JP2007143225A - Control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control system which can favorably stabilize the link power at a link point, while maintaining the favorable energy efficiency at a power consumer, regarding the control system which controls the output of a generator which can generate power in cooperation with a power system and can adjust the output of the generator and an accumulation and discharge device which can accumulate and discharge electricity in cooperation with the power system and besides can adjust the output of the accumuation and discharge, at a power consumer who receives power from the power system. <P>SOLUTION: This control system is equipped with a means 11 which monitors the link power at a link point 2 to a power system 50, a means 12 which decomposes the ripple of the link power into a low frequency ripple components and high frequency ripple components, a means 13 which changes the generation output of the generator 20, based on the first output change target value for compensating the low frequency ripple components, and a means 14 which changes the accumulation/discharge output of the accumulation and discharge device 30, based on the second output change target value for compensating the high frequency ripple components. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention provides a power consumer that receives power from an electric power system, a power generation device capable of generating power linked to the power grid and capable of adjusting the power generation output, and capable of storing and discharging linked to the power grid and storing the power. The present invention relates to a control system for controlling output with a storage / discharge device capable of adjusting discharge output.

  For power consumers who have a power load that consumes the power received from the power grid, a distributed power generator such as a cogeneration system that can be connected to the power grid and adjust its power output is installed. There is a case. Such a cogeneration apparatus is normally configured such that the power generation output is controlled based on the electric power demand, heat demand, etc. of the electric power consumer.

  Furthermore, in addition to the above distributed power generators, there are cases where power consumers are installed with storage / discharge devices that perform power storage or discharge in connection with the power system. Such a storage / discharge device is usually a backup that discharges during a power failure to cover the power load of a power consumer, a peak cut that discharges when the power demand of the power consumer is large, and lowers the peak value of the received power, etc. In this way, the storage / discharge output is controlled.

In addition, there is a case in which a natural energy power generation device that generates power linked to an electric power system using natural energy such as sunlight or wind power is installed in a power consumer. Normally, the power generation output cannot be adjusted, and the power generation output fluctuates relatively frequently following changes in natural energy.
Then, if the interconnection power at the interconnection point with respect to the power system fluctuates due to fluctuations in the power generation output of the distributed generator connected to such a power system, the frequency of the power in the power system (hereinafter referred to as “power system frequency”). ”) May not be stabilized at the reference frequency (50 Hz or 60 Hz).
Therefore, as a method of stabilizing the interconnection power of the wind power generator as the natural energy power generator, a storage / discharge device that performs storage / discharge linked to the power system is installed, and the power generation output of the wind power generator is a predetermined value. In the case where the excess is stored in the storage / discharge device when it exceeds the amount, and conversely, when the power generation output is insufficient with respect to the predetermined value, the shortage is discharged from the storage / discharge device, A method of changing the storage / discharge output of the storage / discharge device based on the fluctuation of the power generation output of the wind turbine generator is known (see, for example, Patent Document 1).

JP-A-11-299106

  However, in the method of changing the storage / discharge output of the storage / discharge device based on the fluctuation of the power generation output of the power generation device in order to stabilize the grid power, the storage / discharge in the storage / discharge device is frequently changed according to the fluctuation of the power generation output. As a result, problems such as a decrease in energy efficiency due to power loss associated with storage and discharge of the storage and discharge device occur.

  In addition, if a power generation customer has a distributed power generation device such as a cogeneration device that can adjust the power generation output, control the power generation output of the distributed power generation device based on fluctuations in the grid power. However, it is conceivable to stabilize the grid power, but the frequent change in the power generation output of this distributed power generator causes a decrease in the operating efficiency of the distributed power generator itself. Since the response of output change is relatively low, there is a case where the interconnection power cannot be sufficiently stabilized.

