JP4190393B2 - Power system - Google Patents

Description

  The present invention relates to a power supply system configured to output commanded power supply power by a power supply device.

  As a power supply device of such a power supply system, a power plant installed as a commercial power source by an electric power company (general electric utility) or a specific scale electric utility, an individual or group other than the electric utility, etc. There are distributed power supplies installed in the facility. When power supply power is output from these power supply devices to a commercial system, the frequency of the power supply power is sent out in accordance with a reference frequency (50 Hz or 60 Hz). As a result, when the total power load by the power load device connected to the commercial system is balanced with the total power source power sent from the power unit, the frequency of power in the commercial system (hereinafter referred to as “commercial system frequency”) (Which may be described) is maintained at the reference frequency.

  However, when the total power source power and the total power load are not balanced, the commercial grid frequency deviates from the reference frequency. Specifically, when the total power load is greater than the total power supply power, the commercial grid frequency is smaller than the reference frequency, and when the total power supply power is greater than the total power load, the commercial grid frequency is greater than the reference frequency. A frequency deviation occurs.

  Maintaining the commercial grid frequency at the reference frequency to prevent the occurrence of frequency deviations as described above is necessary to protect the benefits of power users, so the deviation of the commercial grid frequency from the reference frequency is acceptable. In order to be within the range, the electric power company performs frequency control such that the power source power output from the power plant is increased or decreased to balance the total power source power and the total power load (for example, see Non-Patent Document 1). .

Supervised by Ryuichi Yokoyama, “Liberalization of Electricity and Technology Development”, Tokyo Denki University Press, September 20, 2001, p. 133-135

  In commercial systems, power is not only output from power plants (commercial power) maintained by the power company, but is also output from distributed power supplies installed by individuals and organizations. Yes. And the power source power output from these distributed power supply devices to the commercial system tends to fluctuate due to the circumstances of the individual or group installing them, and in the distributed power supply device from the reference frequency of the commercial system frequency Since no countermeasures have been taken to compensate for the deviation of the power system, the balance between the total power supply and the total power load in the commercial system is lost, and the problem that the commercial system frequency in the commercial system deviates from the reference frequency is expected to occur. .

  The present invention has been made in view of the above problems, and its purpose is to control the frequency of a commercial system frequency without significantly impairing the profit of the installer of the power supply device used for frequency control in the commercial system. It is in the point of providing the power supply system which can perform.

In order to achieve the above object, a first characteristic configuration of a power supply system according to the present invention is a power supply system configured to output a commanded power supply by a power supply device, wherein the power supply device is a commercial system. Connected to the power supply device, the frequency monitoring means for monitoring the commercial system frequency in the commercial system, and the command to compensate for the deviation of the commercial system frequency monitored by the frequency monitoring means from the reference frequency Output control means for adding the commanded power supply power to the power supply device for changing the power fluctuation within a permissible fluctuation range set within a predetermined ratio range with respect to the supplied power supply power. It is in.

According to the first characteristic configuration, the frequency monitoring unit monitors the commercial system frequency in the commercial system, and the output control unit compensates the deviation of the commercial system frequency monitored by the frequency monitoring unit from the reference frequency. Fluctuating power that fluctuates within a permissible fluctuation range set within a predetermined ratio range with respect to the commanded power supply power is added to the commanded power supply power and output from a power supply device such as a commercial power supply or a distributed power supply. Thus, adjustment is made so that the total power supply power and the total power load in the commercial system are balanced. As a result, the deviation from the reference frequency of the commercial system frequency in the commercial system, which occurred when the total power source power and the total power load in the commercial system were deviated, is compensated.
Further, the fluctuation power is set with a fluctuation allowable range set in a predetermined ratio range with respect to the commanded power supply power, and the fluctuation power for compensating for deviation from the reference frequency of the commercial system frequency in the commercial system is By being configured so as to be within the allowable fluctuation range, the power output from the power supply apparatus does not vary greatly from the power supply power commanded to be output originally. In other words, in order to compensate for the deviation of the commercial system frequency from the reference frequency in the commercial system, the fluctuation power is allowed to fluctuate indefinitely, adding a larger fluctuation than the power supply power commanded to be output originally. Although there is a possibility that the power is output from the power supply device, by limiting the fluctuation range of the fluctuating power, the profit of the installer of the power supply device is not greatly impaired.
Therefore, it is possible to provide a power supply system that can perform frequency control of the commercial system frequency without greatly impairing the profit of the installer of the power supply device used for frequency control in the commercial system.

