JP2013143866A - Power supply system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply system that has a commercial power system and a power supply system with a storage battery disposed separately from the commercial power system, and can accurately reduce peak power (implements a peak-cut) in a reference period of power received from the commercial power system.SOLUTION: If power consumption is greater than a predetermined set power, a control section calculates the difference of the power consumption from the power setting, calculates auxiliary power to be supplied from an auxiliary power system to a load system for the amount of the difference in the next divided period, and drives the auxiliary power system to supply the auxiliary power as peak-cut power to the load system, or, if the divided period for which the auxiliary power is determined is a predetermined position in a reference period, determines advance stock power for ensuring auxiliary power for received power in advance and adds the determined power to the auxiliary power to produce peak-cut power.

Description

  The present invention relates to a power supply system that appropriately controls the supply of power from a system different from a commercial power system.

  In recent years, the introduction of a power supply system including a power source that is different from a commercial power system is increasing as a system that supplies power to a power system (referred to as a load system) to which a load is connected. In such a power supply system having a separate power source, a part of the power consumption (demand power) of the load system is covered by the power from the power source, and the power supply from the commercial power system is reduced. ing. In such a power supply system, a configuration including a storage battery that is charged at night when power consumption of the load system is reduced and is discharged during the day has been proposed.

  Next, a power supply system using a conventional storage battery will be described. The power supply system supplies a storage battery, a power conversion device that converts direct current to alternating current or alternating current to direct current, power from the commercial power system and / or power from the storage battery to the load system, A power distribution unit that adjusts the flow of power, such as supplying power from a commercial power system to the storage battery, a power detection unit that detects received power from the commercial power system, and a control unit are provided.

  In the power supply system, an upper limit (hereinafter referred to as set power) of received power (average value) from the commercial power system is set in advance, and when the power consumption of the load system exceeds the set power, Electric power is supplied from the storage battery. That is, the control unit receives information on the received power detected by the power detection unit (hereinafter referred to as power information), and calculates the power consumption of the load system based on the power information. And the said control part compares the power consumption with setting electric power, and determines the electric power supplied to the said load system | strain from the said storage battery. And the said control part controls the said power distribution part, the electric power from the said commercial power system and the electric power from the said storage battery are mixed, and the said load system is supplied. In addition, at night when the power consumption of the load system decreases, the control unit controls the power distribution unit and the power conversion device, and charges the storage battery with power from the commercial power system.

  As described above, in the power supply system, the received power from the commercial power system is suppressed so as not to be larger than the set power (so-called peak cut). And the said electric power supply system is a system which utilizes the electric power stored in the said storage battery at night when there is little electric power demand at the daytime when electric power demand increases.

  Currently, in Japan, the power supplier can use the power usage fee (the amount of received power received from the commercial power grid) by adding the basic fee (contract fee) determined in advance and the metered fee according to the power usage. ) Has been determined. The basic charge is determined based on the maximum peak (hereinafter referred to as peak power) of the received power over the past year. In other words, even if it is a short period in the past year, if there is a prominent power usage record (maximum peak power), it becomes a basic charge based on the maximum peak power for one year and is set high. Since the peak cut is possible by using the power supply system, the maximum peak power can be lowered and the basic charge can be kept low.

  In general, in the commercial power system, the electricity rate is often set at a low price at night when the power demand is low compared to the daytime when the power demand is large. And by adopting the power supply system as described above, part of the daytime power consumption of the load system can be replaced with nighttime electricity that is cheaper than daytime, and the usage fee can be reduced. (For example, refer to JP 2008-306832 A).

  Furthermore, the peak cut as described above suppresses the sum of demand power from exceeding the amount of power supplied (the sum of power supplied to all power consumers by the power supplier), resulting in the occurrence of large-scale power outages. It is also possible to suppress the expansion of facilities in preparation for a major power outage.

JP 2008-306832 A

  The peak power of the commercial power system described above is determined by the average value of power received during a certain period (a reference period, for example, 30 minutes). When the power supply system includes a control method for determining power to be supplied from the storage battery to the load system based on power information from the power detection unit, the time when the power detection unit detects power Then, based on the detected power, there is a difference between the time when power is supplied (peak cut) from the storage battery to the load system. Due to this time lag, effective peak cutting may not be performed.

  More specifically, the power detection unit described above transmits information (power information) of received power from the commercial power system in the divided period obtained by further dividing the reference period to the control unit, and the control unit converts the information into power information. Based on this, the power consumption of the load system is calculated. And the said control part determines the electric energy supplied from the said storage battery based on the said electric power consumption, and makes electric power supply from the said storage battery.

  In the case of such a configuration, the control unit controls the power supplied from the storage battery in the next divided period based on the power consumption of the load system in the immediately preceding divided period. If the power consumption of the load system is always constant, no particular problem occurs. However, in the actual load system, the power consumption often varies in a short time (for example, every time the division period changes). Therefore, when the information on the power consumption of the load system in the previous division period is used for power control in the next division period, the accuracy of peak cut may be reduced.

  For example, if the power consumption of the load system rapidly increases during the last divided period of the reference period, the supply of power from the storage battery to cope with the rapid increase in power consumption is carried over to the next reference period. Therefore, in the previous reference period, supply of power from the storage battery is insufficient, and power received from the commercial power system becomes high. As a result, the peak power may become high, and the basic charge of the power charge may not be suppressed.

  Further, in the divided period, the difference between the power consumption and the set power may exceed the capacity of the power conversion device. At this time, in the next divided period, only the maximum power that can be output by the power converter is supplied from the storage battery. That is, the power exceeding the capacity of the power conversion device becomes power that cannot be peak cut. As a result, reliable peak cutting within the reference period cannot be performed.

  Further, the power supplier determines the amount of power generated in the next reference period based on the supply power supplied during the reference period (the total sum of the power supplied to all the power consumers). When the amount of power generation is determined in this way, the amount of power generation may increase significantly due to fluctuations in the received power in the reference period of the power consumer, which hinders energy saving. Moreover, if peak cut is not performed reliably, demand power may become larger than supply power and may cause a power failure.

