JP7629879B2 - Power system and control method - Google Patents

Description

The present invention relates to a power system and a control method.

In recent years, technology has been developed that uses energy storage devices as distributed power sources (e.g., Virtual Power Plants (VPPs)) to maintain the balance between power supply and demand in a power grid. In such cases, it is necessary to adjust the frequency of the power grid by using reverse flow power supplied from the facility to the power grid (hereinafter, "supply and demand adjustment"). To enable such supply and demand adjustment, technology has been proposed that divides regulated power sources into categories and transmits appropriate signals for each category (e.g., Patent Document 1).

Patent No. 6183576

When a facility receives a supply and demand adjustment request from an operator such as an AC (Aggregation Coordinator) or RA (Resource Aggregator), the facility is expected to execute specific control to control the energy storage device within the facility based on the frequency of the power grid in response to the supply and demand adjustment request. The facility reports the results of the specific control to the AC or RA.

In such cases, the facility must synchronize the time using a time server. The time synchronization method may be NTP (Network Time Protocol). For example, the time must be synchronized at least once an hour.

However, if the time is adjusted while the above-mentioned supply and demand adjustment is being performed, the timestamp attached to the result of the specific control may become discontinuous.

The present invention has been made to solve the above-mentioned problems, and aims to provide a power system and control method that can prevent the timestamps attached to the results of specific control from becoming discontinuous.

One aspect of the disclosure is an electric power system that includes a power storage device that executes specific control for controlling charging and discharging based on the frequency of a power grid, and a control device that controls the power storage device, and the control device stops a time adjustment function related to time adjustment that corrects the time managed by the control device using the time managed by a time server before the specific control, and resumes the time adjustment function after the specific control, and adjusts a timestamp attached to the result of the specific control when a parameter related to the time adjustment satisfies a specific condition.

One aspect of the disclosure is an electric power system that includes a power storage device that executes specific control for controlling charging and discharging based on the frequency of a power grid, and a control device that controls the power storage device, in which the control device sets, before the specific control, the suspension of a time adjustment function for correcting the time managed by the control device using the time managed by a time server in the power storage device, and sets, after the specific control, the resumption of the time adjustment function in the power storage device, and the power storage device adjusts a timestamp attached to the result of the specific control when a parameter related to the time adjustment satisfies a specific condition.

One aspect of the disclosure is a control method comprising the steps of: a control device that controls an energy storage device that executes specific control for controlling charging and discharging based on the frequency of a power grid, stopping a time adjustment function related to time adjustment that corrects the time managed by the control device using a time managed by a time server before the specific control; a step of the control device resuming the time adjustment function after the specific control; and a step of the control device adjusting a timestamp attached to the result of the specific control when a parameter related to the time adjustment satisfies a specific condition.

One aspect of the disclosure is a control method comprising the steps of: a control device that controls an energy storage device that executes specific control for controlling charging and discharging based on the frequency of a power grid, setting, before the specific control, a time adjustment function for correcting the time managed by the control device using a time managed by a time server, in the energy storage device to stop; a step of the control device setting, after the specific control, a time adjustment function for resuming, in the energy storage device; and a step of the energy storage device adjusting a timestamp attached to the result of the specific control when a parameter related to the time adjustment satisfies a specific condition.

The present invention provides an electric power system and a control method that can prevent discontinuity in the timestamps attached to the results of specific control.

FIG. 1 is a diagram showing a power management system 1 according to an embodiment. FIG. 2 is a diagram showing a facility 100 according to the embodiment. FIG. 3 is a diagram showing a power storage device 120 according to the embodiment. FIG. 4 is a diagram showing the EMS 160 according to the embodiment. FIG. 5 is a diagram for explaining frequency fluctuation adjustment according to the embodiment. FIG. 6 is a diagram for explaining the specific control according to the embodiment. FIG. 7 is a diagram for explaining option 1 according to the embodiment. FIG. 8 is a diagram for explaining option 2 according to the embodiment.

The following describes the embodiments with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, the drawings are schematic.

[Embodiment]
(Power Management System)
A power management system according to an embodiment will be described below. The power management system may be simply referred to as a power system.

As shown in FIG. 1, the power management system 1 has a facility 100. The power management system 1 may include a power management server 200 and may also include a time server 300.

Here, the facility 100 and the power management server 200 are configured to be able to communicate with each other via a network 11. The network 11 may include the Internet, a dedicated line such as a VPN (Virtual Private Network), or a mobile communication network.

