Power system stabilizer, power system stabilization method, and program

Abstract

To provide a power system stabilizer capable of providing compensation power depending on variation in frequency of a power system.SOLUTION: A power system stabilizer comprises: a frequency detector for detecting a system frequency of an AC power system; a calculation unit for calculating a frequency command value for adjusting a rotation speed of a rotary machine on the basis of the system frequency; and a power converter that is provided between the AC power system and the rotary machine and adjusts the rotation sped of the rotary machine on the basis of the frequency command value. The rotary machine is a compressor for an air conditioner. The calculation unit calculates the frequency command value by correcting a rotation-speed command value output by a controller of the air conditioner, in proportion to variation in the system frequency.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to a power system stabilization device, a power system stabilization method, and a program. [Background technology]

[0002] In a power system, power plants operate in a governor-free manner in response to power demand, instantly adjusting power generation output to maintain the frequency of the power transmission and distribution system. Power demand in offices, factories, and ordinary homes fluctuates from moment to moment. When power demand in the power transmission and distribution system exceeds power supply, the frequency of the power transmission and distribution system drops below a reference value (e.g., 50 Hz or 60 Hz). Conversely, when power supply exceeds power demand, the frequency rises above the reference value. Power plants adjust the power generation according to frequency to balance supply with the ever-changing demand (see, for example, Patent Document 1). When adjustment is performed ideally, the frequency matches the reference value.

[0003] There is a limit to the range of fluctuations in power supply and demand that can be adjusted using governor-free operation. For this reason, long-term fluctuations in power demand, such as between daytime and nighttime, are handled by starting or stopping additional power plants, and demand that fluctuates from moment to moment is maintained within the range that can be adjusted using governor-free operation.

[0004] Governor-free operation thus plays a central role in balancing supply and demand in power grids, but generator inertia also helps adjust to constantly fluctuating demand. Generator inertia represents the kinetic energy of the rotors of a power plant's generator and turbine. The rotor accelerates and decelerates depending on the difference between turbine input and electrical output. If the difference is negative, the rotor's kinetic energy is released, reducing the rotational speed; conversely, if the difference is positive, the rotational speed increases. In other words, when the rotor's rotational speed (≒ frequency) changes, kinetic energy is released to compensate for (suppress) the change in rotation, according to the equation of motion. For example, if the grid frequency drops due to increased power demand, the rotor speed also drops in sync with the grid frequency. In this case, if the inertia is large, more kinetic energy is released to compensate for the increased demand, reducing the fluctuation in the power grid frequency. In this way, generator inertia is important for preventing frequency fluctuations.

[0005] As we move towards a decarbonized society, the proportion of variable power generation such as solar and wind power will increase year by year. To accommodate these fluctuations in power generation, we must improve governor-free operation capabilities and generator inertia, while also simultaneously improving our ability to adjust supply and demand on a moment-by-moment basis.

[0006] The supply and demand adjustment of the power system is carried out based on the frequency of the power system. One of the simplest models of the frequency f of the power system is expressed by the following equation (1): ΔP G is the fluctuation of the power supply, ΔP L is the fluctuation of power demand, J whоle is the inertia of the system, and the reference frequency of the power system is 60 Hz.

[0007]

number

[0008] Fluctuation in power demand ΔP L is approximated by the following equation (2): k is a positive constant called the load frequency characteristic, which represents the property of the load to autonomously increase or decrease the power demand so as to offset frequency fluctuations.

[0009]

number

[0010] The origin of frequency f is set to 60Hz, and the supply and demand fluctuation ΔP G -ΔP L0 If we denote by the symbol d, we can obtain the frequency transfer function model of equation (3) from equations (1) and (2), where s is the Laplace operator.

[0011]

number

[0012] When a power plant operates in governor-free mode, the power system receives a regulation power ΔP GF is supplied. Adjustment power ΔP in governor-free operation GF can be approximated as being proportional to the frequency fluctuation Δf as shown in the following equation (4): GF is a positive proportionality coefficient.

[0013]

number

[0014] Governor-free adjustment capability ΔP GF Taking this into consideration, equation (1) becomes equation (5).

[0015]

number

[0016] When governor-free operation is taken into consideration, the supply and demand fluctuation ΔP G -ΔP L0 That is, the transfer function of the response of frequency f to d, that is, the linear approximation model with the settling state as the origin, is expressed by equation (6).

[0017]

number

[0018] Let us consider the fluctuation of frequency f from the equilibrium state when the power supply is reduced in a step (when d is changed from 0 to -1) after frequency f has stabilized. The response without governor-free operation is obtained from the transfer function in equation (3). The response with governor-free operation is obtained from the transfer function in equation (6).

