JP2016039685A - Controller, power storage system comprising the same, and control method and control program for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to continuously use a load facility even at the time of long outage.SOLUTION: A controller 10 for a micro grid that is interconnected with a power system and comprises a DG, a storage battery system, and a load facility comprises: a distribution determination unit 11 that separates a switching unit for switching connection/disconnection between the power system and the micro grid when it is determined that voltage of the power system is lower than a threshold, and determines respective distributions of power to be supplied from the DG and the storage battery system to the load facility on the basis of a State Of Charge of the storage battery system; and a control unit 12 for controlling, on the basis of the power distributions determined by the distribution determination unit 11, the respective DG and storage battery system so as to supply power to the load facility.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a control device, a power storage system including the control device, a control method thereof, and a control program.

Conventionally, in a power supply system including a distributed power source and a storage battery system, a technique for adjusting the output of the distributed power source or the storage battery system according to the charging rate of the storage battery system has been proposed.
For example, in Patent Document 1 below, when the load suddenly changes, voltage fluctuations and frequency fluctuations of the power supply system are monitored, reactive power from the power storage equipment is adjusted so as to suppress such fluctuations, and active power of the power storage equipment is adjusted. Describes a power supply system adjustment device that compensates for unbalance.
In the following Patent Document 2, a first distributed power source that does not have an automatic frequency control function connected to an independent power system, a second distributed power source that charges and discharges a storage battery and has an automatic frequency control function, A power supply system is described in which the target frequency of the independent power supply system is set in accordance with the charging rate of the storage battery in the distributed power source 2 to control the output suppression and the output suppression stop of the first distributed power source.

JP 2012-130146 A Japanese Patent No. 4369450

By the way, for example, in a relatively small microgrid equipped with a distributed power supply and a storage battery system, when the power system uses a load facility even during a power failure, it takes time to start up the distributed power supply. A storage battery system for supplying power to the load facility was required until the power source was started. In that case, since the storage battery system is discharged by the load equipment, the charge rate of the storage battery system decreases in a short time, and it becomes easy to reach the end-of-discharge state, or it can cope with a long-time power failure. There was a problem that a large capacity storage battery system was required.
However, Patent Document 1 describes control of power storage equipment when the load suddenly changes, and Patent Document 2 describes the charge rate of the storage battery when it is connected to an independent power system and is generated by a distributed power source. Although the output suppression of the first distributed power supply according to is described, when using load equipment at the time of a power failure, it is described that the storage battery system is supported for as long as possible and the use of the load equipment is continued. Absent.

  The present invention has been made in view of such circumstances, and a control device that can continue to use load equipment even during a long-time power outage, a power storage system including the control device, a control method thereof, and a control program The purpose is to provide.

In order to solve the above problems, the present invention employs the following means.
The present invention is a control device for a partial power system that is linked to a power system and includes a power generation device, a power storage device, and a load facility, and when it is determined that the voltage of the power system is smaller than a predetermined threshold value, Switching means for switching connection / disconnection between the power system and the partial power system is disconnected, and each power distribution supplied from the power generation device and the power storage device to the load facility is based on a charging rate of the power storage device Distribution determining means for determining power, and control means for controlling each of the power generation device and the power storage device according to the power distribution determined by the distribution determination means and supplying power to the load facility, and Provided is a control device that prevents the device from being fully charged or the power storage device from being discharged.

  According to the present invention, in a partial power system that is linked to a power system and includes a power generation device, a power storage device, and a load facility, when it is determined that the voltage of the power system is smaller than a predetermined threshold, The connection with the power system is disconnected, and based on the charging rate of the power storage device, each power distribution between the power generation device and the power storage device supplied to the load facility is determined, and the power generation device and the power storage device are determined by the determined power distribution. Is controlled to supply power to the load facility. The voltage of the power system becomes smaller than a predetermined threshold when a low voltage event including a power system power failure occurs.

  As described above, since the power distribution between the power generation device and the power storage device is determined by the charging rate of the power storage device, when the charge rate of the power storage device is large, the power storage device is made larger by increasing the power distribution of the power storage device than the power generation device. It can prevent full charge state, and when the charge rate of the power storage device is small, it can prevent the power storage device from being in a discharge end state by making the power distribution of the power storage device smaller than the power generation device Can do. Thereby, since the power storage device can be used continuously, even when a low voltage event such as a power failure continues for a long time, the load facility can be used continuously, and the battery utilization rate of the power storage device can be improved. This leads to a reduction in fuel consumption of the power generation device.

  The control means of the control device is based on a difference between a target charge rate that is a target for keeping the charge rate of the power storage device within a predetermined range and a current value charge rate that is a current charge rate of the power storage device. It is good also as controlling charging / discharging of the said electrical storage apparatus.