The facility 100 is connected to the power grid 12 and may receive power from the power grid 12 or may supply power to the power grid 12. Power from the power grid 12 to the facility 100 may be referred to as forward flow power, purchased power, or demand power. Power from the facility 100 to the power grid 12 may be referred to as reverse flow power or sold power. In FIG. 1, facilities 100A to 100C are illustrated as examples of the facility 100.

Although not particularly limited, facility 100 may be a facility such as a residence, a facility such as a store, or a facility such as an office. Facility 100 may be an apartment building including two or more residences. Facility 100 may be a complex including at least two or more of the following facilities: residences, stores, and offices. Details of facility 100 will be described later (see FIG. 2).

The power management server 200 is managed by a business operator that manages power related to the power system 12. The business operator may be a power generation business operator, a power transmission and distribution business operator, or a retail business operator. The business operator may be a resource aggregator (hereinafter, RA), or an aggregation coordinator (AC) that manages the RA. The RA may be a business operator that adjusts the power supply and demand balance of the power system 12. The adjustment of the power supply and demand balance may include a transaction (hereinafter, negawatt trading) in which reduced power of the demand power (flow power) of the facility 100 is exchanged for value. The adjustment of the power supply and demand balance may include a transaction in which increased power of reverse flow power is exchanged for value. In the VPP, the RA may be a business operator such as a power generation business operator, a power transmission and distribution business operator, or a retail business operator.

The time server 300 is a server that manages the reference time for performing time adjustment in the power management system 1. Although not particularly limited, the time adjustment method may be NTP (Network Time Protocol). For example, the power storage device 120 or the EMS 160 may perform time adjustment periodically, or may perform time adjustment in response to a request from the power management server 200 (AC or RA). Time adjustment may be performed in a wireless environment based on standards such as IEEE802.11a/b/g/n/ac/ax, ZigBee, Wi-SUN, LTE, 5G, and 6G.

In the embodiment, communication between the power management server 200 and the EMS 160 is performed according to a first protocol. On the other hand, communication between the EMS 160 and the distributed power source (the solar cell device 110, the power storage device 120, or the fuel cell device 130) is performed according to a second protocol different from the first protocol. For example, the first protocol may be a protocol conforming to Open ADR (Automated Demand Response) or a unique dedicated protocol. For example, the second protocol may be a protocol conforming to ECHONET Lite (registered trademark), SEP (Smart Energy Profile) 2.0, KNX, or a unique dedicated protocol. Note that the first protocol and the second protocol may be different, and for example, even if both are unique dedicated protocols, they may be protocols created according to different rules. However, the first protocol and the second protocol may be protocols created according to the same rules.

(facility)
A facility according to an embodiment will be described below. As shown in Fig. 2, the facility 100 includes a solar cell device 110, a power storage device 120, a fuel cell device 130, a load device 140, and an EMS (Energy Management System) 160. The facility 100 may also include a measuring device 190.

The solar cell device 110 is a distributed power source that generates electricity in response to light such as sunlight. For example, the solar cell device 110 is composed of a PCS (Power Conditioning System) and a solar panel. Here, installation may mean connecting the solar cell device 110 to the power grid 12.

The energy storage device 120 is a distributed power source that charges and discharges power. For example, the energy storage device 120 is composed of a PCS and a storage cell. Here, installation may mean that the energy storage device 120 is connected to the power grid 12.

The fuel cell device 130 is a distributed power source that generates electricity using fuel. For example, the fuel cell device 130 is composed of a PCS and a fuel cell. Here, installation may mean that the fuel cell device 130 is connected to the power grid 12.

For example, the fuel cell device 130 may be a solid oxide fuel cell (SOFC; Solid Oxide Fuel Cell), a polymer electrolyte fuel cell (PEFC; Polymer Electrolyte Fuel Cell), a phosphoric acid fuel cell (PAFC; Phosphoric Acid Fuel Cell), or a molten carbonate fuel cell (MCFC; Molten Carbonate Fuel Cell).

The load device 140 is a device that consumes power. For example, the load device 140 may include an air conditioner that adjusts the temperature of a specific space in the facility 100, or a lighting device that adjusts the illuminance of a specific space in the facility 100. The load device 140 may include video equipment, audio equipment, a refrigerator, a washing machine, a personal computer, etc.