  Therefore, the present invention includes a power supply system that is provided separately from the commercial power system and includes a storage battery, and that can accurately suppress peak power (perform peak cut) during a reference period of received power from the commercial power system. The purpose is to provide a supply system.

  In order to achieve the above object, the present invention is connected to a wiring connecting a load system to which a load is connected and a commercial power system, and a peak cut power for reducing the received power from the commercial power system is applied to the load system. An auxiliary power system to supply, a control unit, and a time measuring unit having time information including information on a reference period serving as a reference for calculation of the received power, the control unit in a divided period obtained by dividing the reference period When the power consumption of the load system is larger than a predetermined set power, an auxiliary power that is a difference between the power consumption and the set power is calculated, and the auxiliary power is set as the peak cut power in the next divided period. When the divided period in which the auxiliary power is calculated is a predetermined position in the reference period, a pre-stamp for securing the peak cut power in the latter half of the reference period in advance Provided is a power supply system for controlling the auxiliary power system so as to supply the load system with the peak cut power that is determined by determining the power to be added and adding the preliminary stock power to the auxiliary power in the next divided period To do.

  According to this configuration, it is possible to suppress the received power from the commercial power system by providing a part of the power consumption of the load system with the peak cut power from the auxiliary power system. In addition, by including the pre-stock power in the peak cut power, it is possible to suppress an increase in the received power in the reference period even if the power consumption of the load system varies.

  As a result, the received power during the reference period can be suppressed, and the metered rate of the power rate can be suppressed. In addition, the maximum peak power in the reference period can be suppressed, and an increase in the basic charge of the power charge can be suppressed. Furthermore, the power supply from the power supplier in the reference period can be stabilized, and the power generation facility can be operated stably. In addition, even if the power consumption of the load system fluctuates, the power received from the commercial system can be kept constant, so it is possible to suppress the demand power from exceeding the power supply and suppress the occurrence of power outages. It is.

  The said structure WHEREIN: The said control part may perform addition of the said advance stock electric power in the first half of the said reference period.

  The said structure WHEREIN: While the said control part is provided with the value of the said advance stock electric power, you may call the value of the said advance stock electric power as needed.

  In the above-described configuration, the power detector includes a power detector that detects received power received from the commercial power system, and the control unit detects the received power detected by the power detector in the divided period and the peak cut power. The total power consumption may be the power consumption.

  Further, in the above-described configuration, a power detection unit that detects power consumption of the load system is provided, and the control unit calculates power consumption in the divided period based on power detected by the power detection unit. Good.

  In the above configuration, when the peak cut power exceeds the power that can be supplied from the auxiliary power system, information on the amount of power that exceeds the power that can be supplied is retained as excess power information, and the control The unit may further add peak power to the auxiliary power in the next divided period as peak cut power.

  In the above configuration, the control unit holds information on a maximum value of the power consumption for a certain period, and the control unit also uses a difference between the maximum value of the power consumption and the set power as the preliminary stock power. Good.

  The said structure WHEREIN: The said control part may determine the said preliminary | backup stock electric power so that the said peak cut electric power may become the maximum value of the electric power which can be supplied from an auxiliary power system.

  The said structure WHEREIN: The said auxiliary | assistant electric power system may be provided with the storage battery and the power converter device which converts direct current | flow and alternating current.

  In the above configuration, the control unit charges the storage battery from the commercial power system when the power consumption of the load system is small, and supplies the peak cut power from the storage battery when the power consumption of the load system is large. The auxiliary power system may be controlled.

  In the above-described configuration, the auxiliary power system may include a power generation device. Examples of the power generator include a power generator using a gas turbine and / or a steam turbine, a solar power generator, a wind power generator, and a fuel cell.

  According to the present invention, by supplying preset power from the storage battery at the initial stage of the reference period, the power supplied from the commercial power system in the reference period can be suppressed to the preset power. . Also, when the difference between the power consumption of the load system and the set power is larger than the power that can be supplied from the storage battery, the shortage can be compensated for by making the power supply time from the storage battery longer, so that the peak cut can be made reliably. Can be done.

It is a block diagram of an example of the power supply system concerning the present invention. It is a figure which shows a reference | standard period. It is a figure which shows the power consumption, receiving power, and peak cut power in the division | segmentation period of the intermediate part of a reference | standard period. It is a figure which shows the power consumption in the 1st division | segmentation period of a reference | standard period, receiving power, and peak cut electric power. It is a flowchart which shows the peak cut operation | movement of the electric power supply system concerning this invention. It is a graph which shows the result of having performed the simulation of electric power supply with the electric power supply system of this invention. It is a graph which shows the result of having performed the simulation of electric power supply with the conventional electric power supply system on the same conditions as FIG. It is a block diagram of the other example of the electric power supply system concerning this invention. It is a figure which shows the peak cut operation | movement of the electric power supply system concerning this invention. It is a flowchart which determines the peak cut electric power shown in FIG. It is a block diagram of the further another example of the electric power supply system concerning this invention.

(First embodiment)
Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram of an example of a power supply system according to the present invention. In the following explanation, when there is a description of power consumption, received power, auxiliary power, peak cut power, and pre-stock power, the average of each power over a certain period, unless otherwise specified. It is assumed that a value is used.

  As shown in FIG. 1, the power supply system A is a system that supplies power from a commercial system CS and / or an auxiliary power system BS (storage battery 1) to a load system LS to which loads Ld1 to Ld3 are connected. As shown in FIG. 1, the power supply system A includes a storage battery 1, a DC / AC converter 2, a power distribution unit 3, a power detection unit 4, a control unit 5, and a time measuring unit 6.

  The storage battery 1 is a secondary storage battery that can be repeatedly discharged and charged. Examples of the storage battery 1 include a lithium secondary battery, a nickel hydrogen battery, a nickel cadmium battery, and a lead storage battery. The storage battery 1 is a direct current.