  Accordingly, when the current value charging rate exceeds the target charging rate, by controlling the current charging rate to be within a predetermined range, for example, if the predetermined range is changed from a fully charged state to a discharge end state, the power storage device Can be controlled so as to prevent overcharging that charges beyond the fully charged state, or overdischarge that discharges beyond the end-of-discharge state, and the power storage device can be used safely.

The distribution determination means of the control device may determine the power distribution based on rated outputs of the power generation device and the power storage device.
Thereby, electric power distribution can be determined simply.

  The control means of the control device changes the output of the power generation device at a predetermined rate based on the output calculation value of the power generation device of the power distribution determined by the distribution determination means, and the output of the power generation device is You may control so that it may become substantially constant.

  In this way, the output of the power generation device is changed at a predetermined rate, and the power storage device compensates for excess or deficient power, so that the output of the power generation device is controlled to be substantially constant, resulting in frequent output response changes. Excessive fuel consumption is suppressed.

  The distribution determination means of the control device determines the power distribution to be shared by the power generation device based on an average value of the total load of the load facility at a predetermined time interval, and shares the power generation device from the total load. The power distribution to be shared by the power storage device by subtracting the power distribution may be determined.

  Thus, by determining the output of the power generation device based on the average value of the total load, the output shared by the power generation device can be suppressed with respect to the load that changes every moment. Can be used for a long time by the power generation device and the power storage device.

In the control device, the partial power system includes a voltage measurement unit that measures and outputs a voltage value of the load facility between the power storage device and the load facility, and the voltage measurement unit measures the voltage value. The reactive power adjustment amount may be determined based on the difference between the voltage of the load facility and a predetermined target voltage, and the reactive power of the adjustment amount may be controlled by the power storage device.
By adjusting the reactive power, it is possible to easily control the voltage of the load facility.

  The voltage measuring means of the control device outputs the measured voltage value of the load facility to the power storage device, and the power storage device controls the reactive power of the adjustment amount based on the acquired voltage value of the load facility. May be.

  Thereby, compared with the case where the information on the voltage value of the load equipment is once transmitted to the control means and the power storage device acquires a command from the control means and adjusts the reactive power, the control delay (for example, the voltage measurement means and the control is controlled). The time required for communication with the means can be shortened, and reactive power can be controlled promptly. The present invention is preferably used when responsiveness is required.

  The present invention is a control device for a power storage system that is connected to a power system, a power generation device and a power storage device are provided in a container, and supplies power to a load facility, and the voltage of the power system is smaller than a predetermined threshold value. And switching means for switching connection / disconnection between the power system and the power generation device and the power storage device in the container when determined, and based on the charging rate of the power storage device, the power generation device and the power storage Distribution determining means for determining each power distribution to be supplied from the apparatus to the load facility, and controlling the power generation device and the power storage device by the power distribution determined by the distribution determination means, respectively, to the load facility There is provided a control device that includes control means for supplying electric power, and prevents the power storage device from being fully charged or the power storage device from being discharged.

  According to the present invention, in the power storage system that is connected to the power system, the power generation device and the power storage device are provided in the container, and supplies power to the load facility, the voltage of the power system is determined to be smaller than the predetermined threshold value. In addition, the connection between the power system and the power generation device and the power storage device in the container is disconnected, and based on the charging rate of the power storage device, each power distribution to be supplied from the power generation device and the power storage device to the load facility is determined and determined. The power generation apparatus and the power storage apparatus are controlled by the distributed power, and power is supplied to the load facility. The voltage of the power system becomes smaller than a predetermined threshold when a low voltage event including a power system power failure occurs.

As described above, since the power distribution between the power generation device and the power storage device is determined by the charging rate of the power storage device, when the charge rate of the power storage device is large, the power storage device is made larger by increasing the power distribution of the power storage device than the power generation device. It can prevent full charge state, and when the charge rate of the power storage device is small, it can prevent the power storage device from being in a discharge end state by making the power distribution of the power storage device smaller than the power generation device Can do.
As a result, even if a low voltage event such as a power failure continues for a long period of time, the power storage system of the present invention can continue to use the load facility for a longer period of time, improve the battery utilization rate of the power storage device, It leads to consumption reduction.

The present invention includes a power generation device and a power storage device linked to a power system, and the control device according to any one of the above, and a power storage system in which the power generation device, the power storage device, and the control device are incorporated in a container. I will provide a.
According to the present invention, even when the power system becomes unstable by configuring the power storage system by incorporating the control device, the power generation device, and the power storage device into the container, and transporting and installing the container together, the power storage system The power supply can be extended for a long period of time, and long-term power supply by combining the power generation device and the power storage device can be performed, which can be used as a power source capable of responding to stable power over a long period of time.

