable of supplying power to the plurality of loads;
a self-sustaining operation control unit that controls the self-sustaining operation;
with
For each of the plurality of loads, a degree of importance indicating the priority of power supply during the self-sustained operation is set,
The self-sustained operation control unit, during the self-sustained operation, controls each power supply path to the plurality of loads based on the charging rate of the storage battery, the suppliable power of the power source, and the importance of each of the plurality of loads. A power system that switches between a connected state and a disconnected state. 2. The power system according to claim 1, wherein said self-sustained operation control unit estimates current suppliable power of said power source based on a current state of said power source. 3. The electric power system according to claim 1, wherein said self-sustained operation control unit estimates future suppliable electric power of said electric power source based on a change schedule of the state of said electric power source. further comprising a storage battery charge/discharge control unit that charges and discharges the storage battery,
The power source supplies power based on the output voltage of the storage battery charge/discharge control unit during the self-sustained operation,
The plurality of loads includes the most important load with the highest importance,
When the suppliable power is lower than the power consumption of the most important load and the charging rate of the storage battery is equal to or lower than a first threshold value, the self-sustaining operation control unit operates only a part of the storage battery charge/discharge control unit. While continuing, suspending the self-sustaining operation,
The electric power system according to any one of claims 1 to 3, wherein the first threshold value is a value corresponding to an operation continuation lower limit value for continuing to operate only a part of the storage battery charge/discharge control unit. . 5. The self-sustained operation control unit restarts the self-sustained operation when the suppliable power becomes equal to or greater than a second threshold value based on the power consumption of the most important load while the self-sustained operation is suspended. Power system as described.

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