  The commercial system CS and the load system LS are alternating current, and power from the storage battery 1 that is direct current cannot be directly supplied to the load system LS. Therefore, in the auxiliary power system BS, the direct current that is the output of the storage battery 1 is converted by the DC / AC converter 2 into alternating current synchronized with the alternating current flowing through the commercial system CS. The DC / AC converter 2 is a converter that can also convert alternating current into direct current. For example, when the storage battery 1 is charged, the alternating current supplied from the commercial system CS is converted into direct current. The DC / AC converter 2 is controlled by the control unit 5. In the power supply system A, a system including the storage battery 1 and the DC / AC converter 2 is an auxiliary power system BS.

  The power distribution unit 3 is arranged at a branch portion between the commercial power system CS, the auxiliary power system BS, and the load system LS. The power distribution unit 3 connects the commercial system CS and the auxiliary power system BS, and flows power from the commercial power system CS to the load system LS, or supplies power to the load system LS from the commercial power system CS and the auxiliary power system BS. It is a mixing device. Moreover, the power distribution part 3 also performs the operation | movement which flows the electric power from the commercial power grid | system CS to the charge grid | system BS, when charging the storage battery 1. FIG. That is, the power distribution unit 3 is a device for distributing power from the commercial power system CS and / or the auxiliary power system BS.

  Calculation of received power from the commercial power system CS is performed based on a predetermined period (hereinafter referred to as a reference period). Therefore, the time measuring unit 6 has time information IT including information on the reference period and transmits it to the power detection unit 4 and the control unit 5. In addition, the time measuring unit 6 may have a clock function, and may be configured to transmit the current time and the end time of the current reference period to the power detection unit 4 and the control unit 5, or information on the current time as time information IT. The configuration may be such that the power is transmitted to the power detection unit 4 and the control unit 5 and the control unit 5 determines the reference period based on the time information IT. Here, the length of the reference period is 30 minutes, and the control unit 5 sets 00 minutes and 30 minutes of each time as the reference period separation time based on the time included in the time information IT from the time measuring unit 6. Has been decided.

  Moreover, the time measuring part 6 may detect the time and / or the reference period determined by the power supplier (synchronize with the time of the commercial power system CS). As a method for detecting this time and / or the reference period ST, a method of directly receiving from the server of the power supplier or a time when the power supplier is receiving from another system is obtained in the same manner as the power supplier. The method of doing can be mentioned.

  The power detection unit 4 detects the received power from the commercial power system CS. More specifically, the power detection unit 4 detects the received power from the commercial power system CS at a predetermined timing based on the time information IT, and transmits the detected power value to the control unit 5 as power information IP.

  Based on the power information IP from the power detection unit 4, the control unit 5 controls the auxiliary power system BS and the distribution unit 3 so that the received power from the commercial power system CS is equal to or less than a certain power (set power). I have control.

  The control unit 5 controls the operations of the DC / AC converter 2 and the power distribution unit 3 so as to supply power (hereinafter referred to as peak cut power) from the auxiliary power system BS to the load system LS (peak cut operation). . Thereby, the received power from the commercial power system CS in the reference period becomes equal to or less than a certain value, in other words, the maximum peak value of the received power in the reference period is reduced (cut). Moreover, the storage battery 1 may be charged. In this case, the power distribution unit 3 is controlled so that the electric power from the commercial power system CS is directed to the DC / AC conversion device 2, and the AC is converted to DC. / AC converter 2 is controlled.

  The control unit 5 includes a control circuit including an arithmetic device such as a microcomputer. The control unit 5 includes a memory 50 that is a storage device, a power consumption calculation unit 51, an auxiliary power calculation unit 52, a preliminary stock power determination unit 53, and a peak cut power calculation unit 54. The memory 50 is a storage unit for storing data necessary for control of the power supply system A, and does not volatilize even if power is not supplied to a ROM dedicated to calling, a RAM that can be called and written, a flash memory, or the like. The configuration includes a nonvolatile memory and the like. The memory 50 stores data such as set power and pre-stock power. In the following description, it is assumed that these data are included. However, depending on the control method, different data may be required, and the necessary data in that case will be described at that time.

  The power consumption calculation unit 51 calculates received power from the commercial power system CS based on the power information IP from the power detection unit 4 and loads based on the peak cut power calculated by the peak cut power calculation unit 54. The power consumption of the system LS is calculated.

  The auxiliary power calculation unit 52 is a circuit that calculates auxiliary power based on the power consumption of the load system LS calculated by the power consumption calculation unit 51. The auxiliary power calculation unit 52 calculates auxiliary power based on the set power PA stored in the memory 50 and the power consumption of the load system LS.

  The advance stock power determination unit 53 is a circuit that determines advance stock power to be added to the auxiliary power. The control unit 5 determines a large amount of power as the pre-stock power in advance in order to prevent a sufficient peak cut from being impossible in the reference period. Details will be described later.

  Note that the pre-stock power may be recorded in the memory 50 with a predetermined power value, or determined based on the maximum output of the load system BS (for example, the rated value of the DC / AC converter 2). It may be done. In addition, when setting it as the electric power given beforehand, the structure which a user inputs from an operation part not shown may be sufficient, and it may be written so that it might not volatilize in the memory 50 when the apparatus was manufactured. .

  The peak cut power calculation unit 54 calculates the peak cut power supplied from the auxiliary power system BS to the load system LS. The peak cut power calculation unit 54 calculates the sum of the auxiliary power calculated by the auxiliary power calculation unit 52 and the preliminary stock power determined by the preliminary stock power determination unit 53. The pre-stock power may be 0, and in that case, the peak cut power calculation unit 54 may use the auxiliary power as the peak cut power.

  The power consumption calculation unit 51, the auxiliary power calculation unit 52, the pre-stock power determination unit 53, and the peak cut power calculation unit 54 may each be configured by an electric (electronic) circuit and are included in the control unit 5. It may be software that runs on a microcomputer.

  As described above, the power supply system A reduces the received power from the commercial power system CS in the reference period by supplying peak cut power from the auxiliary power system BS to the load system LS (peak cut operation). . Therefore, the control unit 5 adds the preliminary stock power to the auxiliary power at a predetermined timing of the reference period (for example, the first half of the reference period) to obtain peak cut power.

  Next, a reference period serving as a reference for calculating received power from the commercial power system CS will be described with reference to the drawings. FIG. 2 is a diagram illustrating a reference period. As shown in FIG. 2, the reference period ST is a constant interval and is continuous.