  The present invention is a control method for a partial power system that is linked to a power system and includes a power generation device, a power storage device, and load equipment, and when it is determined that the voltage of the power system is smaller than a predetermined threshold value, Distributing determination process in which connection between the power system and the partial power system is disconnected, and each power distribution to be supplied from the power generation device and the power storage device to the load facility is determined based on a charging rate of the power storage device And a control process for controlling each of the power generation device and the power storage device according to the power distribution determined by the distribution determination process and supplying power to the load facility, and the power storage device is in a fully charged state, Alternatively, a control method for preventing the power storage device from entering a discharge end state is provided.

  The present invention is a control program for a partial power system that is linked to a power system and includes a power generation device, a power storage device, and a load facility, and when the voltage of the power system is determined to be smaller than a predetermined threshold, Distribution determination processing for determining the respective power distributions to be supplied from the power generation device and the power storage device to the load facility based on the charging rate of the power storage device, with the connection between the power system and the partial power system being disconnected. And controlling the power generation device and the power storage device according to the power distribution determined by the distribution determination processing and causing the computer to execute control processing for supplying power to the load facility, so that the power storage device is fully charged. A control program for preventing the state or the power storage device from entering a discharge end state is provided.

  The present invention has an effect that it is possible to continue using the load facility even during a long-time power outage.

1 is a schematic configuration diagram of a microgrid to which a control device according to the present invention is applied. It is a functional block diagram of a control device concerning the present invention. It is a figure for demonstrating an example of the load fluctuation suppression control which considered the charging rate of the secondary battery which concerns on this invention. It is a schematic structure of the container to which the control apparatus which concerns on the modification of this invention is applied.

  Hereinafter, embodiments of a control device, a power storage system including the control device, a control method thereof, and a control program according to the present invention will be described with reference to the drawings.

FIG. 1 shows a schematic configuration of a microgrid 1 (partial power system) including an EMS (Energy Management System) (control device) 10 according to the present embodiment.
As shown in FIG. 1, a microgrid 1 according to this embodiment is connected to and connected to a power system 2 through a connecting line 7, and a storage battery system (power storage device) 3 and a diesel engine power generation as a distributed power source. Machine (hereinafter referred to as “DG”) (power generation device) 4, load facility 6, first switching unit (switching means) 5a, second switching unit 5b, third switching unit 5c, and fourth switching unit 5d. And. In addition, voltage measuring units (voltage measuring means) Pa and Pb are connected to output voltage values measured at the respective connection locations. In the present embodiment, an example is shown in which one power storage device and one distributed power source are provided to simplify the drawing, but the present invention is not limited to this, and there are a plurality of power storage devices and distributed power sources. It may be provided.

The load facility 6 is a facility that consumes electric power, such as a motor or an electric lamp, and can be connected to the storage battery system 3 and the DG 4 and is supplied with power from a connection destination. Although FIG. 1 shows an example in which three load facilities are provided, the number of load facilities provided in the microgrid 1 is not particularly limited.
The first switching unit 5 a is provided on the connecting line 7 and switches connection / disconnection between the power system 2 and the microgrid 1. When it is determined that the voltage of the power system 2 is smaller than the predetermined threshold, the first switching unit 5a determines that the power system 2 is in an abnormal state such as a power failure, and the power system 2 and the microgrid 1 are not connected. To be.

The second switching unit 5b is, for example, a high-speed switch such as a thyristor, and one end is connected to a junction of a path connected from the load facility 6 and the storage battery system 3, and the other end is connected to the first switching unit 5a. The connection / disconnection between the storage battery system 3 and the power system 2 or the connection / disconnection between the storage battery system 3 and the DG 4 is switched.
One end of the third switching unit 5c is connected between the first switching unit 5a and the second switching unit 5b, the other end is connected to the DG 4, and the connection / disconnection between the DG 4 and its upstream side is switched.
The fourth switching unit 5d has one end connected to the storage battery system 3 and the other end connected to the junction of the path connecting the load facility 6 and the power system 2, and the storage battery system 3 and the load 6, or the storage battery system 3 and the upstream side. (For example, connection / disconnection with the power system 2, DG4) is switched.

The storage battery system 3 includes a secondary battery (storage battery) 3a and a PCS (Power Conditioning System) 3b.
The secondary battery 3a is not particularly limited, such as a lithium ion secondary battery, a lead secondary battery, or a nickel hydride secondary battery, but is preferably a lithium ion secondary battery because of good charge / discharge followability.
The PCS 3b controls the bidirectional inverter 3c based on the charge / discharge command value acquired from the EMS 10, and adjusts the charging rate SOC (State of Charge) of the secondary battery 3a.

