JP6108665B2 - Energy saving system - Google Patents

Description

  The present invention relates to an energy saving system that distributes target power of a power control device installed in each facility without exceeding the total target power within a demand time limit of a plurality of facilities.

  In a conventional energy saving system, a target power within a demand time limit (generally 30 minutes) is set in a demand control device, which is a power suppression device, and the maximum demand power is suppressed in units of individual facilities. As such a demand control device, for example, there is a demand control device disclosed in Patent Document 1 with improved demand control followability and stability. Conventionally, in order to suppress the total maximum demand power that is the sum of the maximum demand power of multiple facilities, the total target power value of the multiple facilities is determined in advance, and the sum of the target power values of each facility does not exceed the determined total target power value As described above, the fixed target power value is manually distributed to the demand control devices of each facility.

JP-A-6-78459

  When the total target power management of multiple facilities is performed using the conventional energy-saving system described above, load control is frequently performed at a facility to achieve the target power depending on the operating status, environmental conditions, and location conditions of each facility. In spite of this, there are situations where load control is not performed at other facilities. In order to correct this, conventionally, a method has been adopted in which the target power value is manually reset at the end of the demand time period based on the load control state of the previous demand time period.

  However, for example, when air-conditioning is the load to be controlled, the environmental conditions change frequently, such as the weather conditions where each facility is located and the operating conditions of each facility change. It took time to reset, and in fact, it was rare that resetting was performed frequently. For this reason, in the conventional energy saving system, load control is concentrated on a specific facility depending on the operation status, environmental conditions, and location conditions of each facility, and load control is not performed in a balanced manner.

The present invention has been made to solve such problems,
Collect data from the power suppression devices installed at each facility and the power suppression devices at each facility that control the power consumption within the demand time period defined by an arbitrary unit time below the target power value. Calculate the target power value of each facility so that the total maximum demand power corresponding to the sum of the maximum demand power in the plant does not exceed the set total target power value, and distribute the calculated target power value to the power suppression devices of each facility A central control device, and a power control device and a communication means for communicating data between the central control device ,
The central controller collects the power consumption of the power-saving load at the end of the demand time period as power-saving power from each facility by communication means, so that the total target power value of each facility is less than the total target power value. The power saving potential rate, which is the ratio of the power saving potential power to the power saving potential power capacity that is the power capacity of the possible load, is small, and the target power of the facility having a large margin power that is the difference between the power saving potential power capacity and the power saving potential power is reduced, An energy-saving system was constructed that increased the target power of a facility with a large power-saving rate and no or little surplus power , and redistributed the target power from a facility with a low power-saving rate to a large facility .

  According to this configuration, data is collected from the power suppression device of each facility by the central control device, and the total maximum demand power corresponding to the sum of the maximum demand power in each facility does not exceed the set total target power value. As described above, the target power value of each facility is calculated. The calculated target power value is distributed by the central control device to the power suppression device of each facility via the communication means. For this reason, the central control unit suppresses the total maximum demand power within the demand time limit at multiple facilities within the total target power value, and does not exceed the total target power value of the multiple facilities, so that each facility is not required. It is possible to perform the load control.

  According to this configuration, the central controller reads the power-saving power at the end of the demand time limit from each facility, and the ratio of the power-saving power to the power-saving power capacity that is the power capacity of the power-saving load is large from the facility The target power of each facility is reallocated to the facility. For this reason, the target power is preferentially lowered from facilities with a small ratio of the power saving power capacity to the power saving power capacity, that is, facilities having a power saving load that can greatly reduce power consumption by cutting off the power supply, The frequency of load control in the entire facility can be reduced. Therefore, the load control is not concentrated on a specific facility, and fair load control is performed between facilities, and the frequency of load control in each facility is balanced without changing the total target power value. It becomes possible to set. As a result, when the load capable of saving power is air conditioning equipment and each facility covers a wide area, there is a remarkable effect when there is a difference in the weather conditions of each facility.

  Further, the present invention is characterized in that the power-saving power capacity in each facility can be freely increased or decreased by setting from a central control device via communication means.