The EMS 160 manages the power for the facility 100. The EMS 160 may control the solar cell device 110, the power storage device 120, the fuel cell device 130, and the load devices 140. In the embodiment, the EMS 160 is illustrated as an example of a device that receives control commands from the power management server 200, but such a device may be referred to as a Gateway or simply as a control unit. To distinguish the EMS 160 from the power management server 200, the EMS 160 may be referred to as a Local EMS (LEMS), a Home EMS (HEMS), or a VPP controller. Details of the EMS 160 will be described later (see FIG. 4).

The measuring device 190 measures the forward flow power from the power system 12 to the facility 100. The measuring device 190 may also measure the reverse flow power from the facility 100 to the power system 12. For example, the measuring device 190 may be a smart meter belonging to a power company. The measuring device 190 may transmit an information element indicating the measurement result (integrated value of forward flow power or reverse flow power) in a first interval (e.g., 30 minutes) to the EMS 160 at each first interval. The measuring device 190 may transmit an information element indicating the measurement result in a second interval (e.g., 1 minute) that is shorter than the first interval to the EMS 160.

(Electricity storage device)
The power storage device according to the embodiment will be described below. As shown in Fig. 3, the power storage device 120 includes a BT 121, a monitoring unit 122, and a control unit 123. Although omitted in Fig. 3, the power storage device 120 may include a PCS.

BT121 is a storage cell that the storage device 120 has.

The monitoring unit 122 monitors the frequency of the power grid 12. For example, the monitoring unit 122 is connected to a measuring device installed between the power grid 12 and the facility 100, and monitors the frequency of the power measured by the measuring device. The measuring device may be installed in a similar position to the measuring device 190 described above.

The control unit 123 may include at least one processor. The at least one processor may be configured as a single integrated circuit (IC), or may be configured as multiple circuits (such as integrated circuits and/or discrete circuits) communicatively connected.

The control unit 123 controls the BT 121. In an embodiment, the control unit 123 executes specific control to autonomously control charging and discharging based on the frequency of the power grid 12.

(EMS)
The EMS according to the embodiment will be described below. As shown in Fig. 4, the EMS 160 includes a first communication unit 161, a second communication unit 162, and a control unit 163. In the embodiment, the EMS 160 is an example of a control device that controls the power storage device 120.

The first communication unit 161 is configured by a communication module. The communication module may be a wireless communication module that complies with standards such as IEEE802.11a/b/g/n/ac/ax, ZigBee, Wi-SUN, LTE, 5G, and 6G, or may be a wired communication module that complies with standards such as IEEE802.3.

For example, the first communication unit 161 communicates with the power management server 200 via the network 11. As described above, the first communication unit 161 communicates according to the first protocol. For example, the first communication unit 161 receives a first message from the power management server 200 according to the first protocol. The first communication unit 161 transmits a first message response to the power management server 200 according to the first protocol.

The second communication unit 162 is configured by a communication module. The communication module may be a wireless communication module that complies with standards such as IEEE802.11a/b/g/n/ac/ax, ZigBee, Wi-SUN, LTE, 5G, and 6G, or may be a wired communication module that complies with standards such as IEEE802.3.

For example, the second communication unit 162 communicates with devices included in the facility 100 (the solar cell device 110, the power storage device 120, and the fuel cell device 130). As described above, the second communication unit 162 communicates according to the second protocol. For example, the second communication unit 162 transmits a second message to the distributed power source according to the second protocol. The second communication unit 162 receives a second message response from the distributed power source according to the second protocol.

The control unit 163 may include at least one processor. The at least one processor may be configured as a single integrated circuit (IC), or may be configured as multiple circuits (such as integrated circuits and/or discrete circuits) communicatively connected.

For example, the control unit 163 may control the distributed power sources (solar cell device 110, power storage device 120, and fuel cell device 130) installed in the facility 100 based on control commands received from the power management server 200.

(Frequency fluctuation adjustment)
The following describes the adjustment of the fluctuation in frequency of the power system 12 according to the embodiment.

As shown in FIG. 5, the control related to frequency fluctuation adjustment differs depending on the fluctuation period of the adjustment target. Specifically, the control related to frequency fluctuation adjustment includes short-period control in which the fluctuation period of the adjustment target is a short period (e.g., tens of seconds to several minutes), medium-period control in which the fluctuation period of the adjustment target is a medium period longer than the short period (e.g., several minutes to several tens of minutes), and long-period control in which the fluctuation period of the adjustment target is a long period longer than the medium period (e.g., tens of minutes to several hours).