The power consumption of the load system LS changes, and changes frequently even during the reference period ST. Therefore, in order to cope with this change in power consumption, the control unit 5 divides the reference period ST into a plurality of divided periods T _m (n: n is a natural number) (m is a natural number of 1 to n), and the divided period T _m The power consumption of each load system LS is calculated. The control unit 5, the power consumption calculation section 51 is computing the power consumption of the load system LS divided period T _m based on the power information IP supplied from the power detection unit 4.

As described above, the power detection unit 4 detects the received power from the commercial power system CS and transmits it as power information IP to the power consumption calculation unit 51 of the control unit 5. The power consumption calculation unit 51 based on the power information IP, and calculate the power consumption of the load system LS of each divided period T _m. For example, a power detection unit 4 is sending the detected power information IP received power at finer timing than division period T _m. In this case, the power consumption calculation unit 51 integrates the power value based on the power information IP calculates the average value of the received power in the divided period T _m, further, the peak cut power value from the peak cut power calculation unit 54 By adding, the power consumption of the load system LS is calculated. Incidentally, other than this, it may be provided with a method for calculating the power consumption (average value) of the division period T _m. Therefore, the power detection unit 4 detects received power at least once every divided period.

  Note that the divided period is obtained by dividing the reference period ST in order to calculate the peak cut power based on the power consumption of the load system LS. The greater the number of divisions, the higher the control accuracy. However, if the division period is too small, the processing capacity of the power distribution unit 3 and the control unit 5 and the capacity of the auxiliary power system BS (mainly the operating speed of the DC / AC converter 2) may be exceeded. The accuracy of control decreases. That is, the division number n is determined in consideration of the capabilities of the power distribution unit 3, the control unit 5, and the auxiliary power system BS so that the capability can be controlled with a certain level of accuracy.

  In addition, it is difficult for a power generation device (not shown) that supplies power to the commercial power system CS to finely vary the power generation amount, and in order to prevent the power supply from being interrupted, the power generation amount is determined based on the maximum power demand. ing. And in the time zone when electric power demand is low, there is much electric power that is generated but not used. Therefore, based on the time information IT, the control unit 5 distinguishes between a time zone in which the power demand is high (daytime time zone) and a time zone in which the power demand is low (night time zone). It also contributes to reducing the burden on the commercial power system by charging the storage battery 1 during times when power demand is low and discharging during times when power demand is high. It contributes to.

  In addition, the power supplier adjusts the power transmission amount (power generation amount) in the next reference period based on the power supply amount in the reference period, that is, the sum of the received power from the commercial power system CS by a plurality of power consumers. doing. In a plurality of power consumers, the time periods when the peak of demand power (power consumption) occurs often overlap. By adopting the power supply system A among a plurality of power consumers, it is possible to reliably reduce the sum of demand power, that is, the sum of power received from the commercial power grid CS by all power consumers. Thereby, an increase in the amount of power generation can be suppressed, energy saving can be achieved, and an increase in size of the power supply facility (such as a transmission line or a substation facility) can be suppressed.

  Furthermore, in a normal commercial power system CS, the amount of power used is charged as the sum of a basic fee and a metered fee that is metered according to the received power. In most cases, the metered charge during the daytime when the power demand is high is higher than during the night when the power demand is low. As described above, performing the peak cut operation is the same as replacing high daytime power with cheap nighttime power, and also has the effect of reducing the usage fee for power consumers. Furthermore, the basic charge is determined by the maximum value of the received power in a certain period. The received power is calculated as the received power in the reference period, and the power supply system A can suppress the maximum value of the received power by supplying the peak cut power from the storage battery 1 to the load system LS. Yes, the increase in basic charges can be suppressed.

  In addition, when the time measuring part 6 is a structure which is not synchronized with the time of the commercial power system CS, the reference period ST of the power supply system A and the reference period SR of the commercial power system CS may be shifted. Even in such a case, if the length of the reference period ST is the same as the length of the reference period SR, the power supply system A can obtain a peak cut effect even if the start and end times are shifted. It is.

  For example, it is assumed that the power supply system A is configured to supply peak cut power including pre-stock power to the load system LS from the auxiliary power system BS in the first half of the reference period ST. As shown in FIG. 2, when the reference period ST of the power supply system A and the reference period SR of the commercial power system CS are shifted, the first half of the reference period ST is the middle stage (depending on the amount of deviation, the second half )become. Even if such a shift occurs, the same effect can be obtained because the peak cut power including the pre-stock power is always supplied in the middle (or the latter half) of each reference period SR of the commercial power system CS. In the following description, it may be simply referred to as a reference period, but it is assumed that it is the reference period ST of the power supply system A unless otherwise described.

  The peak cut operation of the power supply system A will be described with reference to a new drawing. FIG. 3 is a diagram showing power consumption, received power, and peak cut power in the divided period in the middle part of the reference period, and FIG. 4 is a diagram showing power consumption, received power, and peak cut power in the first half of the reference period. It is.

First, a method for calculating the peak cut power in the intermediate portion without considering the pre-stock power will be described. FIG. 3 shows the power consumption P1 _{k−1 to} P1 _{k + 2} of the k-th (k> 2) divided period T _k around the middle of the reference period ST, the power consumption P1 _{k−1 to} P1 _{k + 2} of the load system LS, and the power received from the commercial power system CS. Electric power P2 _{k-1 to} P2 _{k + 2} and peak cut power P3 _{k-1 to} P3 _{k + 2} supplied from the auxiliary power system BS are shown by bar graphs. In each divided period, the target power received from the commercial power system CS is set in advance as the set power PA.

The auxiliary power calculation unit 52 of the control unit 5 is the power supplied from the auxiliary power system BS to the load system LS based on the power consumption P1 _k-1 of the divided period T _k-1 calculated by the power consumption calculation unit 51. A certain auxiliary power P3a is calculated. The auxiliary power P3a is a difference between the power consumption P1 _k-1 and the set power PA. Then, the peak cut power P3 _k divisional period _{T k} and the auxiliary power P3a. That is, the power consumption P1 _k of load system LS divided period _{T k} is the sum of the received power P2 _k and peak shaving power P3 _k from the commercial power system CS.