  On the other hand, an electric power company that supplies power to the power grid allows the fluctuation of the grid power at the grid point of the power consumer, and changes the power generation output of the adjustment power generator that manages and manages the power grid. Even when it is configured to stabilize the power system frequency, problems such as instability of the power system frequency due to the low response of the power generation equipment for adjustment and an increase in the maintenance cost of the power generation equipment for adjustment arise.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a power generation device capable of generating power and adjusting the power generation output linked to the power system, and storing and discharging linked to the power system. For power consumers who have installed storage / discharge devices capable of adjusting the storage / discharge output, it is possible to satisfactorily stabilize the grid power at the grid point while maintaining good energy efficiency in the power consumer. It is the point which provides the control system which can be made to do.

In order to achieve the above object, a control system according to the present invention includes a power generation apparatus capable of generating power in conjunction with the power system and adjusting the power generation output in a power consumer receiving power from the power system, and the power system. Is a control system that controls the output of a storage / discharge device capable of storing and discharging and adjusting the stored / discharged output, the first characteristic configuration of which is connected to the power system of the power consumer A grid power monitoring means for monitoring grid power at a point;
The fluctuation of the interconnection power monitored by the interconnection power monitoring means includes a low frequency fluctuation component that is a fluctuation component in a predetermined low frequency area and a high frequency fluctuation component that is a fluctuation component in a predetermined high frequency area. Variable component decomposition means that decomposes into
A power generation output control means for deriving a first output change target value for compensating the low frequency fluctuation component and changing the power generation output of the power generation device based on the first output change target value;
A second output change target value for compensating the high frequency fluctuation component; and a storage / discharge output control means for changing the storage / discharge output of the storage / discharge device based on the second output change target value. In the point.

According to the first characteristic configuration, the first output change target value derived by the power generation output control unit is decomposed from the fluctuation of the interconnection power at the interconnection point with respect to the power system by the fluctuation component decomposition unit. Since the fluctuation component is derived so as to compensate, the fluctuation speed is relatively slow. The power generation output control means can accurately change the power generation output of the power generation device having relatively slow responsiveness based on the first output change target value that fluctuates relatively slowly.
On the other hand, the second output change target value derived by the storage / discharge output control means compensates for the high frequency fluctuation component decomposed from the fluctuation of the interconnection power at the interconnection point with respect to the power system by the fluctuation component decomposition means. Therefore, the fluctuation speed is relatively fast. Then, the storage / discharge output control means can accurately change the storage / discharge output of the power generation device having a relatively fast response of the storage / discharge output based on the second output change target value that fluctuates relatively quickly. .
As a result, the fluctuation of the interconnection power at the interconnection point with respect to the power system is based on the change of the power generation output based on the first output change target value of the power generation device and the second output change target value of the storage / discharge device. It is compensated well by changing the storage / discharge output. Moreover, since the fluctuation | variation of the interconnection power in the interconnection point with respect to the said electric power system is decomposed | disassembled and compensated by the output change of both a power generator and a storage / discharge device, the change width | variety of the power generation output of a power generator and a storage / discharge device Both of the change widths of the storage and discharge outputs are relatively small, and a decrease in energy efficiency associated with the output change can be suppressed.
Therefore, according to the present invention, in a power consumer that has a power generation device linked to the power grid and a storage / discharge device linked to the power grid, while maintaining the energy efficiency of the power consumer at a good level, A control system capable of satisfactorily stabilizing the interconnection power at the point can be realized.

  A second characteristic configuration of the control system according to the present invention is that the electric power consumer is provided with a natural energy power generation device that generates power in conjunction with the power system using natural energy.

  According to the second characteristic configuration, the power generation output linked to the power system, such as a solar power generation device or a wind power generation device, follows the fluctuation of natural energy such as sunlight or wind power. Even when a natural energy power generation device that fluctuates relatively frequently is installed and the fluctuation of the interconnection power at the interconnection point is likely to occur, the control system of the present invention is preferably implemented to improve the energy efficiency of the electric power consumer. It is possible to satisfactorily stabilize the interconnection power at the interconnection point while maintaining a good one.

  The 3rd characteristic structure of the control system which concerns on this invention exists in the point by which the said electric power generating apparatus is comprised with the cogeneration apparatus which generate | occur | produces electric power and heat | fever together.