The second characteristic configuration of the power supply system according to the present invention for achieving the above object is that the predetermined ratio range is different depending on the commanded power supply power .

A third characteristic configuration of the power supply system according to the present invention is that the power supply device is configured by a commercial power supply or a distributed power supply .

A fourth characteristic configuration of the power supply system according to the present invention is that the distributed power supply is configured by a cogeneration device that generates both power and heat.

According to the fourth characteristic configuration described above, while supplying both power and heat to a consumer using a distributed power source connected to a commercial system, the profit of the installer of the distributed power source is not significantly impaired. In addition, the deviation of the commercial system frequency from the reference frequency in the commercial system can be compensated.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In the schematic diagram of the commercial system shown in FIG. 1, the commercial system 50 includes a cogeneration power supply system 10, a power generation dedicated power system 20, a power plant 30, and a power consumer who consumes power in the commercial system 50. The power load devices 40 and 41 are connected. The power plant 30 is configured to output the commanded power supply power to the commercial system 50. Further, a large number of power supply systems, power plants, power load devices, and the like may be connected to the commercial system 50.

  In the cogeneration type power supply system 10, the commanded power supply power is output from a power generation device (distributed power supply device) 13 such as a gas engine power generation device, a fuel cell power generation device, a solar power generation device, or a power storage device as a power supply device. The frequency of power in the commercial system 50 to which the power plants 30 and 23 such as a thermal power plant, a hydro power plant, a nuclear power plant, and a wind power plant as commercial power sources that are configured and maintained by an electric power company or the like are connected ( Hereinafter, frequency monitoring means 11 for monitoring (which may also be described as “commercial system frequency”), and compensation for deviation from the reference frequency (50 Hz or 60 Hz) of the commercial system frequency monitored by frequency monitoring means 11 There is provided output control means 12 for adding the fluctuating power to the commanded power supply power and outputting it from the power generator 13. The power generation device 13 is configured by a cogeneration device such as a gas engine power generation device or a fuel cell power generation device that generates both power and heat, and can supply the generated power to the power load device 14 and the commercial system 50. The generated heat can be supplied to the heat load device 15. Further, the output control means 12 may be configured to vary the fluctuating power within a fluctuating allowable range set according to the commanded power supply power.

  The power generation dedicated power supply system 20 is configured to output the commanded power supply power from a power plant (commercial power supply) 23 as a power supply device to the commercial grid 50, and monitors the commercial grid frequency in the commercial grid 50. In order to compensate for the deviation from the reference frequency (50 Hz or 60 Hz) of the commercial system frequency monitored by the means 21 and the frequency monitoring means 21, it is within a variation allowable range set according to the commanded power supply power level. And output control means 22 for adding the commanded power supply power to the commanded power supply power and outputting it from the power plant 23.

  Next, frequency control of the commercial system frequency that can be performed in the cogeneration type power supply system 10 and the power generation dedicated power supply system 20 will be described. The frequency monitoring means 11 and 21 provided in the both power supply systems 10 and 20 will be described. And the output control means 12 and 22 are the same, and in the embodiment described below with reference to FIGS. 1 to 4, the operation of the cogeneration type power supply system 10 will be described. A description of the operation of the system 20 is omitted.

  A power output command value is given to the power generation device 13 of the cogeneration type power supply system 10, and the output control means 12 controls the operation of the power generation device 13 so as to output electric power based on the power output command value. . The frequency monitoring unit 11 monitors the commercial system frequency in the commercial system 50 and passes the value to the output control unit 12. The output control means 12 compares the commercial system frequency monitored by the frequency monitoring means 11 with the reference frequency (50 Hz or 60 Hz), and derives the deviation (deviation amount) of the commercial system frequency from the reference frequency (FIG. 2). Step 100). The presence of a deviation indicates that the total power load and the total power supply power in the commercial grid 50 are not balanced, so that the above-mentioned deviation can be compensated by increasing or decreasing the total power supply power so that they are balanced. It can be performed. Therefore, the output control means 12 derives the fluctuation power to be fluctuated to compensate for the deviation of the commercial system frequency from the reference frequency as the power output fluctuation target value based on the magnitude of the deviation (step 102). The relationship between the magnitude of the deviation of the commercial system frequency from the reference frequency and the derived power output fluctuation target value is characteristic of the power generation equipment 13 (rated output, settling rate, governor deadband, power generation control time constant, governor control). A time constant or the like) or an operation condition required for the power generation facility is used.