Further, as in the divided period T _{k + 1} shown in FIG. 3, when the power consumption P1 _{k + 1} of the load system LS is smaller than PA, the peak cut power of the next divided period T _{k + 2} becomes 0, that is, the divided period The power consumption P2 _{k + 1} of T _{k + 2} is the received power P2 _{k + 2} from the commercial power system CS.

Thus, the division period T is also the power consumption of the load system LS of _k-1 P1 _k-1 is longer than than the set power PA, auxiliary power excess in the next division period T _k as peak shaving power P3 _k Since the power is supplied from the grid BS, the excess of the power consumption P1 _{k-1 in} the divided period T _k-1 can be recovered in the next divided period T _k . In this way, the excess power consumption is supplied from the auxiliary power system BS, and the average value of the received power from the commercial power system CS in the entire reference period ST is suppressed from becoming higher than the set power PA.

On the other hand, the auxiliary power P3a calculated based on the power consumption P1 _n of the load system LS in the last divided period (the divided period T _{n in} FIG. 2) of the reference period ST is the peak cut power of the next reference period ST. Used for calculation. In all reference period ST, if power P1 _n of the load system LS divided period T _n are the same, the peak cut power exceeding a reference period ST is no problem because the constant. However, since it actually fluctuates, the peak cut power exceeding the reference period ST also changes, and the received power in the reference period ST also fluctuates.

In particular, if the power P1 _n of the load system LS in the divided period T _n is significantly greater than the set power PA, correction of the excess may not be in the reference period ST including division period T _n, the next reference period Carried over to ST. That is, the average value of the received power from the commercial power system CS in the reference period ST is higher than the set power. Therefore, as described above, the pre-stock power is included in the peak cut power in the first half of the reference period ST.

  As shown in FIG. 4, in the power supply system A, control is performed so that the pre-stock power is included in the power (peak cut power) supplied from the auxiliary power system BS to the load system LS in the second divided period (T2). doing.

As shown in FIG. 4, the second divided period auxiliary power P3a of T _2, as described above, it is determined by the difference between the power consumption P1 ₁ divided period T ₁ and the set power PA. In the second divided period _{T 2} in consideration of the pre-stock power P3b, it determines the peak cut power P3 _2. That is, in the second divided period _{T 2,} supplies plus an auxiliary power P3a and pre stock power P3b, as peak shaving power P3 _2, from the auxiliary power system BS to load system LS.

As described above, the power supplied to the load system LS from the commercial power system CS or the auxiliary power system BS in each divided period of the reference period ST is determined. Note that the reference period ST illustrated in FIG. 4 describes the reference period ST immediately after the start of driving of the power supply system A. Since the reference period ST are those changed continuously, if the reference period ST is other than immediately after start of driving the power supply system A, peak shaving power P3 ₁ of the first divisional period T ₁ of the reference period ST, the immediately preceding It is determined based on the power consumption P1 _n of the _nth load system LS in the reference period ST.

Next, the peak cut operation of the power supply system A will be described with reference to the drawings. FIG. 5 is a flowchart showing the peak cut operation of the power supply system according to the present invention. First, the control unit 5 detects that the ( _k−1 ) th (k is a natural number greater than or equal to 2 and less than n) divided period T _k−1 has ended based on the time information IT from the time measuring unit 6 (step S11). ). When the control unit 5 confirms the end of the division period T _k−1 , the power consumption calculation unit 51 uses the power information IP from the power detection unit 4 to consume the power of the load system LS in the division period T _k−1. P1 _k-1-- is calculated (step S12).

Then, the control unit 5, divided period T _k-1 ended determines whether first divided period T ₁ in the reference period in ST (step S13). Here, detection of how many times the divided period is the reference period ST may be confirmed by providing a counter, resetting the counter immediately after the start of the reference period ST, and counting the end of the divided period. However, it may be recognized based on the time information IT from the time measuring unit 6. It is assumed that the control unit 5 detects based on the time information IT from the time measuring unit 6.

When the completed divided period T _k-1 is the first divided period (Yes in step S13), the control unit 5 determines that the pre-stock power needs to be calculated. And the control part 5 drives the prior stock electric power determination part 53, and draws out the data of prior stock electric power P3b from the memory 50 (step S14). Then, the process proceeds to the next step (auxiliary power determination step, step S15).

On the other hand, when the completed divided period T _k-1 is not the first divided period (in the case of No in step S13) or after determining the preliminary stock power P3b (after step S14), the control unit 5 sets the auxiliary power P3a. Proceed to the calculation step. In the calculation process of the auxiliary power P3a, first, the auxiliary power calculation unit 52 of the control unit 5 calls the set power PA from the memory 5 (step S15). The auxiliary power calculation unit 52 confirms whether or not the power consumption P1 _k-1 of the load system LS in the divided period T _k-1 calculated by the power consumption calculation unit 51 is larger than the set power PA (step S16). .

Set when power _{P1 k-1} of the load system LS of the division period _{T k-1} is smaller than the set power PA (NO in step S16), and the auxiliary power calculation unit 52 an auxiliary power P3a to "0" (Step S17). When the power consumption _{P1 k-1} of the load system LS of the division period _{T k-1} is greater than the set power PA, auxiliary power calculation unit 52, an auxiliary power difference between the power consumption _{P1 k-1} and the set power PA P3a is set (step S18).

Then, the control unit 5 confirms again whether or not the completed divided period T _k-1 is the first time (step S19). When the completed divided period T _k-1 is the first time (in the case of Yes in step S19), the preliminary stock power P3b is not supplied from the auxiliary power system BS to the load system LS in the _second divided period T2. Must not. Therefore, the peak cut power calculation unit 54 adds the auxiliary power P3a calculated by the auxiliary power calculation unit 52 and the preliminary stock power P3b determined by the preliminary stock power determination unit 53, and supplies the sum from the auxiliary power system BS to the load system LS. the peak cut power P3 _k is a power (step S110). In addition, when the finished divided period T _k-1 is not the first time (in the case of No in step S19), the peak cut power calculation unit 54 uses the auxiliary power P3a as the peak cut power P3 because the prior stock power P3b has not been determined. _k (step S111).