  According to the third feature configuration, using a cogeneration device that generates power in conjunction with an electric power system, supplying electric power and heat together with a consumer, The stabilization of the interconnection power can be realized.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In the electric power consumer 1 that receives power from the power system 50 shown in FIG. 1, as a power generation device that generates power in conjunction with the power system 50, power generation is performed by a gas engine power generation device, a fuel cell, or the like, and exhaust heat is heated. A cogeneration apparatus 20 capable of generating heat in the form of being recovered as a natural energy generation apparatus 40 such as a solar power generation apparatus or a wind power generation apparatus that generates power using natural energy such as sunlight or wind power. Yes.

  The cogeneration apparatus 20 is configured to be adjustable in such a manner that its power generation output is set to a power generation output command value. This generated power is supplied to at least one of the power load 45 and the power system 50, and the generated heat is supplied by hot water. It is supplied to a heat load 21 utilizing exhaust heat such as a device or a floor heating device.

  On the other hand, the natural energy power generation apparatus 40 is configured such that its power generation output varies according to the amount of natural energy supplied, and this generated power is also supplied to at least one of the power load 45 and the power system 50. The

  In addition, the electric power consumer 1 is provided with a storage / discharge device 30 that can perform storage and discharge in connection with the power system 50 and adjust the storage / discharge output.

  The storage / discharge device 30 is configured to be adjustable in such a manner that the storage / discharge output is set to the storage / discharge output command value, and discharges to at least one of the power load 45 and the power system 50 or receives power from the power system 50. Electric power and the generated power of the cogeneration apparatus 20 and the natural energy power generation apparatus 40 can be stored. The storage / discharge output indicates discharge power when the value is positive, and indicates storage power when the value is negative.

  Further, by adding the control system 10 externally to the cogeneration apparatus 20 and the storage / discharge apparatus 30, the power consumer 1 can be connected to the power system 50 in order to contribute to frequency control of the power system frequency described later. A function of stabilizing the interconnection power at the system point 2 is added to the cogeneration apparatus 20 and the storage / discharge apparatus 30.

The control system 10 includes a connection power monitoring unit 11 that monitors connection power (received power) at the connection point 2 with respect to the power system 50, and fluctuations in connection power monitored by the connection power monitoring unit 11. And a fluctuation component decomposing means 12 for decomposing the low frequency fluctuation component which is a fluctuation component in a predetermined low frequency region and a high frequency fluctuation component which is a fluctuation component in a predetermined high frequency region.
Further, the control system 10 derives a first output change target value for compensating for the low frequency fluctuation component, and changes the power generation output of the cogeneration apparatus 20 based on the first output change target value. Means 13 and a storage / discharge output control means for deriving a second output change target value for compensating the high frequency fluctuation component and changing the storage / discharge output of the storage / discharge device 30 based on the second output change target value 14.

The grid power monitoring means 11 monitors the grid power at the grid point 2 (the power receiving point for the power system 50 of the power consumer 1) where the cogeneration device 20 and the storage / discharge device 30 are linked, The value is passed to the fluctuation component decomposition means 12.
The fluctuation component decomposing means 12 is a low-frequency fluctuation component in a predetermined low-frequency region, using a predetermined band-pass filter, to change the fluctuation of the interconnection power monitored by the interconnection power monitoring means 11 in a predetermined unit time. The frequency fluctuation component is decomposed into a high frequency fluctuation component which is a fluctuation component in a predetermined high frequency region.
The predetermined low wavenumber region is a frequency range set according to the change responsiveness of the power generation output of the cogeneration apparatus 20, and can be set to a range of about 0.01HZ to 0.1HZ, for example. .
The predetermined high frequency range is a frequency range higher than the low frequency range, and is a frequency range set according to the change responsiveness of the storage / discharge output of the storage / discharge device 30, for example, It can be set in the range of 0.1HZ to 1HZ.

  It should be noted that such fluctuations in the interconnection power at the interconnection point 2 cause instability of the power system frequency. If control is performed to suppress fluctuations in the interconnection power, the power system This can contribute to frequency stabilization.