[0019] To ensure stability in the face of supply-demand imbalances in the power system, it is important that the rate of change of frequency (ROCF) is small (gradual). A gradual rate of change of frequency allows other power plants to increase their supply and prevent frequency drops. Figure 11 shows the relationship between governor-free operation and the rate of change of frequency (ROCF). The dashed line represents the case with governor-free operation, and the solid line represents the case without governor-free operation. The rate of change of frequency (RoCoF) corresponds to the initial slope of the frequency step response. As shown in Figure 11, governor-free operation reduces the setpoint of the frequency step response, but governor-free operation does not change the rate of change of frequency (RoCoF).

[0020] The rate of change of frequency (RoCoF) is calculated as 1 / (4π 2 60J whоle ) is proportional to the time derivative of the frequency. Therefore, increasing the inertia is effective in reducing the rate of change of frequency (ROC0F). Specifically, as shown in equation (7), the regulation power ΔP J Demonstrate. k J is a positive proportionality coefficient. f is the time rate of change of frequency f.

[0021]

number

[0022] ΔP J ΔP GF When added to this, the supply and demand fluctuation ΔP G -ΔP L0That is, the response of frequency f to d is expressed by the following transfer function:

[0023]

number

[0024] Figure 12 shows the adjustment power ΔP J The graph shows the relationship between the frequency change rate (R0C0F) and the governor-free operation. The dashed line shows the governor-free operation only, and the regulation power ΔP J The dashed line shows the case where the proportionality coefficient k J Setting it to a positive value can make the rate of change of frequency (RoCoF) slower. [Prior art documents] [Patent documents]

[0025] [Patent Document 1] Patent Publication No. 2021-40418 Summary of the Invention [Problem to be solved by the invention]

[0026] One example of using inertia to adjust supply and demand in a power grid is a system in which the turbines of a thermal power plant that has stopped generating electricity are replaced with flywheels. In this system, the turbine that powers the generator has been removed, so it can no longer generate electricity steadily like a power plant. However, the flywheel is synchronized with the power grid via the generator, so it can continue to function as inertia.

[0027] The moment of inertia of the flywheel is J [kgm 2 ] and angular velocity is ω [rad / s], the kinetic energy K [J] of the flywheel is expressed by the following equation (9).

[0028]

number

[0029] When the rotation speed of the flywheel decreases, the flywheel provides part of its kinetic energy to the power grid. If the time rate of change of the rotation speed of the flywheel is denoted as ω·, the compensating power P [W] provided by the flywheel to the power grid is expressed by equation (10). The negative sign on the right-hand side indicates that the reduction in the kinetic energy of the flywheel produces compensating power P.

[0030]

number

[0031] The angular velocity ω of the flywheel is synchronized with the frequency of the power grid (hereinafter also referred to as "grid frequency"). The rotation speed ω of the flywheel is the synchronous speed of the grid frequency. Therefore, if the grid frequency is denoted as f and the number of poles of the generator as p, the angular velocity ω of the flywheel is expressed by equation (11).

[0032]

number

[0033] Therefore, equation (10) becomes equation (12).

[0034]

number

[0035] Since the number of poles p, the system frequency f, and the rate of change of the system frequency f· are given for a flywheel, increasing the moment of inertia J is an effective way to improve the compensating power P that the flywheel provides to the power system. However, increasing the moment of inertia J requires a larger flywheel. In cases such as installing a flywheel at a thermal power plant that has stopped generating electricity, it may be possible to install a larger flywheel. However, if one were to install a small flywheel in each home, for example, the size of the flywheel would be limited. For this reason, there is a need for technology that can improve compensating power P without increasing the moment of inertia J, so that it can be used in any facility.

[0036] An object of the present disclosure is to provide a power system stabilization device, a power system stabilization method, and a program that can provide compensation power according to fluctuations in the frequency of the power system. [Means for solving the problem]

[0037] According to one aspect of the present disclosure, a power system stabilization device includes: a frequency detector that detects a system frequency of an AC power system; a calculation unit that calculates a frequency command value that adjusts the rotation speed of a rotating machine based on the system frequency; and a power converter that is provided between the AC power system and the rotating machine and adjusts the rotation speed of the rotating machine based on the frequency command value.

[0038] According to one aspect of the present disclosure, a power system stabilization device is provided between an AC power system and an electrical equipment, and includes: a power converter that supplies AC power or DC power to the electrical equipment; a frequency detector that detects a system frequency of the AC power system; and a calculation unit that calculates a frequency command value for the AC power or a current command value for the DC power to be supplied to the electrical equipment based on the system frequency, and outputs the calculated value to the power converter.