  The bidirectional inverter 3c is an AC / DC converter that converts AC to DC and DC to AC. For example, the bidirectional inverter 3c is controlled by the PCS 3b and stored in the secondary battery 3a to obtain a desired charge / discharge command value. The direct current power is converted into alternating current power and discharged from the secondary battery 3a. Further, the bidirectional inverter 3c is controlled by the PCS 3b, converts the AC power acquired from the DG 4 and the power system 2 to DC power to obtain a desired charge / discharge command value, and converts the converted power to the secondary battery 3a. To output and charge the secondary battery 3a.

  The storage battery system 3 can be operated in the operation mode of the grid connection mode and the independent operation mode. In the grid connection mode, when the storage battery system 3 is connected to the power system 2 or DG4 or the like, current control is performed, and the AC voltage, frequency, and phase difference obtained from the upstream side (for example, the power system 2 and DG4) are It is an operation mode controlled so that there is no. The self-sustained operation mode is an operation mode in which the storage battery system 3 is disconnected from the power system 2 and the DC power stored in the secondary battery 3a is converted into AC power having a predetermined frequency and supplied to the load facility 6.

The voltage measurement unit Pa sends information about the voltage value of the power system 2 measured between the junction of the path connected from the second switching unit 5b and the third switching unit 5c and the first switching unit 5a to the DG 4 and the EMS 10. Output is enabled.
The voltage measuring unit Pb is connected between the second switching unit 5b and the fourth switching unit 5d and between the load facility 6 and measures the voltage value of the load facility 6 between the storage battery system 3 and the load facility 6. Then, the information on the measured voltage value can be output to the storage battery system 3 and the EMS 10, and the total load of the load facility 6 is measured.
The voltage measurement units Pa and Pb may be set as appropriate in the route near the measurement unit as long as voltage information similar to the measurement point is obtained, and the measurement position is not strictly limited.

  In the present embodiment, the voltage measurement units Pa and Pb will be described as outputting information of the measured voltage values to the EMS 10, but the present invention is not limited to this. For example, when responsiveness is required, the voltage measurement units Pa and Pb Information on the voltage value measured by the measurement unit Pa may be output to the DG 4, and information on the voltage value measured by the voltage measurement unit Pb may be output to the storage battery system 3. For example, when the storage battery system 3 controls the reactive power of the adjustment amount based on the voltage value of the load facility 6, the storage battery system 3 acquires the voltage value information directly from the voltage measurement unit Pb without going through the EMS 10. By controlling the reactive power, the time required to exchange information with the EMS 10 can be shortened, so that the reactive power can be quickly controlled.

  DG4 is an example of a distributed power source. The distributed power source is not limited to a diesel engine generator, and may be a generator that uses natural energy such as solar power generation or wind power generation in addition to a generator that uses fuel such as a gas engine or a gas turbine. Good.

The EMS 10 includes, for example, a CPU (Central Processing Unit) (not shown), a RAM (Random Access Memory), a computer-readable recording medium, and the like. A series of processing steps for realizing various functions to be described later are recorded in a recording medium or the like in the form of a program, and the CPU reads the program into a RAM or the like to execute information processing / arithmetic processing. Thus, various functions described later are realized.
Specifically, as illustrated in FIG. 2, the EMS 10 includes a distribution determination unit (distribution determination unit) 11 and a control unit (control unit) 12.

The EMS 10 controls, for example, switching between connection and non-connection of the first switching unit 5a, the second switching unit 5b, the third switching unit 5c, and the fourth switching unit 5d, performs start-up control of the DG 4, The facility 6 and the power generation state are monitored. For example, when the EMS 10 determines that the voltage of the power system 2 is smaller than a predetermined threshold, the EMS 10 outputs a command to disconnect the first switching unit 5 a that switches connection / disconnection between the power system 2 and the microgrid 1. Note that the voltage of the electric power system 2 becomes smaller than the predetermined threshold value when an abnormal low voltage event such as a power failure occurs, and the predetermined threshold value is, for example, minus 20% of the reference voltage of the electric power system 2. .
The EMS 10 prevents the secondary battery 3a of the storage battery system 3 from being fully charged or the secondary battery 3a of the storage battery system 3 from being discharged.

The distribution determination unit 11 distributes each power distribution supplied from the DG 4 and the storage battery system 3 to the load facility 6 based on the charging rate of the secondary battery 3a of the storage battery system 3 (hereinafter also referred to as “SOC”: State Of Charge). decide.
For example, the distribution determination unit 11 determines power distribution based on the rated outputs of the DG 4 and the storage battery system 3. Specifically, the output of DG4 is determined from the rated output ratio as shown in the following formula (1), and the output of the storage battery system 3 is subtracted from the total load as shown in the formula (2). calculate. Α in the equation (1) is a value determined based on the current SOC, and the distribution of the distributed power output is adjusted by adding α to the calculation of the distribution of the distributed power output. . Details of α will be described later.

