JP4540538B2 - Power supply output fluctuation control device - Google Patents

Description

  The present invention relates to a power supply output fluctuation control apparatus for performing fluctuation control of power supply power output from a power supply apparatus connected to a commercial system.

  As power supply devices connected to the commercial grid, power companies (general electric utilities) and specific-scale electric utilities, etc. installed as commercial power sources, individuals and groups other than electric utilities, There are distributed power supplies installed in various facilities. When power supply power is output from these power supply devices to a commercial system, the frequency of the power supply power is sent to match the 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 supply power is not only output from power plants maintained by power companies, but is also output from distributed power supply devices installed by individuals and organizations. The power supply power output from these distributed power supply devices to the commercial system tends to fluctuate due to the circumstances of the individual or organization installing them, and the output target value of the distributed power supply varies with the fluctuation of the commercial system frequency. It has been decided regardless. Since the commercial grid frequency is determined by the balance between the total power supply power and the total power load in the commercial grid, the commercial grid frequency is likely to be disturbed if there are few generators that correct this when the commercial grid frequency fluctuates. , There may be disadvantages for consumers and the entire grid.

  The present invention has been made in view of the above problems, and an object thereof is to provide a power output fluctuation control device that can contribute to frequency control of commercial system frequencies.

The characteristic configuration of the power output fluctuation control device according to the present invention for achieving the above object is to generate both power and heat , supply the generated power to the power load device, and supply the generated heat to the heat load device. The output command value for the cogeneration device is output from the generator when the operation is performed according to the output command value for the generator provided in the cogeneration device or the heat output command value supplied to the thermal load device. Power output command value,
Frequency monitoring means for monitoring the commercial system frequency of the commercial system in which the output command value the cogeneration system configured to power the power output by the generator based on is connected,
Power supply output fluctuation target value deriving means for deriving a power supply output fluctuation target value for compensating for deviation from a reference frequency of the commercial system frequency monitored by the frequency monitoring means;
Power supply output fluctuation target value output means for outputting the power supply output fluctuation target value derived by the power supply output fluctuation target value deriving means to the cogeneration apparatus .

According to the above characteristic configuration, the frequency monitoring means monitors the commercial system frequency in the commercial system to which the cogeneration device configured to output the power source power based on the output command value is connected to the power generator, The output fluctuation target value deriving means derives a power supply output fluctuation target value for compensating for deviation from the reference frequency of the commercial system frequency monitored by the frequency monitoring means, and the power output fluctuation target value output means is the power supply By outputting the power supply output fluctuation target value derived by the output fluctuation target value deriving means to the cogeneration apparatus , the total power supply power and the total power load in the commercial system can be brought close to a balanced state. As a result, when power and heat are supplied to the consumer using a cogeneration system connected to the commercial system, the total power supply power and total power load in the commercial system are different. The deviation of the commercial system frequency from the reference frequency in the commercial system is compensated. In addition, the power output fluctuation control device of the present invention has a form capable of controlling the power output of the cogeneration device from the outside, that is, it can be added as an external device to the cogeneration device , A function that can contribute to frequency control of the commercial system frequency can be added to the cogeneration apparatus .

The characteristic configuration of the power supply output fluctuation control device according to the present invention is such that the power supply output fluctuation target value output means outputs so that the power supply output fluctuation target value is directly added to the output command value in the cogeneration apparatus . There is in point to do.

According to the characteristic configuration, the power output fluctuation target value output means outputs the power output fluctuation target value so that the power output fluctuation target value is directly added to the original output command value of the cogeneration apparatus. The value can be prevented from becoming a disturbance factor on the cogeneration system side.

The characteristic configuration of the system according to the present invention is as follows:
A cogeneration device that generates both electric power and heat,
With the power output fluctuation control device described above,
A system that supplies power generated by the cogeneration device to a power load device to which power is supplied from a commercial system via the commercial system, and supplies heat generated by the cogeneration device to a heat load device,
An output command value for the cogeneration device is output from the generator when operation is performed according to an output command value for a generator provided in the cogeneration device or a heat output command value supplied to the thermal load device. Power output command value
The commercial power system frequency in the commercial power system is monitored by the frequency monitoring means of the power output fluctuation control device, and the power output fluctuation target value derived by the power output fluctuation target value deriving means is output as the power output fluctuation target value output. Output to the cogeneration device by means,
The generator of the cogeneration apparatus generates electric power according to the output command value and the power supply output fluctuation target value and supplies the electric power to the power load apparatus .