[0039] According to one aspect of the present disclosure, a power system stabilization method includes the steps of detecting a system frequency of an AC power system, calculating a frequency command value for adjusting a rotation speed of a rotating machine based on the system frequency, and adjusting the rotation speed of the rotating machine based on the frequency command value.

[0040] According to one aspect of the present disclosure, the program causes a power system stabilization device to execute the steps of detecting a system frequency of an AC power system, calculating a frequency command value for adjusting the rotation speed of a rotating machine based on the system frequency, and adjusting the rotation speed of the rotating machine based on the frequency command value. [Effects of the Invention]

[0041] According to the above aspect, it is possible to provide compensation power according to fluctuations in the frequency of the power grid. [Brief explanation of the drawings]

[0042] [Figure 1] 1 is a diagram illustrating a functional configuration of a power system stabilizing device according to a first embodiment. [Figure 2] FIG. 6 is a diagram illustrating a functional configuration of a power system stabilizing device according to a second embodiment. [Figure 3] FIG. 6 is a diagram for explaining the function of a power system stabilizing device according to a second embodiment. [Figure 4] FIG. 10 is a diagram illustrating a functional configuration of a power system stabilizing device according to a third embodiment. [Figure 5] FIG. 10 is a diagram showing the functional configuration of an air conditioner according to a fourth embodiment. [Figure 6] FIG. 10 is a diagram illustrating a functional configuration of a control device and a power system stabilizing device according to a fourth embodiment. [Figure 7] FIG. 10 is a diagram illustrating a functional configuration of a power system stabilizing device according to a fifth embodiment. [Figure 8] FIG. 10 is a diagram showing the functional configuration of an electric furnace system and a power system stabilizing device according to a sixth embodiment. [Figure 9]FIG. 13 is a diagram illustrating a functional configuration of a battery system and a power system stabilizing device according to a modification of the sixth embodiment. [Figure 10] FIG. 1 is a schematic block diagram illustrating the configuration of a computer according to at least one embodiment. [Figure 11] FIG. 1 is a first diagram showing an example of a frequency change rate. [Figure 12] FIG. 10 is a second diagram showing an example of a frequency change rate. DETAILED DESCRIPTION OF THE INVENTION

[0043] First Embodiment The first embodiment will be described in detail below with reference to FIG. FIG. 1 is a diagram showing the functional configuration of a power system stabilizing device according to the first embodiment.

[0044] (Functional configuration of power system stabilization device) The power system stabilization device 10 according to the first embodiment is installed in a facility C such as a power plant or a factory. The power system stabilization device 10 and other electrical equipment 90 (such as a generator or electrical equipment serving as a load) in the facility C exchange power with the power system AC.

[0045] The power system stabilization device 10 includes a frequency detector 11, a calculation unit 12, a power converter 13, and a rotating machine 14. The rotating machine 14 according to the first embodiment includes an electric motor 14A and a flywheel 14B. The electric motor 14A functions as an electric motor that drives the flywheel 14B and as a generator that is driven by kinetic energy stored in the flywheel 14B. Specifically, when the supply of AC power from the power system is high (the system frequency is higher than the reference frequency), the electric motor 14A supplies electric power to the flywheel 14B to rotate it, thereby storing surplus electric power as kinetic energy in the flywheel 14B (powering the flywheel 14B). When the demand for AC power is high (the system frequency is lower than the reference frequency), the electric motor 14A functions as a generator that converts the kinetic energy stored in the flywheel 14B into electric power and outputs it (regenerates electric power from the flywheel 14B).

[0046] The frequency detector 11 detects the frequency (system frequency) of the power system AC. For example, the frequency detector 11 measures the system frequency at a connection point between the transmission line of the power system AC and the power line of the facility C. In another embodiment, the frequency detector 11 may measure the system frequency near the entrance / exit of the power converter 13 on the power system AC side.

[0047] The calculation unit 12 calculates a frequency command value for adjusting the rotation speed of the rotating machine 14 based on the system frequency, and outputs the frequency command value to the power converter 13. Specifically, the calculation unit 12 according to the first embodiment calculates the frequency command value so that the angular velocity of the flywheel 14B increases or decreases in proportion to the system frequency.

[0048] The power converter 13 is connected to the power grid AC, and adjusts the rotation speed of the rotating machine 14 based on the frequency command value calculated by the calculation unit 12, thereby consuming or supplying power to the facility C and the power grid AC to which the facility C is connected.