Therefore, the power generation output control means 13 sets the first output change target value to be changed to compensate for the low frequency fluctuation component so as to contribute to the compensation of the low frequency fluctuation component decomposed from the fluctuation of the interconnection power. Deriving and changing the power generation output of the cogeneration apparatus 20 based on the first output change target value in a form of adding the first output change target value to the power generation output command value of the cogeneration apparatus 20, for example.
On the other hand, the storage / discharge output control means 14 is a second output change target value to be changed in order to compensate for the high frequency fluctuation component so as to contribute to the compensation of the high frequency fluctuation component decomposed from the fluctuation of the interconnection power. Is derived, and for example, the second output change target value is added to the storage / discharge output command value of the storage / discharge device 30, and the storage / discharge output of the storage / discharge device 30 is changed based on the second output change target value. To do.

In addition, the relationship between the magnitude of the fluctuation component of the interconnection power and the output change target value is a relationship that is set in advance based on characteristics and operating conditions unique to the cogeneration device 20 and the storage / discharge device 30. Used.
For example, as shown in the graph of the relationship between the fluctuation component (low frequency fluctuation component, high frequency fluctuation component) of the interconnection power and the output change target value illustrated in FIG. 2, the output change target value is represented by a function of the fluctuation component. If the magnitude of the fluctuation component exceeds a predetermined dead zone: A1, A2, the output change target value changes at a constant rate of change: C1, C2 with the deviation as a function. The values of the dead zones A1 and A2 and the rate of change: the values of C1 and C2 are appropriately set based on characteristics and operating conditions unique to the cogeneration apparatus 20 and the storage / discharge apparatus 30.

However, in the cogeneration apparatus 20, when the ratio of the first output change target value is larger than the power that should be output originally commanded by the power generation output command value, the generated power is originally output. As a result, the power generation output command value thus commanded greatly fluctuates and the profit of the installer of this cogeneration device 20 is impaired.
In the cogeneration device 20, the power that should be output is, for example, power that is set to cover as much of the power demand of the power load 45 as possible with the generated power of the cogeneration device 20.

Further, even in the storage / discharge device 30, when the ratio of the second output change target value is larger than the power to be originally stored / discharged instructed by the storage / discharge output command value, the power to be stored / discharged is originally The storage / discharge output command value greatly fluctuates, and the profit of the installer of the storage / discharge device 30 is impaired.
In the storage / discharge device 30, the power that should be stored / discharged is, for example, a backup that is discharged during a power failure to cover the power load 45 of the power consumer 1 or discharged when the power demand of the power consumer 1 is large. Thus, the power is set for the purpose of peak cut to reduce the peak value of the received power from the power system 50.

Therefore, as shown in FIG. 2, the power generation output control means 13 and the storage / discharge output control means 14 determine the magnitudes of the first output change target value and the second output change target value, as shown in FIG. The fluctuation range is limited to be within the fluctuation allowable range set according to the magnitude of the output command value.
That is, the fluctuation tolerance ranges B1 and B2 shown in the graph of FIG. 2 are values that vary according to the power generation output command value provided from the cogeneration device 20 or the storage / discharge output command value provided from the storage / discharge device 30. Yes, for example, a range of ± 3% of the magnitude of the power generation output command value or the storage / discharge output command value can be set.
As a result of the above, if the first output change target value or the second output change target value is to be added to the power generation output command value or storage / discharge output command value that is originally commanded to be output, the cogeneration device 20 and without affecting the installer's profit of the storage / discharge device 30 can contribute to the stabilization control of the interconnection power.