According to the above characteristic configuration, while supplying both power and heat to the consumer using a cogeneration device connected to the commercial system, as described above, from the reference frequency of the commercial system frequency in the commercial system. Deviations 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, a power supply device 20 as a cogeneration device, a power plant 30, and power load devices 22 and 40 that consume power in the commercial system 50 are connected to the commercial system 50. ing. Note that a larger number of power supply devices 20, power plants 30, power load devices 40, and the like may be connected to the commercial system 50.

  The power supply device 20 as a cogeneration device that generates heat and electric power together has a standard configuration in which power supply power based on an output command value is output from a generator 21 such as a gas engine power generation device. The generated electric power is supplied to at least one of the electric power load device 22 and the commercial system 50, and the generated heat is supplied to an exhaust heat utilization type heat load device 23 such as a hot water supply device or a floor heating device.

  Further, by adding the power supply output fluctuation control device 10 externally to the power supply device 20, a function that can contribute to frequency control of a commercial system frequency described later is added to the power supply device 20. The power supply output fluctuation control device 10 includes a frequency monitoring unit 11 that monitors a commercial system frequency in a commercial system 50 to which the power supply device 20 is connected, and a reference frequency (the commercial system frequency monitored by the frequency monitoring unit 11 ( Power supply output fluctuation target value deriving means 12 for deriving a power supply output fluctuation target value for compensating for a deviation from 50 Hz or 60 Hz), and the power supply output fluctuation target value derived by the power supply output fluctuation target value deriving means 12 Power supply output fluctuation target value output means 13 for output to 20. The power supply output fluctuation target value deriving means 12 is provided with the output command value of the power supply device 20.

The frequency monitoring unit 11 monitors the commercial system frequency of the voltage in the commercial system 50 and passes the value to the power supply output fluctuation target value deriving unit 12.
The power output fluctuation target value deriving unit 12 compares the commercial system frequency monitored by the frequency monitoring unit 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. . 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. However, if the control is performed so that the total power supply power is increased and decreased to balance both, Compensation can be performed. Accordingly, the power supply output fluctuation target value deriving means 12 supplies the fluctuation power to be varied in order to compensate for the deviation of the commercial system frequency from the reference frequency in order to contribute to the compensation of the deviation based on the magnitude of the deviation. Derived as the output fluctuation target value.

Specifically, the relationship between the magnitude of the deviation of the commercial system frequency from the reference frequency and the power output fluctuation target value is a characteristic unique to the generator 21 (rated output, settling rate, power generation control time constant, governor control). A time constant or the like) or a preset relationship based on the operating condition required for the generator 21 is used.
For example, as shown in the graph of the relationship between the frequency deviation illustrated in FIG. 2 (deviation from the reference frequency of the commercial system frequency) and the power supply output fluctuation target value, the power supply output fluctuation target value has a relation represented by a function of deviation. Yes, when the magnitude of the frequency deviation exceeds a predetermined dead zone: A1, A2, the power supply output fluctuation 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 set as appropriate based on characteristics unique to the generator 21, operating conditions required for the generator 21, and the like.

However, when the ratio of the power supply output fluctuation target value is larger than the power that should be originally output commanded by the output command value, the power output from the generator 21 is the power supply commanded to be output originally. If it fluctuates greatly from electric power, the profit of the installer of this generator 21 will be impaired.
Therefore, as shown in FIGS. 2 and 3, the power supply output fluctuation target value deriving means 12 sets the magnitude of the power supply output fluctuation target value within the fluctuation allowable range set according to the magnitude of the output command value. Limited to a certain range of fluctuation. That is, the fluctuation allowable ranges B1 and B2 shown in the graph of FIG. 2 are values that vary according to the output command value provided from the power supply device 20, and are, for example, a range of ± 3% of the magnitude of the output command value. Etc. can be set. As a result, if the power supply output fluctuation target value is added to the output command value that is originally commanded to be output, the commercial system frequency is set to the reference frequency without impairing the installer's profit. Contributes to frequency control to bring it closer.