[0049] (Actions and effects of power system stabilizers) An AC power converter consists of an AC power regulation circuit that changes the magnitude (effective value) of the voltage without changing the frequency, and a frequency regulation circuit. Unless otherwise specified, the power converter 13 described in the first embodiment has a frequency regulation circuit and the output frequency is arbitrary.

[0050] In the case where the power converter 13 is not provided, the angular velocity ω of the electric motor 14A and the flywheel 14B is expressed by the above-mentioned formula (11), where f is the frequency of the electric power system and p is the number of poles of the electric motor 14A. In the first embodiment, when the power converter 13 is used, the angular acceleration ω of the flywheel 14B can be determined, for example, as shown in formula (13).

[0051]

number

[0052] In equation (13), k f is a control constant that adjusts the magnitude of the compensation power P, and is set to a non-negative value. f If k = 0, the compensation power P is not supplied. f The larger the positive value of ω, the larger the compensation power P. For example, when the angular velocity of the flywheel 14B is ω ref If so, the compensation power P according to the above equation (12) is expressed by equation (14).

[0053]

number

[0054] The angular velocity of the flywheel 14B is ω ref = 2πf, the control constant is k f If we set =1, then equation (14) is equal to equation (12). ref ×k f ω so that ×2 / p>1 ref or k f Increasing the value of will have the equivalent effect of increasing the inertia J.

[0055] Equation (12) expresses the compensation power generated by a flywheel synchronized with the grid frequency (a flywheel of the prior art). In a flywheel synchronized with the grid frequency, the compensation power P is determined by the moment of inertia J, the number of poles p of the motor, the grid frequency f, and its rate of change f·. Of these, the number of poles p, the grid frequency f, and its rate of change f· are given for the flywheel. Therefore, the only way to increase the compensation power P in a flywheel synchronized with the grid is to increase the moment of inertia J. In other words, the flywheel must be made larger.

[0056] On the other hand, as in the first embodiment, by using the power converter 13, the rotation of the flywheel 14B can be made independent of the system frequency. As shown in equation (14), the compensation power P is calculated based on the angular velocity ω of the flywheel 14B in addition to the moment of inertia J. ref and the control constant k f It is possible to adjust it by the product k f ×ω ref Increasing the value of θ can have the same effect as increasing the moment of inertia J. In other words, it becomes possible to provide a large compensation power P with a small flywheel.

[0057] Specific operations and effects of the power system stabilization device 10 according to the first embodiment will be described with reference to Fig. 1. The system frequency f of the power system AC is detected by a frequency detector 11. The frequency detector 11 can detect the frequency f based on the time interval at which the AC voltage waveform of the power system AC crosses 0 volts, for example.

[0058] The power converter 13 receives an AC signal with a system frequency f from the power system AC and converts it to a separately specified frequency f SV The power converter 13 outputs an AC current of frequency f SV The rotation of the flywheel 14B can be determined arbitrarily by changing the value of ω. ref If desired, the frequency of the AC output from the power converter 13 is f SV =ω ref×p / 4π. The calculation unit 12 calculates the frequency f so that the angular velocity of the flywheel 14B increases or decreases from the reference angular velocity in accordance with the fluctuation of the system frequency f (the difference from the reference frequency). SV (frequency command value) and output it to the power converter 13.

[0059] In this way, the first advantage of using the power converter 13 in the first embodiment is that the reference angular velocity of the flywheel 14B can be set arbitrarily. In addition, the response of the flywheel rotation to the fluctuation of the system frequency f is controlled by the control constant k f The second advantage is that it can be adjusted by

[0060] To reiterate, in conventional technology without a power converter, the system frequency and flywheel rotation are fixed with a proportionality coefficient of 2 / p. For example, suppose the reference frequency of the power system is 60 Hz, and the system frequency changes from 60 Hz to 60.1 Hz in one second. In this case, the compensation power P without a power converter is given by the following equation (15). To increase the compensation power P, either increase the moment of inertia J or reduce the number of poles p of the motor. However, these are often given and not optional.

[0061]

number

[0062] In contrast, the compensation power P provided by the power system stabilization device 10 according to the first embodiment is expressed by the following equation (16), where k f ×ω ref This can be done arbitrarily depending on the value of

[0063]

number

[0064] The regulating power P is proportional to the fluctuation rate f of the grid frequency. However, f is not explicitly shown in Figure 1, and the frequency command f is proportional to the frequency f. SVThe frequency command f to the power converter 13 is SV If is proportional to f, the time rate of change of the frequency command f SV · is also proportional to f·, so this is essentially the same.