As described above, the control system 10 decomposes the fluctuation of the interconnection power at the interconnection point 2 with respect to the power system 50 into the low frequency fluctuation component and the high frequency fluctuation component, and then the low frequency fluctuation component and the high frequency fluctuation. The first output change target value and the second output change target value for compensating each component separately are derived, and the response is relatively based on the first output change target value derived so as to compensate for the low frequency fluctuation component. The power generation output of the cogeneration apparatus 20 having a slow performance is changed, while the storage / discharge of the storage / discharge apparatus 30 having a relatively fast response based on the second output change target value derived so as to compensate for the high frequency fluctuation component. By changing the output, the power generation output of the cogeneration apparatus 20 and the storage / discharge output of the storage / discharge apparatus 30 are controlled.
As a result, the interconnection power at the interconnection point 2 becomes stable, which can contribute to stabilization of the power system frequency in the power system 50.

<Another embodiment>
(1)
In the said embodiment, about the case where it is set as the value of +/- 3% of the original electric power generation output command value of the cogeneration apparatus 20 and the storage / discharge device 30, and the storage / discharge output command value as the fluctuation | variation tolerance range B1, B2 shown in FIG. Although illustrated, the ratio of ± 3% can be appropriately changed and set. For example, a modification in which a range of ± 5% of the output command value is set as the allowable fluctuation range is possible. Further, the magnitude of the ratio may be changed according to the magnitude of the output command value instead of a fixed value. For example, the ratio can be set such that the ratio when the output command value is 4000 (kW) is set to ± 3%, and the ratio when the output command value is 5000 (kW) is ± 4%.
At this time, if the ratio is set to a large value and the allowable fluctuation range is allowed to increase, for example, in order to compensate for fluctuations in the interconnection power at the interconnection point 2 rather than for its own power load 45. The cogeneration device 20 and the storage / discharge device 30 will be operated, resulting in the disadvantage of the installer that the operating costs of the cogeneration device 20 and the storage / discharge device 30 increase.
On the other hand, the greater the fluctuation tolerance, the greater the ability to compensate for fluctuations in the grid power. Therefore, it is preferable to set the variation allowable range as large as possible within a range that does not disadvantage the installer of the cogeneration device 20 and the storage / discharge device 30.
Alternatively, the variation allowable range may be set regardless of the profit / disadvantage of the installer of the cogeneration apparatus 20 or the storage / discharge apparatus 30. And the electric power company etc. which maintain and manage the electric power system 50, and stabilize the electric power system frequency in the electric power system 50, according to the contribution by the installer of the cogeneration apparatus 20 or the storage / discharge device 30, an installer It is also possible to build a mechanism that compensates for the disadvantages suffered by money.

(2)
In the embodiment and the other embodiment, the power generation output control means 13 and the storage / discharge output control means 14 determine the magnitudes of the first output change target value and the second output change target value as the power generation output command value and the storage output value. Although the configuration has been described in which the variation range is within the allowable variation range set according to the magnitude of the discharge output command value, the present invention is not limited to the above configuration. For example, the power generation output control means 13 and the storage / discharge output control means 14 allow the respective output change target values to be allowed to vary by a predetermined ratio (± 3%, ± 5%, etc.) with respect to the rated output. You may make it the structure restrict | limited to the fluctuation range which is in the range.

(3)
In the above embodiment, as illustrated in FIG. 1, the original power generation output command value is given to the cogeneration apparatus 20, the first output change target value is added to the power generation output command value, and Although the description has been given of the case where the arithmetic processing for deriving the output control value that compensates for the low frequency fluctuation component of the system power is performed, for example, since the thermal load 21 is provided in the cogeneration apparatus 20, The power generation output command value may be given. When a power generation output command value related to heat is given, the power output from the cogeneration apparatus 20 when the operation is performed according to the thermoelectric power generation output command value can also be regarded as the power generation output command value. The control means 13 converts the thermoelectric power generation output command value received from the cogeneration apparatus 20 into the power generation output command value, and uses the same method as in the above embodiment for the power generation output command value to reduce the low frequency of the interconnection power. Control is performed so as to contribute to stabilization of the interconnection power by adding the first output change target value that compensates for the fluctuation component.