  According to this configuration, even if the environmental conditions of each facility change, the power-saving power capacity at each facility can be freely increased or decreased by the setting from the central controller via the communication means, and the power-saving power capacity after the increase / decrease is the target. By setting the power saving capacity at the time of power distribution, it is possible to perform target power distribution reflecting the environmental conditions of each facility. For this reason, for example, when air conditioning is used as a power-saving load, the weather conditions where each facility is located change in addition to the operating conditions of each facility, and even if environmental conditions change frequently. It becomes possible to continue to perform load control in each facility in a balanced and reliable manner. Therefore, it is possible to perform load control that takes into account the characteristics of each facility such as energy efficiency and location conditions due to different types of loads that can save power.

Further, according to the present invention, the central control unit collects the predicted maximum demand power at the end of the demand time period from the power suppression device of each facility at an arbitrary time within the demand time period, and calculates the predicted maximum demand power of each facility. If it exceeds the total target power value sum is a sum predicted maximum demand power is set, and wherein the emit force the cut control command power saving possible load to the power suppression apparatus.

  According to this configuration, the predicted maximum demand power at the end of the demand time period is read out from each facility by the central controller at an arbitrary time within the demand time period, and the sum that is the sum of the predicted maximum demand power of each facility. When the predicted maximum demand power exceeds the set total target power value, the power control device is forcibly issued a power-saving load switching control command. For this reason, when the total maximum demand power is predicted to exceed the total target power value in the middle of the demand time period, the power-saving load is turned off by the operation of the central controller, so that no effort is required. Load control can be performed so that the total maximum demand power does not exceed the total target power value.

  Further, according to the present invention, the central control unit collects the predicted power-saving power at the end of the demand time period from the power control device of each facility at any time within the demand time period by the communication means, and It is characterized in that a cut-off control command is issued in preference to a facility with a small proportion of predicted power saving possible power.

  According to this configuration, the predicted maximum demand power and the predicted power-saving power at the end of the demand time period are read from each facility by the central controller at any time within the demand time period, and the predicted maximum demand power of each facility is read. When the total predicted maximum demand power, which is the sum of the total power, exceeds the set target power value, a cut-off control command is issued in preference to a facility with a small ratio of the predicted power-saving power to the power-saving power capacity, Additional load control is performed so that the ratio of the power saving power to the power saving power capacity of each facility is dispersed as much as possible. For this reason, this additional load control allows the load control to be performed fairly between the facilities without concentrating the load control on a specific facility. In addition, when there is a power usage restriction request based on information such as tight demand for power in the power grid, priority is given to a facility with a low ratio of predicted power-saving power to power-saving power capacity in the additional load control. The same effect is produced by being emitted.

  ADVANTAGE OF THE INVENTION According to this invention, the energy-saving system which can perform load control of each plant | facility without requiring effort without exceeding the total target electric power value of several facilities is provided.

It is a block diagram which shows the outline of a structure of the energy saving system by one embodiment of this invention. It is a block diagram which shows the internal structure of the demand control apparatus used in the energy saving system shown in FIG. It is a block diagram which shows the internal structure of the central control apparatus used in the energy saving system shown in FIG. It is a flowchart which shows the time unit target electric power calculation process performed in the central control apparatus shown in FIG. It is a flowchart which shows the demand calculation process within a time limit performed in the central control apparatus shown in FIG.

  Next, an embodiment of the energy saving system according to the present invention will be described.

  FIG. 1 is a block diagram showing an outline of the configuration of an energy saving system 1 according to the present embodiment.

  Each facility 2 is provided with a controlled load 3 such as an air conditioner, a watt-hour meter 4 for measuring the power consumption of the entire facility, and a demand control device 5 having a function of suppressing the maximum demand power. Yes. The control target load 3 is a power-saving load that can save power by stopping power supply, and is composed of a single or a plurality of loads. The demand control device 5 constitutes a power suppression device that performs control to suppress power usage of the facility 2 within a demand time period defined in an arbitrary unit time, 30 minutes in this embodiment, to a target power value or less. Installed in the facility 2 to suppress the maximum demand power of each facility 2.

  There are a plurality of facilities 2 and are not limited to the three facilities illustrated in the figure. The demand control device 5 of each facility 2 is connected to the central control device 6.