Here, in this embodiment, the distributed power output and the distributed power rated output are the output of DG4 and the rated output of DG4.
Distributed power output = [(Load × Distributed power supply rated output) / (Distributed power supply rated output + Storage battery system rated output)] + α (1)
Battery system output = total load-distributed power output (2)

Further, the control unit 12 is based on a difference between a target SOC that is a target for keeping the charging rate of the secondary battery 3a of the storage battery system 3 within a predetermined range and a current value SOC that is an SOC of the current secondary battery 3a. The charging / discharging of the secondary battery 3a is controlled. Specifically, the parameter α included in the above equation (1) is expressed by the following equation (3). In the present embodiment, the predetermined range is changed from a predetermined full charge state to a predetermined discharge end state, for example, the predetermined full charge state is 90% and the predetermined discharge end state is 10%. K is a constant.
α = −K (current value SOC−target SOC) (3)

Here, in determining the parameter α, an arithmetic expression is given in consideration of whether the charging tendency is controlled or the discharging tendency is controlled according to the value of the current value SOC.
Specifically, when the SOC is 50% or more, the following equation (4) is used. If the current value SOC is 90% or more, the parameter α becomes negative (−), and the secondary battery 3a tends to discharge. The parameter is controlled by Thereby, it can prevent that the charging rate of the secondary battery 3a of the storage battery system 3 reaches | attains a predetermined full charge state.
α = −K (current value SOC−90%) <0 (4)

When the SOC is less than 50%, the following equation (5) is used. If the current value SOC is 10% or less, the parameter α is positive (+), and the secondary battery 3a is controlled to be charged. Parameter α.
By adding the parameter α thus obtained to the above equation (1), the charge rate of the secondary battery 3a of the storage battery system 3 can be prevented from reaching a predetermined discharge end state, and the power of the DG 4 Can be used to charge the secondary battery 3a.
α = −K (current value SOC−10%)> 0 (5)

  Thereby, when the current value exceeds the target SOC, the battery is charged beyond the fully charged state of the storage battery system 3 by controlling it so as to fall within a predetermined range (for example, 10% to 90%). Control can be performed to prevent overcharge or overdischarge that is discharged beyond the end-of-discharge state, and the storage battery system 3 can be used safely.

  In the present embodiment, when determining the parameter α, the case where the SOC is 50% or more and the case where it is less than 50% is divided, but the method for determining the parameter α is not limited to this. For example, a range from a charging lower limit value (for example, SOC 20%) that is a higher charging rate than a predetermined discharge end state to a charging upper limit value (for example, SOC 70%) that is a lower charging rate than a predetermined full charging state is allowed. The parameter α may be calculated using the above equation (4) when the SOC is greater than 70%, and using the above equation (5) when the SOC is less than 20%. .

Thus, by using the above formulas (1) to (5), the distribution determination unit 11 can determine the distributed power output (output of DG4) and the storage battery system 3 based on the current SOC of the secondary battery 3a. The output of is calculated.
The control unit 12 controls the DG 4 and the storage battery system 3 according to the power distribution determined by the distribution determination unit 11 and supplies power to the load facility 6.

The control unit 12 changes the output of the DG 4 at a predetermined rate based on the output calculation value of the DG 4 of the power distribution determined by the distribution determination unit 11 (for example, in steps of 10 to 20% of the rated output of the DG 4). It is preferable to control the output of the DG 4 to be substantially constant.
In this way, excess or deficient electric power is compensated for by the storage battery system 3 and frequent output response changes of the DG 4 are not performed, so that excessive fuel consumption that easily occurs when the DG 4 output changes can be suppressed.

In addition, after starting up DG4 (distributed power supply), output fluctuation control that suppresses frequency fluctuation is performed in the storage battery system 3 by absorption control for load fluctuation by the storage battery system 3, but when voltage fluctuation suppression control is performed. The reactive power may be controlled. Specifically, as shown in the following control expression (6), the EMS 10 detects the voltage of the load facility 6 measured by the voltage measuring unit Pb and a predetermined target voltage (for example, the rated voltage is a target voltage). The reactive power adjustment amount is determined on the basis of the difference between the two and the storage battery system 3 to control the reactive power of the adjustment amount. T is a constant.
Reactive power = -T (Current voltage-Target voltage) (6)

Here, when the sign of the calculated value is minus (−), the reactive power is controlled on the charging side, and when it is plus (+), the reactive power is controlled on the discharging side.
When reactive power is controlled, information on the voltage measured by the voltage measuring unit Pb is output to the EMS 10, the storage battery system 3 is controlled based on a command from the EMS 10, and reactive power is supplied from the storage battery system 3 by voltage fluctuation. However, when responsiveness is required, information on the voltage measured by the voltage measuring unit Pb may be directly output to the storage battery system 3. Similarly, when responsiveness is required for the output (active power) control of the storage battery system 3, the total output of the load facility 6 may be measured and controlled by the voltage measuring unit Pb.