  For example, as shown in the graph of the frequency deviation and the power supply output fluctuation target value illustrated in FIG. 3, the power supply output fluctuation target value has a relationship represented by a function of the deviation, and the magnitude of the frequency deviation is a predetermined dead zone: A1. When A2 is exceeded, the power supply output fluctuation target value changes at a constant rate of change C1 and 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 set as appropriate based on characteristics unique to the power generation facility 13, operating conditions required for the power generation facility 13, and the like.

  Therefore, the power supply power to be output from the power generator 13 to the commercial system 50 in order to compensate for the deviation of the commercial system frequency from the reference frequency is commanded by the power commanded by the power supply output command value and the power supply output fluctuation target value. However, if the ratio of the fluctuating power is larger than the power that should be output by the power output command value, the power output from the power generator 13 is The output control means 12 changes the power output fluctuation target value to the power output because the power supply power commanded to be greatly fluctuated and the profit of the installer of the power generator 13 is impaired. Limiting the fluctuation range to be within the allowable fluctuation range set according to the magnitude of the command value, the fluctuation range is derived as a power supply output fluctuation value (step 104). For example, as shown in the graph of FIG. 3, as the allowable fluctuation ranges B1 and B2, for example, a range of ± 3% of the magnitude of the power output command value can be set. As a result, if this power supply output fluctuation value is added to the power supply output command value that is originally commanded to be output, the commercial system frequency is brought close to the reference frequency without impairing the profit of the installer of the power generation device 13. Can contribute to frequency control.

  Next, the output control means 12 adds the power supply output fluctuation value derived in step 104 to the power supply output command value originally given (step 106). Then, with respect to the power supply output command value to which the power supply output fluctuation value is added, the power supply output target value is derived in consideration of the limit value (upper and lower limit values) of the output command value set in the power generation device 13. As an example of the limit value (upper limit value), there is a rated output value of the power generation device 13, which is limited so that an output exceeding the rated output value cannot be commanded. Then, the output control means 12 derives the power supply output control value for actually controlling the power generation apparatus 13 by PI (proportional integration) control with the power supply output of the power generation apparatus 13 as a target for this power supply output target value ( Step 110), and the output control of the power generator 13 is performed.

  Illustrated in FIG. 4 is a graph display of the time transition of the commercial system frequency and the time transition of the power supply output controlled according to the deviation (deviation amount) between the commercial system frequency and the reference frequency (60 Hz). is there. As shown in the figure, when the commercial system frequency monitored by the frequency monitoring means 11 deviates from the reference frequency, a fluctuation is added to the original power supply output command value (indicated by a broken line in the figure) for the power generator 13. I understand that In addition, the fluctuation allowable range (indicated by a one-dot broken line in the figure) is set according to the magnitude of the power supply output command value, and the upper limit value and lower limit value of the power supply output fluctuation value when the power supply output command value is changed, Is set.

  For example, since the commercial system frequency deviates from the reference frequency (60 Hz) at time t1, the next time the control value is given to the power generator 13, the deviation of the commercial system frequency from the reference frequency is compensated. Add the correct power supply output fluctuation value to the power supply output command value. Specifically, since the commercial system frequency is higher than the reference frequency at time t1, that is, the total power output in the commercial system 50 is larger than the total power load, the output control means 12 The power output fluctuation value having a negative value with respect to the power output command value is added to reduce the power output from the power generator 13. As a result, the amount of deviation of the commercial system frequency from the reference frequency can be reduced by balancing the total power supply power and the total power load in the commercial system 50.