Below, the power supply output control of the generator 21 performed in the power supply device 20 is demonstrated.
In the power supply device 20, the power supply output fluctuation target value output from the power supply output fluctuation control apparatus 10 is directly added to the original output command value in the adder 1, and an output control value as shown in FIG. 3 is obtained. That is, the power supply output fluctuation target value is added to the output command value before other processing as will be described later is performed on the output command value. Therefore, it is possible to prevent the power supply output fluctuation target value output from the power supply output fluctuation control apparatus 10 to the power supply apparatus 20 from being a disturbance factor in the power supply apparatus 20. Further, the power supply output fluctuation target value output means 13 of the power supply output fluctuation control apparatus 10 outputs the output command value in a form that matches the signal format of the output command value so that it can be added to the output command value in the power supply apparatus 20. To do. For example, the power supply output fluctuation target value is output as an analog signal of 4 to 20 mA and 0 to 5V.
Next, the subtractor 2 subtracts the actual output power value indicating the current power supply output from the generator 21 from the output of the adder 1 to reduce the frequency deviation by how much the current power output is. A deviation indicating whether the power output needs to be varied is derived.

  The gain setting unit 3 converts the deviation, which is calculated by the subtracter 2 and represents the amount of change in power supply power, into the engine speed. Further, the subtractor 4 derives how much the rotational speed of the current engine speed of the generator 21 is relative to the rated speed. Then, the subtracter 5 subtracts the output of the subtracter 4 from the output of the gain setting device 3 and derives a command value for the engine rotational speed given to the generator 21 in order to reduce the frequency deviation.

  The gain setter 6 is set with the settling rate of the generator 21, and converts the engine speed input from the subtractor 5 into a fuel amount command signal (governer opening). Thereafter, the low value selector 7 determines the minimum value of the fuel amount command signal obtained by the gain setting device 6 or the load limiter control signal obtained by adding the fuel amount command signal by an amount corresponding to several percent to 10% load. The fuel-related valve of the generator 21 is controlled as a governor command value. Then, desired power supply power is output from the generator 21.

  As described above, the power supply output fluctuation control device 10 derives the power supply output fluctuation target value for reducing the frequency deviation generated in the commercial system 50 and outputs the power supply output fluctuation target value to the power supply device 20. In the power supply device 20, the operation control of the generator 21 is performed with the output control value obtained by adding the power supply output fluctuation target value to the original output command value. As a result, the total power supply power and the total power load in the commercial grid 50 approach a balanced state, and the commercial grid 50 generated when the total power supply power and the total power load in the commercial grid 50 are deviated. The deviation of the commercial system frequency from the reference frequency is compensated.

<Another embodiment>
<1>
In the above embodiment, the variation allowable ranges B1 and B2 shown in FIG. 2 and FIG. 3 are exemplified as a value of ± 3% of the original output command value of the power supply device 20, but the ratio of ± 3% is shown. 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 variation allowable range is allowed to increase, for example, power is output from the generator 21 for use in the power load device 22, rather than commercial power. Installation in which power is output from the generator 21 to compensate for deviation of the commercial system frequency from the reference frequency in the system 50, and the generator 21 needs extra fuel costs, maintenance costs, and the like. 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 variation allowable range as large as possible without causing a disadvantage to the installer of the generator 21 of the power supply device 20.

  Alternatively, the variation allowable range may be set regardless of the profit / disadvantage of the installer of the power supply device 20. Then, an electric power company or the like that maintains and manages the commercial system 50 and maintains the commercial frequency in the commercial system 50 at the reference frequency is determined by the installer of the power supply device 20 when the deviation from the reference frequency of the commercial system frequency is compensated. Depending on the degree of contribution, it is also possible to construct a mechanism that compensates the disadvantage suffered by the installer with money or the like.

<2>
In the embodiment and the other embodiment, the power output fluctuation target value deriving unit 12 seems to have the magnitude of the power output fluctuation target value within the allowable fluctuation range set according to the magnitude of the output command value. Although the configuration limited to such a fluctuation range has been described, the present invention is not limited to the above configuration. For example, the power supply output fluctuation target value deriving means 12 has the magnitude of the power supply output fluctuation target value within a fluctuation allowable range of a predetermined ratio (± 3%, ± 5%, etc.) with respect to the generator rating. You may make it the structure restrict | limited to such a fluctuation range.