Below, the effect | action of EMS10 concerning this embodiment and the microgrid 1 provided with the same is demonstrated.
When a low voltage event such as a power failure occurs and it is determined that the voltage of the power system 2 measured by the voltage measuring unit Pa is smaller than a predetermined threshold, the second switching unit 5b is brought into a disconnected state. Thereafter, the storage battery system 3 is operated in the self-sustaining operation mode, and power supply from the storage battery system 3 to the load facility 6 is started. In the self-sustained operation mode, the power supply to the load facility 6 is a period using only the secondary battery 3a, and the active power and the invalid output are supplied from the secondary battery 3a.
Subsequently, when a start command is issued to the DG 4 and it is detected that power can be supplied from the DG 4 after the time necessary for starting the DG 4 has elapsed (start of the DG 4 is completed), the first The switching unit 5a is set in a disconnected state, and then the third switching unit 5c is set in a connected state.

  The second switching unit 5b is brought into a connected state, and power supply from the DG 4 to the load facility 6 side is started. At this time, the storage battery system 3 assumes that the power system 2 has recovered from the voltage abnormality by detecting the voltage Pa, and starts operation in the grid interconnection mode. Switching from the self-sustained operation mode of the storage battery system 3 to the grid connection mode is performed by switching the PCS control by the PCS 3b of the storage battery system 3 instantaneously from the voltage control to the grid connection mode. Since switching to (current control), switching without interruption is performed.

  The voltage is measured in the voltage measuring unit Pb, the total load of the load facility 6 is calculated, and the distribution of the supplied power between the storage battery system 3 and the DG 4 is calculated. The power supply of the storage battery system 3 and the DG 4 is controlled so that the respective distributions are determined, and charging / discharging of the secondary battery 3a is performed based on the current value SOC of the secondary battery 3a provided in the storage battery system 3. Be controlled.

  As described above, according to the EMS 10 (control device) according to the present embodiment, the microgrid 1 including the control device, the control method thereof, and the control program, the power grid 2 and the DG 4, the storage battery system 3, and the load When a low voltage event such as a power failure occurs in the microgrid 1 having the facility 6 and the voltage of the power system 2 is determined to be smaller than a predetermined threshold, the connection between the power system 2 and the microgrid 1 is disconnected. Then, based on the current value SOC of the secondary battery 3a of the storage battery system 3, the power distribution between the DG 4 and the storage battery system 3 to be supplied to the load facility 6 is determined, and the DG 4 and the storage battery system 3 are determined by the determined power distribution. Are controlled, and power is supplied to the load facility 6.

  As described above, since the power distribution between the DG 4 and the storage battery system 3 is determined by the SOC of the secondary battery 3a, when the current value SOC of the secondary battery 3a is larger than the determination criterion (for example, 50%), the storage battery from DG4. By increasing the power distribution of the system 3, the secondary battery 3a of the storage battery system 3 can be prevented from being fully charged, and the current value SOC of the secondary battery 3a is determined as a criterion (for example, 50%). In the case of being smaller, it is possible to prevent the secondary battery 3a from being in an end-of-discharge state by increasing the power distribution of the DG 4 and reducing the power distribution of the storage battery system 3. Thereby, even if a low voltage event such as a power failure continues for a long time, the load facility can be used continuously, the battery utilization rate of the storage battery system 3 is improved, and the fuel consumption of the DG 4 is reduced.

FIG. 3 is a diagram illustrating an example in which the EMS 10 according to the present embodiment performs suppression control when a load fluctuation of the load facility 6 occurs. The power distribution shown here is an example, and control of power distribution is not limited to this.
The solid line indicates the state of load fluctuation, the upper part of the dotted line indicates the power supplied by the storage battery system 3, and the lower part of the dotted line indicates the power supplied by DG4.