<Another embodiment>
<1>
In the above-described embodiment, the case where the variation allowable range is set to a value of ± 3% of the power supply output command value is exemplified, but the ratio of ± 3% can be appropriately changed and set. For example, such a modification that a range of ± 5% of the power supply output command value is set as the allowable fluctuation range is also possible. Further, the magnitude of the ratio may be changed according to the magnitude of the power supply output command value instead of a fixed value. For example, the ratio when the power output command value is 4000 (kW) is set to ± 3%, and the ratio when the power output command value is 5000 (kW) is ± 4%. is there.
At that time, if the ratio is set to a large value and the variation allowable range is allowed to increase, for example, power is output from the power generation device 13 for use in the power load device 14, rather than commercial power. Installation in which power is output from the power generation device 13 to compensate for the deviation of the commercial system frequency from the reference frequency in the system 50, and extra fuel costs and maintenance costs are required for the power generation device 13. The disadvantage of the person. On the other hand, the greater the variation tolerance, the greater the ability to compensate for the deviation of the commercial system frequency from the reference frequency. Therefore, it is preferable to set the allowable fluctuation range as large as possible without causing a disadvantage to the installer of the power generation systems 13 and 20 of the power supply systems 10 and 20.

  Alternatively, the variation allowable range may be set regardless of the profit / disadvantage of the installer of the power supply devices 13 and 23. Then, the power company 13 that maintains and manages the commercial system 50 to maintain the commercial frequency in the commercial system 50 at the reference frequency compensates for the deviation of the commercial system frequency from the reference frequency, It is also possible to construct a mechanism that compensates the disadvantage suffered by the installer with money or the like according to the degree of contribution by the 23 installers.

<2>
In the above embodiment, as illustrated in FIG. 4, a power output command value is given to the power generation facility 13, and the deviation of the commercial system frequency from the reference frequency is compensated for the power output command value. Although the case where the arithmetic processing for adding the power supply output fluctuation value is performed has been described, for example, the power supply system 10 is provided with the thermal load device 15, and therefore the power supply output command value is given to the power generation device 13. Instead, a heat output command value may be given. When a heat output command value is given to the power generation device 13, the power output from the power generation device 13 when the operation is performed according to the heat output command value can be regarded as the power supply output command value. The means 12 converts the heat output command value into a power supply output command value, and the power supply output fluctuation that compensates for the deviation of the commercial system frequency from the reference frequency by the same method as in the above embodiment for the power supply output command value. Control is performed so as to compensate the deviation of the commercial system frequency from the reference frequency by adding the values.

<3>
In the above embodiment, as operations in the cogeneration power supply system 10 and the power generation dedicated power supply system 20, the output control means 12 and 22 provided in both the power supply systems 10 and 20 have the commanded power supply magnitude. However, in the cogeneration type power supply system 10, the fluctuation power is fluctuated without limitation without providing the fluctuation allowance range described above. It does n’t matter. In that case, referring to the operation control flow shown in FIG. 2, step 104 is omitted, and in step 106, the power supply output fluctuation target value derived in step 102 is directly added to the power supply output command value as the power supply output fluctuation value. The Rukoto.

<4>
In the above embodiment, in the graph illustrating the relationship between the frequency deviation and the power supply output fluctuation target value illustrated in FIG. 3, the dead zones A1 and A2, the fluctuation allowable ranges: B1 and B2, and the change rates: C1 and C2, respectively. The absolute values are the same, but 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 and the change thereof may be different. The absolute value may be different between the value of the rate C1 and the value of the change rate C2.

Schematic diagram of commercial system Operation control flow Graph showing the relationship between frequency deviation and power output fluctuation target value Graph showing time transition of commercial system frequency and power output control value

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Power supply system 11 Frequency monitoring means 12 Output control means 13 Power generation device (power supply device)
20 power supply system 21 frequency monitoring means 22 output control means 23 power plant (power supply device)
50 Commercial system

Claims (4)

A power supply system configured to output commanded power supply by a power supply device,
The power supply is connected to a commercial system;
In the power supply device,
Frequency monitoring means for monitoring the commercial system frequency in the commercial system;
In order to compensate for a deviation from the reference frequency of the commercial system frequency monitored by the frequency monitoring means, the fluctuation power that fluctuates within a fluctuation allowable range set in a predetermined ratio range with respect to the commanded power supply power, A power supply system provided with output control means for adding to the commanded power supply power and outputting from the power supply device. The power supply system according to claim 1, wherein the predetermined ratio range is different depending on a magnitude of the commanded power supply power. The power supply system according to claim 1, wherein the power supply device is configured by a commercial power supply or a distributed power supply. The power supply system according to claim 3 , wherein the distributed power source is configured by a cogeneration device that generates both electric power and heat.

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