  FIG. 2 is a block diagram showing an internal configuration of the demand control device 5. The demand control device 5 measures the received power data output from the watt-hour meter 4 by the received power measuring unit 7 and predicts the demand power amount at the end of the demand time limit by the calculating unit 9. When the target power set in advance is predicted to be exceeded, the control target load 3 is controlled via the control output unit 10 to prevent the demand power at the end of the demand time limit from exceeding the target power. Perform the action. Further, the power saving possible power measurement unit 8 measures the power used by the control target load 3 as the power saving possible power from the output signal of the watt hour meter 4 or from the output signal of the control target load 3. The calculation unit 9 also performs an operation for predicting and calculating the power saving possible power at the end of the demand period from the power saving possible power measured by the power saving possible power measuring unit 8. As for the power prediction method at the end of the demand time period, there is a method of calculating from the amount of power used until the middle of the demand time period and the rate of increase, for example, the rate of increase in unit time, but either method was used. Even in this case, the details of the present invention are not described because they are not related to the essence of the present invention. The communication unit 11 performs bidirectional communication with the central control device 6.

  FIG. 3 is a block diagram showing the internal configuration of the central controller 6. The central control device 6 is connected to each demand control device 5 via a communication unit 12 capable of bidirectional communication with the demand control device 5 of each facility 2. The communication unit 11 in the demand control device 5 and the communication unit 12 in the central control device 6 constitute communication means for communicating data between the demand control device 5 and the central control device 6. The energy saving system 1 includes a demand control device 5, a central control device 6, and communication means.

  The data storage unit 13 stores data sent from the demand control device 5 of each facility 2 through the communication unit 11 and the communication unit 12. In the condition setting unit 14, the power saving capacity and the increase / decrease of the power saving capacity of each facility 2 are set in advance. The increase / decrease in the power-saving power capacity is a power capacity that can increase or decrease the power-saving power capacity that is initially set in the facility 2 due to subsequent changes in environmental conditions or the like of the facility 2. Based on the data in the data storage unit 13 and the condition setting unit 14, the central controller 6 uses the time-unit target power calculation unit 15 and the intra-time demand calculation unit 16 to perform time-unit target power calculation processing and intra-time demand calculation. The processing is performed as described later, and an operation of transmitting setting data and command data to the demand control device 5 is performed. The power saving capacity in each facility 2 can be freely increased or decreased according to the setting data within the range of the increase or decrease by setting from the central controller 6 via the communication means.

  The central control device 6 collects data from the demand control device 5 of each facility 2 in the above time-unit target power calculation processing, and the total maximum demand power corresponding to the sum of the maximum demand power in each facility 2 is set. The target power value of each facility 2 is calculated so as not to exceed the total target power value thus calculated, and the calculated target power value is distributed to the demand control device 5 of each facility 2. At this time, in the present embodiment, the central control device 6 collects the power consumption of the control target load 3 at the end of the demand time period from each facility 2 by the communication means as the power saving power, and the target power value of each facility 2 is collected. The target power is redistributed from a facility having a low power-saving power ratio to a power-saving power capacity, which is the power capacity of the control target load 3, from a small facility to a large facility so that the sum is equal to or less than the total target power value.

  Further, the central control device 6 uses the communication means to calculate the predicted maximum demand power at the end of the demand time period from the demand control device 5 of each facility 2 at any time within the demand time period in the demand calculation within the time period. When the total predicted maximum demand power that is the sum of the predicted maximum demand power of each facility 2 exceeds the set total target power value, the load control device 5 of each facility 2 A cut control command is forcibly issued via the communication means. At this time, in the present embodiment, the central control device 6 collects the predicted power-saving power at the end of the demand time period from the demand control device 5 of each facility 2 by the communication means at an arbitrary time within the demand time period. The cut-off control command is issued in preference to the facility 2 having a small ratio of the predicted power-saving power to the power-saving power capacity.

  Next, means for distributing the target of the maximum demand power at the end of the demand time period, that is, the time-unit target power to each facility 2 in a balanced manner, which is the first invention, will be described.

  FIG. 4 is a flowchart showing the operation of the time-unit target power calculation process for allocating the time-unit target power to each facility 2 in the central controller 6.