[0065] In this way, the power system stabilization apparatus 10 according to the first embodiment can increase or decrease the compensation power P it provides in accordance with the system frequency. Furthermore, the power system stabilization apparatus 10 can increase the inertia of the flywheel 14B by changing the angular velocity of the flywheel 14B using the power converter 13. Therefore, the power system stabilization apparatus 10 can provide large compensation power P even when a small flywheel is used. This makes it possible to miniaturize the power system stabilization apparatus 10. While FIG. 1 shows an example in which the power system stabilization apparatus 10 is installed in a facility C such as a power generation plant or a factory, it can also be installed in facilities where a large flywheel cannot be installed, such as homes or offices.

[0066] As a modification of the first embodiment, the calculation unit 12 may calculate a frequency command value based on the angular velocity or angle of the flywheel 14B and further on estimated values ​​thereof, and adjust the AC power output by the power converter 13.

[0067] <Second embodiment> Next, the second embodiment will be described in detail with reference to Figures 2 and 3. Components common to the above-described embodiment will be given the same reference numerals and detailed description will be omitted.

[0068] (Functional configuration of power system stabilization device) FIG. 2 is a diagram showing the functional configuration of a power system stabilizing device according to the second embodiment. As shown in FIG. 2, the power system stabilizing device 10 according to the second embodiment differs from the first embodiment in that it further includes an angular velocity meter 14C that detects the angular velocity of a flywheel 14B and a compensation power limiter 15.

[0069] The compensation power limiter 15 determines the upper or lower limit of the time rate of change of the frequency command value based on the deviation between the frequency command value and the reference frequency of the power system AC.

[0070] (Actions and effects of power system stabilizers) When the power system stabilizer 10 is in a resting state, the flywheel 14B is stopped. When the power system stabilizer 10 is started, the flywheel 14B is rotated at a reference angular velocity ω ref The power system stabilization device 10 according to the second embodiment does not steadily provide the flywheel 14B with power running, but limits the power running to be provided to the flywheel 14B only when the power running provided to the flywheel 14B acts to suppress fluctuations in the system frequency of the power system AC (i.e., when the system frequency is increasing). Similarly, when the power system stabilization device 10 is stopped, the regenerative power is limited to be taken out from the flywheel 14B only when the regenerative power taken out from the flywheel 14B acts to suppress fluctuations in the system frequency of the power system AC (i.e., when the system frequency is decreasing).

[0071] For this purpose, the compensation power limiter 15 is configured to limit the reference angular velocity ω of the flywheel 14B. ref is compared with the current angular velocity ω measured by the angular velocity meter 14C, and the angular velocity ω is equal to the reference angular velocity ω ref When the power grid frequency is insufficient, regeneration is limited to 0 kW. Since the frequency of the AC power grid is a constant value, for example 60 Hz, the expected value of the rate of change of the AC power grid frequency, f·, is 0.

[0072] FIG. 3 is a diagram for explaining the function of the power system stabilizing device according to the second embodiment. As shown in FIG. 3, the angular velocity ω of the flywheel 14B is equal to its reference value ω ref When the regeneration limit value P is smaller than the angular velocity ω of the flywheel, LREG and power limit value P LPOW is "Regenerative limit value P LREG <Powering limit value P LPOW", the expected value of the compensation power P shifts to the negative side (powering the flywheel 14B and drawing power from the power grid AC). Therefore, the flywheel 14B accelerates over time. And, the reference angular velocity ω of the flywheel 14B ref The power limit value P LPOW and regeneration limit value P LREG When the flywheel 14B is set to a reference angular velocity ω ref In the area exceeding the regeneration limit value P LREG >Power limit value P LPOW ", and the expected value of the compensation power P is shifted to the positive side (power is regenerated from the flywheel 14B and released to the power grid AC). As a result, the flywheel 14B decelerates and the reference angular velocity ω ref will return to.

[0073] Figure 3 shows the regeneration limit value P LREG and power limit value P LPOW In this example, the limit values ​​are determined depending on the angular velocity ω of the flywheel 14B. SV The maximum power running value and the maximum regeneration value are mainly determined by the capacity of the power converter 13. In general, the induced voltage of the electric motor 14A is proportional to the angular velocity. Therefore, in the process of increasing the speed of the flywheel 14B, the induced voltage is proportional to the angular velocity. On the other hand, the power converter 13 has an upper limit to the current. Therefore, in the start-up process of the power system stabilization device 10, the upper limit of the output of the power converter 13 is proportional to the angular velocity. Reference angular velocity ω ref The power limit value P LPOW This is why is proportional to the angular velocity.

[0074] Specific actions and effects of the power system stabilization device 10 according to the second embodiment will be described with reference to FIG.