Peak shaving power calculation unit 54, Ru stores the peak cut power P3 _k in one memory 50 (step S112). Since the commercial power system CS is alternating current, the power supplied from the auxiliary power system BS to the power distribution unit 3 must also be alternating current. And the control part 5 is based on the peak cut electric power P3 _k memorize | stored in the memory 50, and the time information IT received from the time measuring part 6, The peak cut electric power P3 _k synchronized with the received electric power from the commercial power grid CS The DC / AC converter 2 and the power distribution unit 3 are driven so as to be supplied to the power distribution unit 3 (step S113). Then, the control unit 5 controls the power distribution unit 3 to mix the peak cut power P3 _k from the auxiliary power system BS and the received power P2 _k received from the commercial power system CS and supply power to the load system LS. .

  With the above procedure, the power supply system A supplies peak cut power from the auxiliary power system BS and suppresses the received power from the commercial power system CS in the reference period from exceeding the set power. In addition, in the above-described peak cut operation, the auxiliary power is calculated after determining the pre-stock power. However, these may be performed simultaneously. When the auxiliary power is 0 and the preliminary stock power is not determined, the peak cut power is 0. In this case, the driving process (step S113) of the DC / AC converter 2 is omitted.

  A simulation was performed to confirm the effect of the power supply system A shown above. The simulation result will be described in comparison with a conventional power supply system. FIG. 6 is a graph showing a result of a power supply simulation performed by the power supply system of the present invention, and FIG. 7 is a graph showing a result of a power supply simulation performed by a conventional power supply system under the same conditions as FIG. It is. Note that the conventional power supply system is a power supply system that supplies auxiliary power determined from the power consumption of the load system in the immediately preceding divided period as peak cut power from the auxiliary power system to the load system.

  The simulation conditions shown in FIGS. 6 and 7 are as follows. The reference period is 30 minutes, the reference period is 30 equal parts, that is, one divided period is 1 minute. The power consumption of the load system LS is assumed to vary between 45 kW and 60 kW, and the set power is 40 kW. The simulations shown in FIGS. 6 and 7 are set as a reference period immediately after the start of driving of the power supply system. The bar graphs of FIGS. 6 and 7 are the received power received from the commercial power system CS on the lower side and the peak cut power supplied from the auxiliary power system BS on the upper side.

  As shown in FIGS. 6 and 7, peak cut power is not supplied from the auxiliary power system in the first divided period. The power consumption of the load system in the first divided period is 45 kW. In the conventional power supply system, the difference between the power consumption of the first divided period and the set power is supplied as the peak cut power from the auxiliary power system in the second divided period, so in the second divided period, from the auxiliary power system The supplied peak cut power is 5 kW (the broken line portion in FIG. 7).

  On the other hand, in the power supply system A according to the present invention, the pre-stock power is set to 20 kW. Therefore, in the second divided period in the power supply system A of the present invention, the peak cut power supplied from the auxiliary power system is the difference between the power consumption of the first divided period and the set power of 5 kW and the pre-stock power of 20 kW. The sum, that is, 25 kW (broken line portion in FIG. 6).

  In the power supply system A of the present invention and the conventional power supply system, the average received power from the commercial power system in the reference period was 40 kW in the power supply system of the present invention. Then it became 40.66 kW. That is, in the conventional power supply system, the average of the received power from the commercial power system in the reference period exceeds the set power, but in the power supply system of the present invention, the received power is the set power.

  Thus, by using the power supply system according to the present invention, the received power in the reference period can be accurately suppressed (the peak can be accurately cut). As a result, it is possible to reduce the metered charge of the power charge of the power consumer, and it is possible to suppress the increase in the basic charge by suppressing the power peak. In addition, since the amount of power received in the reference period is suppressed to a constant amount of power, the supply power from the power supplier in the reference period can be stabilized, that is, fluctuations in the amount of power generation can be suppressed. Moreover, it can suppress that supply electric power falls below demand electric power, and can suppress a power failure. And it has the effect which suppresses the equipment expansion for suppressing such a power failure.

  As described above, the peak cut operation by the power supply system may be performed only during a period in which the power consumption of the load system LS exceeds the set power. For example, power may be supplied from the auxiliary power system BS to the load system LS only during the daytime when power consumption increases. Therefore, the control unit 5 is provided with data of the time when the power consumption is increased in the memory 50 in advance, and only when the time when the power consumption is increased based on the time information IT acquired from the time measuring unit 6 is reached. A peak cut operation may be performed. Separately from this, when the power consumption of the load system LS calculated by the power consumption calculation unit 51 exceeds a predetermined value, or the value of the power detected by the power detection unit 4 is predetermined. When the value exceeds the peak value, the peak cut operation may be performed.

  In the power supply system A described above, the peak cut operation has been described on the assumption that the pre-stock power is preset. In the power supply system A according to the present invention, the received power from the commercial power system CS in the reference period can be adjusted by changing the pre-stock power. Therefore, an appropriate method for determining the pre-stock power will be described.

  The prior stock power is power for increasing the peak cut power from the auxiliary power system BS in the first half of the reference period ST in order to suppress the received power from the commercial power system CS in the reference period ST. Therefore, the received power from the commercial power system CS in the reference period ST can be suppressed by increasing the pre-stock power. From this, instead of setting the pre-stock power to a value given in advance, the peak cut power in the second divided period is set to power that can be output by the auxiliary power system BS, The power received from the commercial power system CS can be reduced as much as possible.

  For example, the control unit 5 may set the peak cut power in the second divided period to the upper limit power that can be supplied by the auxiliary power system BS. Here, the upper limit of power that can be supplied by the auxiliary power system BS will be described. As shown in FIG. 1, in the power supply system A, the auxiliary power system BS converts the power of the storage battery 1 into alternating current by the DC / AC conversion device 2. That is, it is not possible to supply power that exceeds the capacity (rating) of the DC / AC converter 2. From this, the rating of the DC / AC converter 2 can be given as the simplest upper limit power that can be supplied by the auxiliary power system BS.