The central controller 6 uses the procedure of S1 to measure the demand power at the end of the demand period measured by the received power measuring unit 7 from the demand control apparatus 5 of each facility 2 after the end of the demand period, and the power saving possible power measuring unit 8 The power-saving power measured in step 1 is collected and stored in the data storage unit 13. It should be noted that the collection timing of each data is preferably immediately after the start of the demand period because the calculation result needs to be reflected in the current demand period. Next, in the procedure of S2, the ratio of the power saving power stored in the data storage unit 13 to the power saving power capacity set in the condition setting unit 14 of each facility 2 is set as the power saving possible rate as a time unit target. Calculated by the power calculator 15. This calculation is performed by, for example, the following formula (1). Note that the power-saving power capacity described below is obtained by adding (subtracting) the increase / decrease.
[Power saving rate] = [Power saving potential] ÷ [Power saving capacity] (1)

  Next, the target power newly allocated to each facility 2 is calculated in the procedure of S3. This calculation is performed as follows, for example.

First, in the facility 2 in which the ratio of the power saving power capacity to the power saving power capacity is less than 1, the surplus power of the power saving power with respect to the power saving power capacity is calculated by the following equation (2).
[Reserved power] = [Power saving capacity]-[Power saving power] (2)

Further, the sum of the surplus power is calculated as the sum total surplus power, and the ratio with the surplus power is calculated as the following margin (3).
[Margin rate] = [Marginal power] ÷ [Total marginal power] (3)

Next, in the facility 2 in which the ratio of the power saving power capacity to the power saving power capacity is 1 or more, the insufficient power saving power relative to the power saving power capacity is calculated by the following equation (4). Normally, there is no shortage of power, but there is a case where shortage of power may occur because the power saving possible power capacity is taken into account (addition / subtraction).
[Insufficient power] = [Power saving power]-[Power saving capacity] (4)

Further, the sum of the shortage power is calculated as the total shortage power, and the ratio with the shortage power is calculated as the following formula (5).
[Insufficient ratio] = [Insufficient power] ÷ [Total insufficient power] (5)

Here, when [total marginal power] ≧ [total total shortage power], the target power of the facility 2 where the surplus power is generated is reduced by the following formulas (6) and (7), and The target power of the generated facility 2 is increased.
[New target power for shortage facilities]
= [Target power until the previous demand time limit] + [Insufficient power] (6)
[New target power for surplus facilities]
= [Target power to the previous demand time limit]-[Margin rate] x [Total power shortage] (7)

Also, if [total power surplus] <[total power shortage], the target power of the facility 2 where the surplus power is generated is reduced by the following formulas (8) and (9), and the power shortage occurs. Increase target power of facility 2.
[New target power for shortage facilities]
= [Target power until the previous demand time limit] + [Insufficient rate] x [Total margin power] (8)
[New target power for surplus facilities]
= [Target power until the previous demand time limit]-[Reserved power] (9)

As a result of the above calculation, the target power can be redistributed in a balanced manner when the insufficient facility 2 and the surplus facility 2 occur. At this time, since the power distributed from the surplus facility 2 having the surplus power to the insufficient facility 2 in which the insufficient power is generated is equivalent, the total target power value does not fluctuate. If all facilities 2 are spare facilities 2, the ratio of the total surplus power to the total power-saveable power capacity, which is the sum of the power-saveable power capacities of the respective facilities 2, is obtained. The target power is distributed by the following equation (10) so that the margin ratio shown is the same ratio.
[New target power for surplus facilities]
= [Target power until the previous demand time limit]-[Power saving capacity]
+ [Power saving capacity] x ([Total margin power] ÷ [Total power saving capacity]) (10)

  After calculating the time unit demand target power of each facility 2 by the calculations of the above formulas (1) to (10), the new target power is transmitted to the demand control device 5 of each facility 2 in the procedure of S4. To do. When the procedure of S4 is completed, the central controller 6 ends the time-unit target power calculation process.

  As described above, in the energy saving system 1 according to the present embodiment, the central controller 6 collects data from the demand control device 5 of each facility 2 in the procedure of S1, and corresponds to the sum of the maximum demand power in each facility 2. The target power value of each facility 2 is calculated in the procedure of S3 so that the total maximum demand power does not exceed the set total target power value. The calculated target power value is distributed to the demand control device 5 of each facility 2 through the communication means by the central control device 6 in the procedure of S4. For this reason, the central control device 6 suppresses the total maximum demand power within the demand time limit in the plurality of facilities 2 within the total target power value, and does not exceed the total target power value of the plurality of facilities 2, and does not require labor. Thus, the load control of each facility 2 can be performed.