<3>
In the above-described embodiment, as illustrated in FIG. 1, the original output command value is given to the generator 21, and the power output fluctuation target value is added to the output command value. Although the case where the arithmetic processing for deriving the output control value that compensates the deviation from the frequency is performed has been described, for example, since the power load device 23 is provided with the thermal load device 23, An output command value related to heat may be given instead of an output command value related to electric power. When a heat output command value is given to the generator 21, the power output from the generator 21 when the operation is performed according to the heat output command value can be regarded as the output command value. The target value deriving means 12 converts the heat output command value received from the power supply device 20 into the output command value, and the output command value is obtained from the reference frequency of the commercial system frequency by the same method as in the above embodiment. Control is performed so as to compensate for the deviation of the commercial system frequency from the reference frequency by adding output control values that compensate for the deviation.

<4>
In the embodiment described above, in the graph illustrating the relationship between the frequency deviation and the power supply output fluctuation 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, 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. The values of the dead zones A1 and A2, the allowable fluctuation ranges: B1 and B2, and the change rates: C1 and C2 can be set as appropriate. For example, the dead zones A1 and A2 may be zero.
In addition, the dead zones A1 and A2, the allowable fluctuation ranges: B1 and B2, and the change rates C1 and C2 may be set so as to change depending on the time. For example, 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 dead zones A1 and A2 are increased in the morning and evening when the power supply device 20 is used, and the fluctuation tolerance range : B1 and B2 are made small, and change rates: C1 and C2 are made small so as not to contribute much to the frequency control of the commercial system frequency, and in the daytime when the power supply device 20 is hardly used by itself, the dead zone A1 , A2 may be set to be small so as to greatly contribute to the frequency control of the commercial system frequency by increasing the allowable fluctuation ranges B1 and B2 and increasing the change rates C1 and C2.

<5>
In the above embodiment, the power supply device 20 provided with the generator 21 such as a gas engine power generation device has been described as an example. However, the power supply device 20 provided with another power generator such as a fuel cell is described. It may be.

  The power supply output fluctuation control device of the present invention can be used to maintain the commercial system frequency in the commercial system at the reference frequency.

Schematic diagram of commercial system 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 output fluctuation control apparatus 20 Power supply apparatus 50 Commercial system 11 Frequency monitoring means 12 Power supply output fluctuation target value derivation means 13 Power supply output fluctuation target value output means

Claims (3)

An output command value for a cogeneration device that generates electric power and heat together, supplies the generated power to the power load device, and supplies the generated heat to the heat load device is an output command for a generator provided in the cogeneration device. Value, or an output command value of power output from the generator when operation is performed according to a heat output command value supplied to the thermal load device,
Frequency monitoring means for monitoring the commercial system frequency of the commercial system in which the output command value the cogeneration system configured to power the power output by the generator based on is connected,
Power supply output fluctuation target value deriving means for deriving a power supply output fluctuation target value for compensating for deviation from a reference frequency of the commercial system frequency monitored by the frequency monitoring means;
A power supply output fluctuation control device comprising power supply output fluctuation target value output means for outputting the power supply output fluctuation target value derived by the power supply output fluctuation target value deriving means to the cogeneration apparatus. The power supply output fluctuation target device according to claim 1, wherein the power supply output fluctuation target value output means outputs the power generation output fluctuation target value so as to be directly added to the output command value in the cogeneration apparatus. A cogeneration device that generates both electric power and heat,
A power output fluctuation control device according to claim 1 or 2,
  A system that supplies power generated by the cogeneration device to a power load device to which power is supplied from a commercial system via the commercial system, and supplies heat generated by the cogeneration device to a heat load device,
An output command value for the cogeneration device is output from the generator when operation is performed according to an output command value for a generator provided in the cogeneration device or a heat output command value supplied to the thermal load device. Power output command value
The commercial system frequency in the commercial system is monitored by the frequency monitoring means of the power output fluctuation control device, and the power output fluctuation target value derived by the power output fluctuation target value deriving means is output as the power output fluctuation target value output. Output to the cogeneration device by means,
A system that generates electric power according to the output command value and the power output fluctuation target value with the generator of the cogeneration apparatus and supplies the electric power to the power load apparatus.

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