  However, if power is continuously supplied from the storage battery 1 at the rating of the DC / AC conversion device 2, the amount of power stored in the storage battery 1 may be used up in a short time. Therefore, the control unit 5 determines the upper limit of the power that can be supplied from the auxiliary power system BS based on the total number of reference periods in the time zone in which the peak cut operation is performed. Thereby, it is possible to suppress the storage amount of the storage battery 1 from becoming insufficient in the second half of the time period in which the peak cut operation is performed, and to reliably perform the peak cut operation. Thus, by determining the peak cut power of the second divided period, it is possible to make the best use of the peak cut operation capability of the power supply system A.

  Thus, it becomes possible to draw out the capability of the power supply system A by determining the pre-stock power based on the storage capability of the storage battery 1 and the conversion capability (rating) of the DC / AC converter 2.

  Another method for determining the pre-stock power is the following method. In a conventional power supply system that supplies only auxiliary power as peak cut power from the auxiliary power system BS to the load system LS, if the power consumption in the load system LS in the last divided period of the reference period increases, the effect of the peak cut operation May decrease or disappear. Therefore, it is preferable to determine the pre-stock power so that it can cope with the power of the load system LS becoming high during the last divided period.

  Therefore, the control unit 5 stores in the memory 50 the maximum value of power consumption of the load system LS from a certain time (for example, one year) before to the present, and sets the set power from the maximum value of power consumption of the load system LS. The reduced power will be pre-stock power. As long as the load of the load system LS does not exceed the past maximum value, the peak cut can be reliably performed.

  As described above, the efficiency of the peak cut operation of the power supply system A can be increased by determining the pre-stock power. Note that the control unit 5 may determine the pre-stock power by the above-described methods and use any of the pre-stock power determined by each method. Further, in the above-described peak cut operation, the preliminary stock power is included in the peak cut power of the second divided period of the reference period. However, the present invention is not limited to this, and the third and subsequent divided periods are not limited to this. It may be included in the peak cut power. In addition, the pre-stock power may be included in the peak cut power of a plurality of divided periods.

(Second Embodiment)
Another example of the power supply system according to the present invention will be described with reference to the drawings. FIG. 8 is a block diagram of another example of the power supply system according to the present invention, and FIG. 9 is a diagram showing a peak cut operation of the power supply system according to the present invention. The configuration of the power supply system B shown in FIG. 8 is the same as that of the power supply system A shown in FIG. 1 except that the control unit 7 is different, and substantially the same parts are denoted by the same reference numerals and substantially the same. Detailed description of the portion is omitted.

  In the power supply system B, the peak cut power calculated by the peak cut power calculation unit 54 may be higher than the power that can be supplied by the auxiliary power system BS, and the peak cut power may not be sufficiently supplied. Therefore, as shown in FIG. 8, the control unit 7 includes an excess power calculation unit in addition to the memory 50, the power consumption calculation unit 51, the auxiliary power calculation unit 52, the preliminary stock power determination unit 53, and the peak cut power calculation unit 54. 71 is provided.

  The excess power calculation unit 71 determines whether the peak cut power calculated by the peak cut power calculation unit 54 exceeds the upper limit of power that can be supplied by the auxiliary power system BS. If it exceeds, the difference value between the peak cut power and the maximum value of the auxiliary power system BS is added to the excess data PD provided in the memory 50 as the excess power PC, and the maximum power that can be supplied by the auxiliary power system BS is peaked. Cut power.

  The peak cut power calculation unit 54 further has a function of adding power data from the excess data PD to the peak cut power calculated in advance. More specifically, the peak cut power calculation unit 54 checks the excess data PD in the memory 50 when the peak cut power does not exceed the upper limit of power that can be supplied by the auxiliary power system BS. When there is no data in the excess data PD (when the integrated data is 0), the peak cut power calculated by the peak cut power calculation unit 54 is used as the peak cut power as it is. When there is data in the excess data PD, the peak cut power calculation unit 54 adds the excess data PD as peak cut power and sends it to the excess power calculation unit 71.

As shown in FIG. 9, when the peak cut power P3 _{k in the} k-th divided period T _k is larger than the maximum value of power that can be supplied from the auxiliary power system BS, the control unit 7 exceeds the maximum value. Is stored in the memory 50 as excess power PC and added to the peak cut power of the next divided period, the (k + 1) th divided period T _{k + 1} . Depending on the power consumption of the load system LS, excess power PC may occur continuously, and the memory 50 includes excess data PD for integrating the excess power PC.

The peak cut operation of the power supply system B will be described. FIG. 10 is a flowchart for determining the peak cut power shown in FIG. The flowchart of FIG. 10 is sandwiched between the step of storing the peak cut power P3 _k of the flowchart shown in FIG. 5 in the memory 50 (step S112), DC / AC converter 2 of the drive step (Step S113) . Further, the memory 50 is provided with excess data PD for integrating the excess power PC.

First, the control unit 5 calls the peak cut power P3 _k− and determines whether or not it is larger than the upper limit PB of power that can be supplied by the auxiliary power system BS (step S21). If peak cut power P3 _k is larger than the upper limit PB supply to power the auxiliary power system BS (Yes in step S21), and the excess power calculation unit 71 can supply at peak cut power P3 _k and the auxiliary power system BS The excess power PC that is the difference from the upper limit PB of the correct power is calculated (step S22). The excess power calculation unit 71 adds excess power PC to the excess data PD in the memory 50 to obtain excess data PD, which is stored in the memory 50 (step S23). The excess power calculation unit 71 and a peak cut power P3 _k and upper PB of which can be supplied by the auxiliary power system BS power proceeds to (step S24), DC / AC converter 2 driving step (step S113 in FIG. 5).

Also, (No in step S21) when the peak cut power P3 _k is smaller than the upper limit PB of power available, peak shaving power calculation unit 54 reads the excess data PD stored in the memory 50 (step S25), it is determined whether or not the excess data PD is 0 (step S26). If excess data PD is 0 (Yes in step S26), peak shaving power calculation unit 54, as using the peak cutting power P3 _k, the DC / AC converter 2 driving step (step S113 in FIG. 5) move on.