  Further, in the energy saving system 1 of the present embodiment, the central controller 6 reads out the power-saving power at the end of the demand time period from each facility 2 in the procedure of S1, and the power-saving that is the power capacity of the load 3 to be controlled. The target power of each facility 2 is redistributed in the procedure of S3 from the facility 2 where the ratio of the power saving possible power to the possible power capacity is small to the large facility 2. For this reason, the target power is given priority from the facility 2 having a small ratio of the power saving power capacity to the power saving power capacity, that is, the facility 2 having the control target load 3 capable of greatly reducing power consumption by cutting off the power supply. The frequency of load control in the entire facility 2 can be reduced. Accordingly, the load control is not concentrated on a specific facility 2, and the load control is performed fairly between the facilities 2. The frequency of load control in each facility 2 without changing the total target power value. Can be set in a well-balanced manner. As a result, when the load to be controlled 3 is an air conditioner and each facility 2 covers a wide area, if the weather conditions of each facility 2 are different, a remarkable effect is achieved.

  Further, in the energy saving system 1 of the present embodiment, even if the environmental conditions of each facility 2 change, the power-saving power capacity in each facility 2 is set to the condition setting unit 8 by the setting from the central control device 6 via the communication means. The target power distribution that reflects the environmental conditions of each facility can be freely increased / decreased within the range of increase / decrease set in advance, and the power saving capacity after the increase / decrease is set as the power saving capacity at the time of target power allocation. Is possible. For this reason, for example, when air conditioning is set as the load to be controlled 3, the environmental conditions frequently change because the weather conditions in which each facility 2 is located change in addition to the operating status of each equipment. However, it is possible to continue to perform load control in each facility 2 in a balanced manner. Therefore, it is possible to perform load control that takes into account the characteristics of each facility such as energy efficiency and location conditions depending on the model difference of the control target load 3.

  Next, means for preventing the total maximum demand power from exceeding the total target power value in the middle of the demand time period, which is the second invention, will be described.

  FIG. 5 is a flowchart showing the operation of the intra-time demand calculation process for preventing the total maximum demand power from exceeding the total target power during the demand time period.

  The central controller 6 determines the maximum demand power (predicted maximum demand) predicted at the end of the demand time period calculated by the calculation unit 9 from the demand control device 5 of each facility 2 at any time within the demand time period in the procedure of S5. Power) and power saving possible power (predicted power saving possible power) are collected and stored in the data storage unit 13. The data collected from each demand control device 5 by the central control device 6 needs to be at the same time. Next, the total predicted maximum demand power, which is the sum of the predicted maximum demand power, is calculated by the intra-time demand calculation unit 16 in the procedure of S6. If the total predicted maximum demand power exceeds the total target power (total target power ≦ total predicted maximum demand power) in step S7 and the determination is NO, the operations after step S8 are performed.

  In the procedure of S8, for example, the forced load control facility 2 that forcibly turns off is determined based on the following rules.

First, the ratio of the predicted power-saving power of each facility 2 stored in the data storage unit 13 and the power-saving power capacity set in the condition setting unit 14 in advance as a power-saving rate is expressed by the following equation (11). To calculate.
[Power saving rate] = [Predicted power saving power] ÷ [Power saving capacity] (11)

Further, the predicted surplus power of each facility 2 is calculated by the following equation (12).
[Predicted margin power] = [Power saving potential capacity] − [Predicted power saving potential] (12)

Then, until the condition shown in the following formula (13) is satisfied, the forced load control facility 2 to be subjected to the forced load control is determined in the order of the low power saving rate, that is, the power saving surplus.
[Total predicted maximum demand power]-[Total target power] ≤ [Total predicted surplus power of forced load control facility] (13)

  After the determination of the forced load control facility 2, the forced load control command is transmitted to the demand control device 5 of each facility 2 through the communication unit 12 in the procedure of S9. When the procedure of S9 is completed, or when the total predicted maximum demand power falls below the total target power (total target power> total predicted maximum demand power) and S7 is YES, the central controller 6 is within the time limit. The demand calculation process is terminated.