(4)
In the above embodiment, in the graph illustrating the relationship between the fluctuation component of the interconnection power and the output change target value illustrated in FIG. 2, the dead zones A1 and A2, the fluctuation allowable ranges: B1 and B2, and the change rates: C1 and C2 However, the absolute value of the dead zone A1 may be different from the value of the dead zone A2, and the value of the fluctuation allowable range B1 and the value of the fluctuation allowable range B2 may be different. The absolute value of the value, the rate of change C1 and the value of the rate of change C2 may be different. In addition, the values of the dead zones A1, A2, the permissible fluctuation ranges: B1, B2, and the change rates: C1, C2 can be set as appropriate. For example, the dead zones A1, A2 may be set to zero.
Moreover, you may set so that the value of dead zone A1, A2, fluctuation | variation permissible range: B1, B2, and change rate: C1, C2 may fluctuate with time. For example, as for the first output change target value for the cogeneration apparatus 20, in the case of a consumer who uses a large amount of power in the morning and evening and uses little power in the daytime, the morning when the cogeneration apparatus 20 uses the cogeneration apparatus 20 itself. In the evening, the dead zones A1 and A2 are increased, the fluctuation tolerance range: B1 and B2 are decreased, and the rate of change: C1 and C2 are decreased, so that they do not contribute much to the stabilization of the interconnection power. During the daytime when the cogeneration system 20 is hardly used, the dead zones A1 and A2 are reduced, the fluctuation tolerance ranges: B1, B2 are increased, and the change rates: C1, C2 are increased, thereby stabilizing the interconnection power. A mode of setting so as to greatly contribute is conceivable.

(5)
In the said embodiment, although the electric power generation output command value of the cogeneration apparatus 20 and the storage discharge output command value of the storage / discharge device 30 were set according to the electric power demand of the electric power load 45 in the electric power consumer 1, The electric power company that manages the power system may set the output command values in consideration of the power load of the entire power consumer connected to the power system.

(6)
In the above-described embodiment, the cogeneration device 20 provided with a generator such as a gas engine power generation device is taken as an example of the power generation device provided to the consumer. Any power generation device such as a cogeneration device 20 provided with a machine or a power generation device that does not generate heat may be used.

  The control system of the present invention includes a power generation device capable of generating power and adjusting the power generation output linked to an electric power system, and a storage and discharge device capable of storing and discharging and adjusting the power storage and discharge output linked to the power system. Can be effectively used as a control system that can satisfactorily stabilize the interconnection power at the interconnection point while maintaining good energy efficiency in the electric power consumer.

Schematic diagram of power system A graph showing the relationship between the fluctuation component of the grid power and the output change target value

Explanation of symbols

1: Electric power consumer 2: Interconnection point 10: Control system 11: Interconnection power monitoring means 12: Fluctuating component decomposition means 13: Power generation output control means 14: Storage / discharge output control means 20: Cogeneration apparatus (power generation apparatus)
30: Storage / discharge device 50: Electric power system

Claims (3)

In a power consumer receiving power from the power system, a power generation device capable of generating power and adjusting the power generation output connected to the power system, and capable of storing and discharging and adjusting the power storage output connected to the power system A control system for controlling the output with a possible storage and discharge device,
Interconnection power monitoring means for monitoring interconnection power at an interconnection point with respect to the electric power system of the electric power consumer;
The fluctuation of the interconnection power monitored by the interconnection power monitoring means includes a low frequency fluctuation component that is a fluctuation component in a predetermined low frequency area and a high frequency fluctuation component that is a fluctuation component in a predetermined high frequency area. Variable component decomposition means that decomposes into
A power generation output control means for deriving a first output change target value for compensating the low frequency fluctuation component and changing the power generation output of the power generation device based on the first output change target value;
A second output change target value for compensating the high frequency fluctuation component; and a storage / discharge output control means for changing the storage / discharge output of the storage / discharge device based on the second output change target value. Control system.   The control system according to claim 1, wherein the electric power consumer is provided with a natural energy power generation apparatus that generates electric power in conjunction with the power system using natural energy.   The control system according to claim 1, wherein the power generation device is configured by a cogeneration device that generates both electric power and heat.

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