When the excess data PD is not 0 (No in step S26), the peak cut power calculation unit 54 adds the excess data PD and the peak cut power P3 _k to obtain the peak cut power P3 _k (step S27). This is sent to the power calculator 71. Excess power calculation unit 71 peak shaving power P3 _k to determine whether greater than the upper limit PB of which can be supplied by the auxiliary power system BS power (step S28). If peak cut power P3 _k is larger than the upper limit PB supply to power the auxiliary power system BS (Yes in step S28) proceeds to step S22. Also, (No in step S28) when the peak cut power P3 _k is smaller than the upper limit PB supply to power the auxiliary power system BS, peak shaving power P3 _k is intact, the driving of the DC / AC converter 2 It progresses to a process (step S113 of FIG. 5).

By using this peak cut power determination method, when the peak cut power P3 _k of the k-th divided period is larger than the upper limit PB of power that can be supplied by the auxiliary power system BS, the difference is added to the memory 50. In addition, since it can be added to the peak cut power of the next k + 1 and subsequent divided periods, the power supply system B can perform a reliable peak cut operation.

(Third embodiment)
In the power supply systems A and B described above, the power detection unit 4 is configured to detect the received power from the commercial power system CS. Since the control units 5 and 7 are configured to detect the peak cut power based on the power consumption of the load system LS, the power consumption of the load system LS may be detected. FIG. 11 shows a block diagram of still another example of the power supply system according to the present invention.

  As illustrated in FIG. 11, in the power supply system C, the power detection unit 4 c detects the power consumption of the load system LS and transmits the detected power information IP to the control unit 5. In the control unit 5, the power consumption calculation unit 51 calculates the power consumption of the load system LS based on the power information IP. Other parts are the same as those of the power supply system A, and detailed description thereof is omitted.

  According to this configuration, since the power consumption of the load system LS is directly detected, the processing of the control unit 5 can be simplified. Moreover, it is good also as a structure provided with the control part 7 of the electric power supply system B instead of the control part 5. FIG. Also in this case, the power consumption calculation unit 51 calculates the power consumption based on the power information IP.

  In the above configuration, the auxiliary power system BS includes the storage battery 1 and the DC / AC conversion device 2, but is not limited to this, and is not limited to this, and from a power generation device such as a solar power generation device or a gas cogeneration system. A configuration for supplying electric power may be used, or a configuration including these power generation devices and power storage devices may be used.

  Thus, by using the power supply system according to the present invention, the received power in the reference period can be accurately suppressed (the peak can be accurately cut). As a result, it is possible to reduce the pay-as-you-go charge of the power charge of the power consumer, and it is possible to suppress an increase in the basic charge by suppressing the power peak. Moreover, since the amount of power received in the reference period can be reduced, the power supplier can suppress an increase in the amount of power generation. Furthermore, it is possible to suppress the occurrence of a power failure due to an increase in peak power, and it is possible to suppress the facility expansion for suppressing the power failure.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to this content. The embodiments of the present invention can be variously modified without departing from the spirit of the invention.

  The present invention is applied to a power supply system for reducing received power received from a commercial power system, for example, a cogeneration system of an office building or a condominium, a solar power generation system of a general household, a power supply system of a factory, etc. Is possible.

A Power supply system 1 Storage battery 2 DC / AC converter 3 Power distribution unit 4 Power detection unit 5 Control unit 50 Memory 51 Power consumption calculation unit 52 Auxiliary power calculation unit 53 Pre-stock power determination unit 54 Peak cut power calculation unit 6 Timekeeping unit LS Load system BS Auxiliary power system CS Commercial power system

Claims (11)

Auxiliary power system connected to the wiring connecting the load system to which the load is connected and the commercial power system, and supplying peak cut power to the load system for reducing the received power from the commercial power system,
A time measuring unit having time information including information of a reference period serving as a reference for calculation of the received power;
A control unit,
When the control unit has a power consumption of the load system in a divided period obtained by dividing the reference period is larger than a predetermined set power, an auxiliary power that is a difference between the power consumption and the set power is calculated. In the next divided period, the auxiliary power is set as the peak cut power, and when the divided period in which the auxiliary power is calculated is a predetermined position in the reference period, the peak cut power in the latter half of the reference period is set in advance. The pre-stock power to be secured is determined, and control is performed to supply the load power to the load system as the peak cut power obtained by adding the pre-stock power to the auxiliary power in the next divided period. Power supply system.   The power supply system according to claim 1, wherein the control unit adds the preliminary stock power in the first half of the reference period.   The power supply system according to claim 1, wherein the control unit includes the value of the pre-stock power and calls the value of the pre-stock power as necessary. A power detection unit for detecting the received power received from the commercial power system;
The power supply according to any one of claims 1 to 3, wherein the control unit uses the sum of the received power detected by the power detection unit in the divided period and the peak cut power as the power consumption. system. A power detection unit for detecting power consumption of the load system;
The power supply system according to any one of claims 1 to 3, wherein the control unit calculates power consumption in the divided period based on power detected by the power detection unit.   When the peak cut power exceeds the power that can be supplied from the auxiliary power system, information on the amount of power that exceeds the power that can be supplied is retained as excess power information, and the control unit further includes: The power supply system according to any one of claims 1 to 5, wherein a peak cut power is obtained by adding the excess power to the auxiliary power in the next divided period.   The control unit holds information on a maximum value of the power consumption for a certain period, and the control unit sets a difference between the maximum value of the power consumption and the set power as the preliminary stock power. The power supply system according to claim 6.   The power supply system according to any one of claims 1 to 5, wherein the control unit determines the preliminary stock power so that the peak cut power becomes a maximum value of power that can be supplied from an auxiliary power system.   The power supply system according to any one of claims 1 to 8, wherein the auxiliary power system includes at least a storage battery and a power converter that converts direct current and alternating current.   The control unit charges the storage battery from the commercial power system when the power consumption of the load system is small, and supplies the peak cut power from the storage battery when the power consumption of the load system is large. The power supply system according to claim 9, wherein the power supply system is controlled.   The power supply system according to any one of claims 1 to 10, wherein the auxiliary power system includes a power generation device.

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