[0075] As shown in FIG. 2, the compensation power limiter 15 determines the power running limit value P LPOW and regeneration limit value P LREG Considering the power-limited frequency command value f SV1Determine.

[0076] The deviation between the system frequency f and a reference frequency (for example, 60 Hz) and the angular velocity ω of the flywheel 14B are input to the compensation power limiter 15. Because the reference frequency is time-invariant, the compensation power P1 when the flywheel 14B is synchronized with the power system AC can be obtained from the time change rate of the frequency deviation and the angular velocity ω of the flywheel 14B by the following equation (17).

[0077]

number

[0078] Regenerative limit value P for compensation power P1 LREG and power limit value P LPOW If the compensation power taking into consideration the above is denoted as P2, P2 is expressed by the following equation (18).

[0079]

number

[0080] The compensation power P2 is converted into a rate of change of the output frequency of the power converter 13. The converted value is f SV2 If you write ·, f SV2 · is expressed by the following equation (19).

[0081]

number

[0082] The compensation power limiter 15 integrates this to obtain the frequency command value f SV1 Ask for.

[0083]

number

[0084] In this way, the power system stabilization device 10 according to the second embodiment can suppress the disturbance of the power system AC caused by the running power when the flywheel 14B is accelerated at startup or the regenerative power when the flywheel 14B is decelerated at shutdown.

[0085] <Modification of the second embodiment> In the second embodiment, the reference angular velocity ω of the flywheel 14B is ref , and the control constant k of the compensation power P f In contrast to this, in this modification, the power system stabilization device 10 (the calculation unit 12) calculates the reference angular velocity ω of the flywheel 14B. ref , or the control constant k of the compensation power P f This embodiment differs from the second embodiment in that is variable.

[0086] (Actions and effects of power system stabilizers) The compensation power P is determined from the system frequency f of the power system AC by the above-mentioned equation (14).

[0087] The compensation power P is the regeneration limit value P LREG and the power limit value P LPOW For example, if the expected value of the square of the compensation power P satisfies the following equation (21) for an adjustment constant C that is greater than 0 and approximately equal to or less than 1, then this situation can be said to exist. A possible value for C is, for example, 0.5.

[0088]

number

[0089] The magnitude of the compensation power P is determined by the reference angular velocity ω ref and the control constant k f For example, the reference angular velocity ω can be adjusted depending on the magnitude relationship between both sides of equation (21). ref and the control constant k f If the product of these is updated at regular intervals (for example, every minute) using the following equation (22), the compensation power P can be adjusted to the regeneration limit value P LREGand power limit value P LPOW It can be kept between.

[0090]

number

[0091] In actual operation, the product of the two is the control constant k f and reference angular velocity ω ref Since the friction loss of the flywheel 14B increases with the rotation speed, the reference angular velocity ω ref To reduce the friction loss, we need to reduce the control constant k f Generally, there are upper and lower limits to the frequency change rate of the power converter 13. f is fixed to the largest possible value within the range that does not exceed the upper or lower limits of the frequency change rate, and the reference angular velocity ω ref and the control constant k f The product of these, i.e., the magnitude of the compensation power P, is ref For example, the calculation unit 12 calculates the reference angular velocity ω ref Update the value of

[0092]

number

[0093] The power converter 13 has a limit inherent to the device in terms of the power output capacity. ref , or the control constant k that determines the compensation power P f By changing the ratio of the power converter 13 to the power consumption, it is possible to increase the utilization rate of the capacity of the power converter 13. As a result, the power system stabilization device 10 can operate without the capacity of the power converter 13 being excessively over- or under-utilized.

[0094] <Third embodiment> Next, the third embodiment will be described in detail with reference to Fig. 4. Components common to the above-described embodiments are given the same reference numerals and detailed description thereof will be omitted.

[0095] (Functional configuration of power system stabilization device) FIG. 4 is a diagram showing the functional configuration of a power system stabilizing device according to the third embodiment. As shown in FIG. 4, the power system stabilizing device 10 according to the third embodiment further includes an active power detector 16 and an active power compensator 17.

[0096] The active power detector 16 detects the active power exchanged between the facility C and the power system AC. For example, the active power detector 16 measures the active power provided by the entire facility C (the power system stabilization device 10 and other electrical equipment 90) at a connection point between the transmission line of the power system AC and the power line of the facility C. In another embodiment, the active power detector 16 may measure the active power of the entire facility C at a bus or trunk line of the power distribution system of the facility C.

[0097] The active power compensator 17 calculates a correction amount for correcting the compensation power provided by the power system stabilization device 10 based on the active power of the entire facility C.