Here, short-cycle control may be referred to as GF (Governor Free). Short-cycle control is a control for eliminating supply and demand fluctuations that cannot be followed by medium-cycle control. For example, such supply and demand fluctuations may result in the suspension of operation of an adjustable power source that operates under short-cycle control.

Medium-term control may be called LFC (Load Frequency Control) or AFC (Automatic Frequency Control). Medium-term control is a control to eliminate supply and demand fluctuations that are difficult to predict.

Long-period control may be called DPC (Dispatching Power Control) or EDC (Economic Load Dispatching Control). Long-period control is a control for eliminating supply and demand fluctuations based on supply and demand forecasts.

Although not particularly limited, the specific control in which the energy storage device 120 autonomously controls charging and discharging based on the frequency of the power grid 12 may be applied to the short-period control (e.g., GF) described above.

For example, when specific control is executed in short-period control (e.g., GF), the operation shown in FIG. 6 may be executed. FIG. 6 illustrates a case in which AC and RA are separate entities. The regulated power of the power storage device 120 includes at least one of the discharge power of the power storage device 120 and the charge power of the power storage device 120. The regulated power of the power storage device 120 is power that is autonomously regulated by the power storage device 120 to keep the frequency of the power grid 12 constant.

As shown in FIG. 6, in step S10, the AC transmits a command (adjustment command) regarding adjustment of the frequency of the power grid 12 to the RA. The adjustment command may be a message conforming to the Open ADR described above.

In step S11, the RA transmits a control command for the storage device 120 to the EMS 160 for adjusting the frequency of the power grid 12. The control command may be a message conforming to a proprietary protocol between the RA and the EMS 160.

In step S20, EMS 160 sets properties related to the specific control in power storage device 120. The properties may include information elements for power storage device 120 to operate autonomously in the specific control. The properties may be considered as properties for setting the specific control in power storage device 120. Although not particularly limited, in ECHONET Lite (registered trademark), the setting of the properties may be executed by a SET command.

The energy storage device 120 performs specific control to autonomously control charging and discharging based on the frequency of the power grid 12 according to the property settings.

In step S21, the EMS 160 transmits a data request to the power storage device 120, requesting a combination of the frequency of the power grid 12 and the regulated power of the power storage device 120. Although not particularly limited, in ECHONET Lite (registered trademark), the data request may be executed by a GET command.

In step S22, the EMS 160 receives a data response from the power storage device 120, the data response including a combination of the frequency of the power grid 12 and the regulated power of the power storage device 120. Although not particularly limited, in ECHONET Lite (registered trademark), the data response may be performed by a GET response command.

Note that steps S21 and S22 are repeated according to the request period.

In step S30, EMS160 transmits performance information of the specific control to the RA. The performance information includes a combination of frequency and adjustment power for each request cycle. In the performance information, a timestamp is attached to the combination of frequency and adjustment power. The performance information may be a message according to a proprietary protocol between the RA and EMS160.

In step S31, the RA sends a report including performance information to the AC. The report may be a message conforming to the Open ADR described above.

Here, it is assumed that the period (request period) in which the EMS 160 requests data from the power storage device 120 is longer than the period (control period) in which the power storage device 120 executes specific control. For example, the request period may be 1 s. The control period may be 100 ms or less. The control period may be considered to be the period (monitoring period) in which the power storage device 120 monitors the frequency of the power grid 12.

On the other hand, when synchronizing the time using the time server 300, if there is a difference between the communication time to the time server 300 and the communication time back from the time server 300, it is expected that half of this difference will become an error. For example, if the communication time on the outbound journey is 0.01 seconds and the communication time on the back journey is 2.01 seconds, an error of 1 second will occur. Such an error can be corrected by periodic time synchronization, etc.

However, if we consider a case where time adjustment is performed using the time server 300 while specific control is being performed, the error (e.g., 1 second) may be corrected while specific control is being performed. In other words, the timestamps attached to the combination of frequency and adjustment power in the performance information from EMS 160 to RA may become discontinuous.

To solve this problem, the following operations are performed in the embodiment. The following options are possible:

(Option 1)
Option 1 will be described below with reference to Fig. 7. Option 1 describes a case where the EMS 160 assigns a time stamp. That is, the EMS 160 manages the time for assigning the time stamp, and uses the time managed by the time server 300 to perform time adjustment to correct the time managed by the EMS 160.