  As described above, in the energy saving system 1 according to the present embodiment, as described above, the predicted maximum demand power at the end of the demand time period is the central value from each facility 2 at any time within the demand time period in the procedure of S5. It is read by the control device 6. When the total predicted maximum demand power, which is the sum of the predicted maximum demand power of each facility 2 calculated in the procedure of S6, exceeds the set total target power value compared in the procedure of S7 In the procedure of S9, the demand control device 5 of each facility 2 is forcibly issued a cut control command for the load to be controlled 3. Therefore, even when the total maximum demand power is predicted to exceed the total target power value in the middle of the demand time period, the control of the load to be controlled 3 of each facility 2 is performed by the operation of the central controller 6. The load control can be performed without requiring time and effort so that the total maximum demand power does not exceed the total target power value.

  Further, in the energy saving system 1 of the present embodiment, the predicted maximum demand power and the predicted power-saving power at the end of the demand time period can be obtained from each facility 2 at any time within the demand time period from each facility 2 in the procedure of S5. 6 is read. If the total target maximum power demand, which is the sum of the predicted maximum demand power of each facility 2, exceeds the set total target power value, and the determination in S7 is NO, the power that can be saved in the procedure of S8 A facility 2 having a small ratio of predicted power saving power to capacity is determined as the forced load control facility 2, and a cut-off control command is issued in preference to this facility 2, and power saving possible power for each facility 2 is possible. The additional load control is performed so that the ratio of the above is dispersed as much as possible. For this reason, this additional load control prevents the total sum of the predicted maximum demand power of each facility 2 from exceeding the total target power value within the demand time period, and gives priority to the facility 2 having a power saving margin. Thus, the load control can be performed, and the load control is performed between the facilities 2 without being concentrated on the specific facility 2.

  In the above embodiment, the energy saving system according to the present invention has been described for the case where the load control is performed so that the sum of the maximum demand power in each facility does not exceed the set total target power value. However, the energy saving system according to the present invention is not limited to this, and the total target power value to be set is also limited for load control when there is a power usage restriction request based on information such as the demand power tightness of the power system. By setting the required power value, it can be applied in the same manner, and the same effect can be obtained. In addition, the additional load control in this case also has the same effect as that of the above-described embodiment by giving a cut-off control command in preference to a facility having a small ratio of predicted power-saving power to power-saving power capacity. Is done.

1 ... Energy-saving system 2 ... Facility 3 ... Control target load (load that can save power)
4 ... Electricity meter 5 ... Demand control device (power suppression device)
6 ... Central control device 7 ... Received power measurement unit 8 ... Power saving possible power measurement unit 9 ... Calculation unit 10 ... Control output unit 11, 12 ... Communication unit (communication means)
DESCRIPTION OF SYMBOLS 13 ... Data storage part 14 ... Condition setting part 15 ... Time-unit target electric power calculation part 16 ... In-time demand calculation part

Claims (4)

Collecting data from the power suppression device installed in each facility and controlling the power used within the demand time period defined in arbitrary unit time below the target power value, and the power suppression device of each facility, The target power value of each facility is calculated so that the total maximum demand power corresponding to the sum of the maximum demand power in the facility does not exceed the set total target power value, and the calculated target power value is used as the power suppression device of each facility A central control device that distributes the power to the power control device and communication means for communicating data between the central control device ,
The central control device collects the power consumption of the power-saving load at the end of the demand time period as power-saving power from each facility by the communication means, so that the sum of the target power values of each facility is equal to or less than the total target power value. A facility having a low power-saving rate that is a ratio of the power-saving power to a power-saving power capacity that is a power capacity of the power-saving load and having a large margin power that is a difference between the power-saving power capacity and the power-saving power The target power of the facility having a low power saving rate is increased by increasing the target power of the facility having a large ratio of the power saving possible rate, a large percentage of the power saving possibility, and a facility having no marginal power or a low marginal power. Energy saving system to redistribute . The energy saving system according to claim 1 , wherein the power-saving capacity in each facility is freely increased or decreased by setting from the central control device via the communication unit. The central control unit collects the predicted maximum demand power at the end of the demand time period from the power suppression device of each facility at an arbitrary time within the demand time period, and is a sum total of the predicted maximum demand power of each facility. 3. The power cut-off control command is forcibly issued to the power control device when the predicted maximum demand power exceeds a set total target power value. The energy-saving system described. The central control device collects predicted power saving power at the end of the demand time period from the power suppression device of each facility at an arbitrary time within the demand time period by the communication means, and the predicted power saving for the power saving capacity The energy saving system according to claim 3 , wherein the cut-off control command is issued in preference to a facility having a small proportion of possible power.

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