[0098] The calculation unit 12 calculates a frequency command value corrected based on the correction amount calculated by the active power compensator 17.

[0099] 4 shows an example in which an active power detector 16 and an active power compensator 17 are added to the configuration of the power system stabilization device 10 according to the first embodiment (FIG. 1), but the present invention is not limited to this. In other embodiments, the active power detector 16 and the active power compensator 17 may be added to the configuration of the power system stabilization device 10 according to the second embodiment (FIG. 2).

[0100] (Actions and effects of power system stabilizers) In the first embodiment, the frequency command value f SVis determined based on the system frequency f of the power system AC. In the third embodiment, the frequency command value f is determined based on the system frequency f of the power system AC and the active power exchanged with the power system AC. SV Determine.

[0101] The third embodiment is characterized by the active power compensator 17. In the active power compensator 17, a model of the compensation power P~ generated by the flywheel 14B for the reference model frequency f is determined as a compensation power estimation function G(f). The compensation power estimation function is, for example, the following equation (24). Note that in other embodiments, the compensation power estimation function may determine the estimated value P~ of the compensation power based on the differential value of f, the integral value of f, and further a value obtained by filtering f with a transfer function in addition to the system frequency f.

[0102]

number

[0103] In addition to the flywheel 14B, the facility C also has at least one electrical equipment 90 consuming active power. The active power P measured at the connection point between the facility C and the AC power system is whоle is the total power consumption of all the facilities C. In each of the above-described embodiments, the flywheel 14B generates compensation power based on the frequency of the AC power system, and the power consumption of other electrical equipment in the facilities C is unpredictable. In contrast, in the third embodiment, the effective power P of the entire facilities C relative to the estimated value P of the compensation power is calculated as whоle Based on the deviation of the frequency command f SV Δf SV2 The estimated compensation power P~ is corrected by, for example, the following equation (25): The direction of supplying power to the power grid AC is positive, and the active power P of the entire facility C is whоle The direction of supplying power to the AC power grid is also positive.

[0104]

number

[0105] The correction amount Δf output by the active power compensator 17 SV2 is the estimated compensation power P~, Active power P of the entire facility C whоle When the original correction amount Δf SV1 and amplifies the active power P of the entire facility C. whоle The aim is to bring the value of P~ close to the estimated value of the compensation power.

[0106] The estimated compensation power P~ is the effective power P of the entire facility C. whоle When the value of the correction amount Δf is exceeded, the active power compensator 17 outputs SV2 is the original correction amount Δf SV1 In this case, the attenuation may be limited as shown in the following equation (26).

[0107]

number

[0108] The third embodiment is effective in a facility C having a plurality of electrical equipment 90. In the facility C having a plurality of electrical equipment 90, the electrical equipment 90 other than the flywheel 14B also demands or supplies electric power, so if the electrical equipment 90 other than the flywheel 14B can also generate compensatory power in the same way as the flywheel 14B, it can contribute to adjusting supply and demand throughout the facility.

[0109] The power system stabilization device 10 according to the third embodiment determines a model G(f) of the compensation power of the flywheel 14B, and calculates the effective power P of the entire facility C. whole The frequency command value f SV By correcting this, it is possible for the entire facility to contribute to adjusting supply and demand.

[0110] <Fourth embodiment> Next, the fourth embodiment will be described in detail with reference to Figures 5 and 6. Components common to the above-described embodiments will be given the same reference numerals and detailed description will be omitted. In the fourth embodiment, an example will be described in which the power system stabilization apparatus 10 is applied to an air conditioner 20 installed in a home, an office, or the like.

[0111] (Functional configuration of air conditioner) FIG. 5 is a diagram showing the functional configuration of an air conditioner according to the fourth embodiment. As shown in FIG. 5, the air conditioner 20 includes an outdoor unit 21, an indoor unit 22, and a control device .

[0112] The outdoor unit 21 includes a compressor 210, an accumulator 211, a four-way valve 212, an outdoor blower fan 213, an outdoor heat exchanger 214, an outdoor expansion valve 215, a receiver 216, a pressure detector 217, and a variable speed drive device 218.

[0113] The compressor 210 compresses the refrigerant R circulating between the outdoor unit 21 and the indoor unit 22 to generate a high-temperature, high-pressure gaseous refrigerant.

[0114] The accumulator 211 separates the refrigerant R into a liquid state and a gas state. Of the refrigerant R separated by the accumulator 211, only the gas state refrigerant is sent to the compressor 210.