As shown in FIG. 7, in step S41, EMS160 receives a control command from RA.

In step S42, the EMS 160 performs time adjustment using the time server 300.

In step S43, EMS160 acquires the delay time and offset by adjusting the time before specific control. The delay time is the delay time (delay in FIG. 7) associated with acquiring the time managed by the time server 300. The delay time is the sum of the communication time on the way to the time server 300 and the communication time on the way back from the time server 300. The offset is the difference (offset in FIG. 7) between the time managed by the time server 300 and the time managed by EMS160.

In step S44, EMS160 stops the time adjustment function using the time server 300 before specific control.

In step S45, the power storage device 120 and the EMS 160 execute specific control. The specific control is the process of steps S20 to S22 shown in FIG. 6.

In step S46, after the specific control, the EMS 160 resumes the time adjustment function using the time server 300.

In step S47, EMS160 obtains the delay time and offset by adjusting the time after specific control.

In step S48, EMS160 determines whether the parameters related to time adjustment satisfy a specific condition. If the specific condition is satisfied, EMS160 executes the process of step S49. If the specific condition is not satisfied, EMS160 executes the process of step S50.

In option 1-1, the parameters may include a delay time before the specific control. The specific condition may include a condition that the delay time before the specific control is greater than a threshold. That is, in option 1-1, by determining whether the specific condition is satisfied, it is determined whether the time managed by EMS160 potentially contains an unacceptable error during the execution of the specific control.

Note that the offset before specific control is used to correct the time managed by EMS160 before specific control, so the magnitude of the offset does not matter.

In option 1-2, the parameters may include a delay time after the specific control. The specific condition may include a condition that the delay time after the specific control is smaller than a threshold value. That is, in option 1-2, by determining whether the specific condition is satisfied, it is determined whether the time managed by EMS160 potentially includes an unacceptable error after the specific control.

In options 1-3, the parameters may include an offset after the specific control. The specific condition may include a condition that the offset after the specific control is greater than a threshold. That is, in options 1-3, by determining whether the specific condition is satisfied, it is determined whether the time managed by EMS160 contained an unacceptable error during the execution of the specific control.

Two or more options selected from the above options 1-1 to 1-3 may be applied.

In step S49, EMS160 adjusts the timestamp attached to the result of the specific control (actual information) based on the offset after the specific control.

In other words, according to option 1-1 described above, if it is determined that the time managed by EMS160 potentially contains an unacceptable error during execution of specific control, the timestamp is adjusted based on the offset after the specific control.

According to option 1-2 described above, if it is determined that the time managed by EMS160 does not potentially contain an unacceptable error after specific control, the timestamp is adjusted based on the offset after specific control.

According to options 1-3 described above, if it is determined that the time managed by EMS160 contains an unacceptable error during execution of specific control, the timestamp is adjusted based on the offset after the specific control.

In step S50, EMS160 transmits the results of the specific control (actual information) with a time stamp to the RA.

(Option 2)
Option 2 will be described below with reference to Fig. 8. In option 2, a case will be described in which the power storage device 120 assigns a time stamp. That is, the power storage device 120 manages the time for assigning the time stamp, and uses the time managed by the time server 300 to perform time adjustment to correct the time managed by the power storage device 120.

As shown in FIG. 8, in step S61, EMS160 receives a control command from RA.

In step S62, the EMS 160 instructs the power storage device 120 to perform time adjustment using the time server 300.

In step S63, EMS160 acquires the delay time and offset from the power storage device 120 as a result of the power storage device 120 performing time adjustment before the specific control. The delay time is the delay time (delay in FIG. 8) associated with acquiring the time managed by the time server 300. The delay time is the sum of the communication time on the outbound path to the time server 300 and the communication time on the return path from the time server 300. The offset is the difference (offset in FIG. 8) between the time managed by the time server 300 and the time managed by the power storage device 120.

In step S64, the EMS 160 instructs the power storage device 120 to stop the time adjustment function using the time server 300 before specific control.

In step S65, the power storage device 120 and the EMS 160 execute specific control. The specific control is the process of steps S20 to S22 shown in FIG. 6.

In step S66, after the specific control, the EMS 160 instructs the power storage device 120 to resume the time adjustment function using the time server 300.

In step S67, EMS160 acquires the delay time and offset from the power storage device 120 as a result of the power storage device 120 performing time adjustment after the specific control.