  Since the load during the period from time t1 to time t2 is small, the secondary battery 3a of the storage battery system 3 is charged with the power supplied from the DG4. After time t2, the load is relatively large, and the DG 4 and the storage battery system 3 are operated with the power distribution (for example, DG4: storage battery system 3 = 1: 1 in FIG. 3) obtained as a result of the calculation. When the load is reduced and the SOC of the secondary battery 3a is sufficient and the secondary battery 3a is controlled to the discharge side, at time t3, DG4 is reduced by about 20% in a stepped manner to supply power to the load facility 6. The remaining power is supplied from the storage battery system 3. Thereafter, the power distribution between the DG 4 and the storage battery system 3 is determined in accordance with the SOC of the current secondary battery 3a. Further, as shown in FIG. 3, the DG 4 is operated at a constant output as much as possible, so that excessive fuel consumption can be suppressed.

Further, when the abnormality of the power system 2 is restored and the voltage of the power system 2 becomes larger than a predetermined threshold, the DG 4 moves to a stop operation.
When it is determined that the voltage of the power system 2 measured by the voltage measuring unit Pa is greater than a predetermined threshold value and is maintained for a predetermined time or longer, the second switching unit 5b is brought into a disconnected state. Thereafter, the storage battery system 3 is operated in the self-sustaining operation mode, a stop command is issued to the DG 4, the first switching unit 5 a is disconnected, and then the third switching unit 5 c is disconnected.
Then, the 1st switching part 5a is made into a connection state, the 2nd switching part 5b is made into a connection state, and electric power supply is started by the load equipment 6 side of the electric power grid | system 2. FIG.

At this time, the storage battery system 3 confirms that the power system 2 has recovered from the voltage abnormality by detecting the voltage of Pa, and starts operation in the grid connection mode. Switching from the self-sustained operation mode of the storage battery system 3 to the grid connection mode is performed by switching the PCS control by the PCS 3b of the storage battery system 3 instantaneously from the voltage control to the grid connection mode. Since switching to (current control), switching without interruption is performed.
Thereafter, the storage battery system 3 can perform stable power supply even when a load fluctuation of the load facility 6 occurs in the grid connection mode.

  To respond to long-term power outages in customers who need uninterruptible power in order to continue to use loads such as in microgrids and large-scale semiconductor factories, conventionally, installation of large-scale emergency diesel engine generators and large-capacity storage The installation of the system and the installation of a simple emergency diesel engine generator combined with a small-capacity energy storage system have made it possible to continue using the load. Large diesel engine generators require expensive equipment and fuel costs, and a storage battery system is required to cover the power supply until the diesel engine generator is started. In addition, in the event of a long power outage, there is a limit to how long the storage battery capacity can be increased with the storage battery system alone, so that an independent power source that can combine a diesel engine generator and a storage battery system can be configured during a long power outage. A large-scale standby power supply is required, which is very expensive as an emergency system.

  Furthermore, in the past, the capacity of the DG was output in excess of the load, and the shortage of capacity due to the load response delay of the large DG was supplied by a small-capacity storage battery system. There is a problem that both operating costs become large. On the other hand, according to the present embodiment, a relatively small DG and a fuel consumption of DG are reduced, and a storage battery system with a medium capacity to a small capacity is introduced to maximize the utilization rate of the storage battery system. By optimizing the distribution control of the storage battery system and DG, both the initial investment cost and the operating cost can be suppressed.

[Modification 1]
In addition, in this embodiment, although the distribution determination part 11 determined electric power distribution based on the rated output of a distributed power supply (DG4) and the rated output of the storage battery system 3, it is not limited to this. For example, the distribution determination unit 11 determines the power distribution to be shared by the DG 4 based on the average value of the total load of the load facility 6 at a predetermined time interval (for example, every 10 minutes), and the power to be shared from the total load to the DG 4 It is also possible to determine the power distribution to be shared by the storage battery system 3 by subtracting the distribution. Specifically, power distribution between the DG 4 and the storage battery system 3 is determined by the following equations (7) and (8). Note that α in equation (7) is obtained in the same manner as α described in equations (3) to (5) above.

Distributed power output = (Average value of total load output at predetermined time intervals) + α (7)
Battery system output = total load-distributed power output (8)
Thus, by determining the output of DG4 based on the average value of the total load, the output shared by DG4 is suppressed so as to be suitable for the load output change of load equipment 6 that changes every moment and the SOC of storage battery system 3. Therefore, the fuel consumption is suppressed, the utilization rate of the storage battery system 3 is more effectively used, and the distributed power source and the storage battery system 3 can be operated for a longer period of time.

[Modification 2]
Moreover, EMS10 which concerns on this embodiment is not limited to the microgrid 1, For example, you may apply to the electrical storage system (Energy Storage System: ESS) 20.
Specifically, as shown in FIG. 4, DG4 (distributed power supply), storage battery system 3, and EMS 10 may be incorporated in the ESS container 21 and used as a power supply that can be used for a long time. Note that the calculation of the power distribution of the DG 4 and the storage battery system 3, the point of adjusting the power distribution according to the SOC of the secondary battery 3a, and the control of the switching units 5a to 5d are the same as in the above embodiment. Details are omitted.
In this way, by incorporating the EMS 10 according to the present invention into the ESS, transporting the ESS container 21 together, and installing it, the storage battery system 3 and the DG 4 can be combined to supply power for a longer time. By transporting and installing in an unstable area at an early stage, it can be used as a power source that can handle stable power over a long period of time.