In step S68, EMS160 determines whether the parameters related to time adjustment satisfy a specific condition. If the specific condition is satisfied, EMS160 executes the process of step S69. If the specific condition is not satisfied, EMS160 executes the process of step S70.

In option 2-1, the parameters may include a delay time before the specific control. The specific condition may include a condition that the delay time before the specific control is greater than a threshold. That is, in option 2-1, by determining whether the specific condition is satisfied, it is determined whether the time managed by the power storage device 120 potentially includes an unacceptable error during the execution of the specific control.

Note that the offset before specific control is used to correct the time managed by the power storage device 120 before specific control, so the magnitude of the offset does not matter.

In option 2-2, the parameters may include a delay time after the specific control. The specific condition may include a condition that the delay time after the specific control is smaller than a threshold value. That is, in option 2-2, by determining whether the specific condition is satisfied, it is determined whether the time managed by the power storage device 120 after the specific control potentially includes an unacceptable error.

In option 2-3, the parameters may include an offset after the specific control. The specific condition may include a condition in which the offset after the specific control is greater than a threshold value. That is, in option 2-3, by determining whether the specific condition is satisfied, it is determined whether the time managed by the power storage device 120 contained an unacceptable error during the execution of the specific control.

Two or more options selected from the above options 2-1 to 2-3 may be applied.

In step S69, EMS160 adjusts the timestamp attached to the result of the specific control (performance information) based on the offset after the specific control.

In other words, according to option 2-1 described above, if it is determined that the time managed by the energy storage device 120 potentially contains an unacceptable error while specific control is being performed, the timestamp is adjusted based on the offset after the specific control.

According to option 2-2 described above, if it is determined that the time managed by the energy storage device 120 does not potentially contain an unacceptable error after the specific control, the timestamp is adjusted based on the offset after the specific control.

According to option 2-3 described above, if it is determined that the time managed by the energy storage device 120 contains an unacceptable error during execution of the specific control, the timestamp is adjusted based on the offset after the specific control.

In step S70, EMS160 transmits the results of the specific control (performance information) with a time stamp to the RA.

(Action and Effects)
In the embodiment, in the case where the time stamp is added based on the time managed by the EMS 160, the EMS 160 stops the time adjustment function before the specific control and resumes the time adjustment function after the specific control (Option 1 described above). With this configuration, by using the time managed by the EMS 160 (local time) during the execution of the specific control, it is possible to prevent discontinuity in the time stamp.

In an embodiment, in a case where a time stamp is added based on the time managed by the power storage device 120, the EMS 160 instructs the power storage device 120 to stop the time adjustment function before the specific control, and instructs the power storage device 120 to resume the time adjustment function after the specific control (Option 2 described above). With this configuration, discontinuities in the time stamps can be prevented by using the time managed by the power storage device 120 (local time) while the specific control is being executed.

Under such a premise, when the time adjustment parameters satisfy the specific condition, the EMS160 adjusts the timestamp based on the offset after the specific control. With this configuration, when the error of the local time, such as the time managed by the EMS160 or the time managed by the power storage device 120, is assumed to be large during the execution of the specific control, the timestamp can be appropriately adjusted. In other words, when the error of the local time is assumed to be small during the execution of the specific control, unnecessary adjustment of the timestamp can be omitted (such as the above-mentioned options 1-1, 1-3, 2-1, and 2-3). Furthermore, when the local time is assumed to not include a potential error after the specific control, the timestamp can be appropriately adjusted. In other words, when the local time is assumed to include a potential error after the specific control, unnecessary adjustment of the timestamp can be omitted (such as the above-mentioned options 1-2 and 2-2).

[Other embodiments]
Although the present invention has been described by the above-mentioned embodiment, the description and drawings forming a part of this disclosure should not be understood as limiting the present invention. From this disclosure, various alternative embodiments, examples and operating techniques will become apparent to those skilled in the art.

Although not specifically mentioned in the above disclosure, a case may be assumed in which ECHONET Lite (registered trademark) is used as the protocol between the power storage device 120 and the EMS 160. In such a case, a command by which the EMS 160 instructs the power storage device 120 to perform time adjustment may be defined as a new SET command. A command by which the EMS 160 instructs the power storage device 120 to stop the time adjustment function may be defined as a new SET command. A command by which the EMS 160 instructs the power storage device 120 to resume the time adjustment function may be defined as a new SET command. A command by which the EMS 160 requests an offset from the power storage device 120 may be defined as a new GET command. A command by which the EMS 160 requests a delay time from the power storage device 120 may be defined as a new GET command.

Although not specifically mentioned in the above disclosure, stopping the time setting function may be interpreted as disabling or deactivating the time setting function, and resuming the time setting function may be interpreted as enabling or activating the time setting function.

In the above disclosure, a case has been exemplified in which the data response transmitted from the power storage device 120 to the EMS 160 includes the frequency of the power grid 12 itself. However, the above disclosure is not limited to this. The data response transmitted from the power storage device 120 to the EMS 160 may include frequency information related to the frequency of the power grid 12. For example, the frequency information may include a deviation in the frequency of the power grid 12 rather than the frequency of the power grid 12 itself. In such a case, in the above disclosure, "frequency" may be read as "frequency deviation."

Although not specifically mentioned in the above disclosure, the specific control may be executed in units of a predetermined time interval (e.g., 3 hours). If the time adjustment function is stopped while the specific control is being executed, the error that may occur in the predetermined time interval may be assumed to be about 10 to 100 ms.

In the above disclosure, an example is given of a case where the specific control is applied to short-period control (e.g., GF). However, the above disclosure is not limited to this. The specific control may be applied to control related to frequency fluctuation adjustment. In other words, the specific control may be applied to medium-period control (e.g., LFC or AFC) or long-period control (e.g., DPC or EDC).

The above disclosure has mainly described ECHONET Lite. However, the above disclosure is not limited thereto. The above disclosure is also applicable to other protocols such as SEP2.0 and KNX.

Although not specifically mentioned in the above disclosure, at least some of the functions of EMS160 may be executed by a server located on network 11. In other words, EMS160 may be provided by a cloud service.

1...Power management system, 11...Network, 12...Power system, 100...Facility, 110...Solar cell device, 120...Power storage device, 121...BT, 122...Monitoring unit, 123...Control unit, 130...Fuel cell device, 140...Load device, 160...EMS, 161...First communication unit, 162...Second communication unit, 163...Control unit, 190...Measuring device, 200...Power management server, 300...Time server

Claims (8)

a power storage device that executes specific control for controlling charging and discharging based on a frequency of a power grid;
A control device that controls the power storage device,
The control device includes:
before the specific control, stopping a time adjustment function for adjusting a time managed by the control device using a time managed by a time server;
restarting the time setting function after the specific control;
The power system adjusts a timestamp attached to a result of the specific control when a parameter related to the time adjustment satisfies a specific condition. The power system of claim 1, wherein the specific condition includes a condition in which a delay time associated with obtaining the time managed by the time server before the specific control is greater than a threshold value. The power system according to claim 1 or 2, wherein the specific condition includes a condition that the delay time associated with obtaining the time managed by the time server after the specific control is smaller than a threshold value. a power storage device that executes specific control for controlling charging and discharging based on a frequency of a power grid;
A control device that controls the power storage device,
The control device includes:
before the specific control, setting, in the power storage device, a stop of a time adjustment function relating to time adjustment that corrects a time managed by the control device using a time managed by a time server;
After the specific control, a restart of the time setting function is set in the power storage device;
The power storage device is
The power system adjusts a timestamp attached to a result of the specific control when a parameter related to the time adjustment satisfies a specific condition. The power system of claim 4, wherein the specific condition includes a condition in which a delay time associated with obtaining the time managed by the time server before the specific control is greater than a threshold value. The power system according to claim 4 or 5, wherein the specific condition includes a condition that the delay time associated with obtaining the time managed by the time server after the specific control is smaller than a threshold value. a control device that controls a power storage device that executes specific control for controlling charging and discharging based on a frequency of a power grid, stopping a time adjustment function related to time adjustment that corrects a time managed by the control device using a time managed by a time server, before the specific control;
the control device restarting the time setting function after the specific control;
The control method includes a step of adjusting a timestamp attached to a result of the specific control by the control device when a parameter related to the time adjustment satisfies a specific condition. a control device that controls a power storage device that executes specific control for controlling charging and discharging based on a frequency of a power grid, before the specific control, sets a time adjustment function for adjusting a time managed by the control device using a time managed by a time server to be stopped in the power storage device;
a step of the control device setting the power storage device to resume the time adjustment function after the specific control;
The control method includes a step of adjusting a timestamp attached to a result of the specific control by the power storage device when the parameter related to the time adjustment satisfies a specific condition.