1 Microgrid 2 Power system 3 Storage battery system 4 Diesel engine generator (DG)
5a 1st switching part 6 Load equipment 10 Energy management system (EMS)
11 Allocation determination unit (allocation determination means)
12 Control unit (control means)
20 Power Storage System 21 ESS Container Pb Voltage Measurement Unit

Claims (11)

A control device for a partial power system that is linked to a power system and includes a power generation device, a power storage device, and a load facility,
When it is determined that the voltage of the power system is smaller than a predetermined threshold,
Switching means for switching connection / disconnection between the power system and the partial power system is disconnected,
Distribution determining means for determining each power distribution to be supplied from the power generation device and the power storage device to the load facility based on a charging rate of the power storage device;
Control means for controlling each of the power generation device and the power storage device according to the power distribution determined by the distribution determination means, and supplying power to the load facility,
A control device for preventing the power storage device from being fully charged or the power storage device from being discharged.   The control unit is configured to control the power storage device based on a difference between a target charge rate that targets the charge rate of the power storage device within a predetermined range and a current value charge rate that is a current charge rate of the power storage device. The control apparatus of Claim 1 which controls charging / discharging.   The control device according to claim 1, wherein the distribution determination unit determines the power distribution based on rated outputs of the power generation device and the power storage device.   The control means changes the output of the power generation apparatus at a predetermined rate based on the output calculation value of the power generation apparatus of the power distribution determined by the distribution determination means, and the output of the power generation apparatus becomes substantially constant. The control device according to claim 3, which performs control as described above.   The distribution determining means determines the power distribution to be shared by the power generation device based on an average value of the total load of the load facility at a predetermined time interval, and the power distribution to be shared from the total load to the power generation device. The control device according to claim 1 or 2, wherein a power distribution to be subtracted and shared by the power storage device is determined. The partial power system includes a voltage measuring unit that measures and outputs a voltage value of the load facility between the power storage device and the load facility,
The reactive power adjustment amount is determined based on a difference between the voltage of the load facility measured by the voltage measuring means and a predetermined target voltage, and the reactive power of the adjustment amount is controlled by the power storage device. The control device according to claim 5. The voltage measuring means outputs the measured voltage value of the load facility to the power storage device,
The control device according to claim 6, wherein the power storage device controls the reactive power of the adjustment amount based on the acquired voltage value of the load facility. A control device of a power storage system that is connected to a power system, a power generation device and a power storage device are provided in a container, and supplies power to a load facility,
When it is determined that the voltage of the power system is smaller than a predetermined threshold,
Switching means for switching connection / disconnection between the power system and the power generation device and the power storage device in the container is disconnected,
Distribution determining means for determining each power distribution to be supplied from the power generation device and the power storage device to the load facility based on a charging rate of the power storage device;
Control means for controlling each of the power generation device and the power storage device according to the power distribution determined by the distribution determination means, and supplying power to the load facility,
A control device for preventing the power storage device from being fully charged or the power storage device from being discharged. A power generation device and a power storage device linked to the power system;
A control device according to claim 8,
A power storage system in which the power generation device, the power storage device, and the control device are incorporated in a container. A method for controlling a partial power system that is linked to a power system and includes a power generation device, a power storage device, and a load facility,
When it is determined that the voltage of the power system is smaller than a predetermined threshold,
The connection between the power system and the partial power system is disconnected,
A distribution determination process for determining each power distribution to be supplied from the power generation device and the power storage device to the load facility based on a charging rate of the power storage device;
A control process for controlling each of the power generation device and the power storage device according to the power distribution determined by the distribution determination process and supplying power to the load facility,
A control method for preventing the power storage device from being fully charged or the power storage device from being discharged. A control program for a partial power system that is linked to a power system and includes a power generation device, a power storage device, and a load facility,
When it is determined that the voltage of the power system is smaller than a predetermined threshold,
The connection between the power system and the partial power system is disconnected,
Based on the charging rate of the power storage device, a distribution determination process for determining each power distribution to be supplied from the power generation device and the power storage device to the load facility;
According to the power distribution determined by the distribution determination process, each of the power generation device and the power storage device is controlled, and a control process for supplying power to the load facility is executed by a computer.
A control program for preventing the power storage device from being fully charged or the power storage device from being discharged.

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