[0115] The four-way valve 212 switches the flow direction of the refrigerant R depending on the operation mode (cooling operation or heating operation) of the air conditioner 20. Fig. 5 shows an example of the state of the four-way valve 212 during cooling operation. During cooling operation, the four-way valve 212 directs the refrigerant R discharged from the compressor 210 to the outdoor heat exchanger 214, forming a refrigeration cycle S in which the refrigerant R flows in the direction indicated by the solid arrow. During heating operation, the four-way valve 212 directs the refrigerant R discharged from the compressor 210 to the indoor heat exchanger 221 of the indoor unit 22, forming a refrigeration cycle S in which the refrigerant R flows in the direction indicated by the dashed arrow.

[0116] The outdoor blower fan 213 sends outdoor air to the outdoor heat exchanger 214 .

[0117] The outdoor heat exchanger 214 exchanges heat between the refrigerant R supplied thereto and the outdoor air. The outdoor heat exchanger 214 functions as a condenser during cooling operation, and as an evaporator during heating operation.

[0118] The outdoor expansion valve 215 reduces the pressure of the refrigerant R condensed in the outdoor heat exchanger 214 during cooling operation to produce low-pressure refrigerant R.

[0119] The receiver 216 temporarily stores the liquid refrigerant R introduced therein.

[0120] The pressure detector 217 measures the pressure on the upstream side of the compressor 210 (suction pressure).

[0121] The variable speed drive device 218 supplies power of a frequency specified by the control device 23 to the compressor 210 to control the rotation speed of the compressor 210. The variable speed drive device 218 is also used as the power converter 13 of the power system stabilization device 10.

[0122] The indoor unit 22 includes an indoor blower fan 220 , an indoor heat exchanger 221 , and an indoor expansion valve 222 .

[0123] The indoor blower fan 220 sends indoor air to the indoor heat exchanger 221 .

[0124] The indoor heat exchanger 221 exchanges heat between the refrigerant R supplied therein and the indoor air. The indoor heat exchanger 221 functions as an evaporator during cooling operation, and as a condenser during heating operation.

[0125] The indoor expansion valve 222 reduces the pressure of the refrigerant R condensed in the indoor heat exchanger 221 during heating operation to produce low-pressure refrigerant R.

[0126] The control device 23 controls the operations of the outdoor unit 21 and the indoor unit 22 according to the setting conditions such as the operation mode and temperature designated by the user.

[0127] (Functional configuration of the control device) FIG. 6 is a diagram showing the functional configuration of a control device and a power system stabilizing device according to the fourth embodiment. As shown in FIG. 6, the control device 23 of the air conditioner 20 includes a target determination unit 230 and a PI controller 231.

[0128] The target determination unit 230 determines the target value P of the suction pressure of the compressor 210 of the outdoor unit 21 based on the setting conditions designated by the user. s0 Determine the target value of the suction pressure P s0 Determining the value is equivalent to determining the target value for the heating and cooling output of the air conditioner 20.

[0129] The PI controller 231 controls the target value P s0 and the current suction pressure P detected by the pressure detector 217. s Deviation ΔP s The rotation speed command value of the compressor 210 is calculated based on the above.

[0130] (Functional configuration of power system stabilization device) The functional configuration of the power system stabilization device 10 according to this embodiment will be described with reference to Fig. 6. Although Fig. 6 shows an example in which the power system stabilization device 10 is provided inside the control device 23 of the air conditioner 20, the present invention is not limited to this. In other embodiments, the power system stabilization device 10 may be provided outside the control device 23. The target value P of the suction pressure s0 is an example of a target value for the cooling / heating output of the air conditioner 20, and is not limited to this.

[0131] The power system stabilizing device 10 includes a frequency detector 11, a calculation unit 12, and a power converter 13. The function of the frequency detector 11 is the same as that of the first embodiment. Furthermore, the power system stabilizing device 10 uses the variable speed drive device 218 of the outdoor unit 21 as the power converter 13.

[0132] The calculation unit 12 calculates a frequency command value by correcting the rotation speed command value calculated by the PI controller 231 of the control device 23 in proportion to fluctuations in the system frequency f of the power system AC, and outputs the frequency command value to the power converter 13.

[0133] (Actions and effects of power system stabilizers) Here, the function and effect of the power system stabilization device 10 will be described using the refrigeration cycle S during cooling operation shown in FIG. 5 as an example.

[0134] In order to control the operation of the state of this refrigeration cycle S as intended, for example, a pressure detector 217 is provided to measure the suction pressure of the compressor 210. The cooling output of the air conditioner 20 can be approximately measured based on the suction pressure of the compressor 210. The configuration of the control device 23 shown in FIG. 6 is as follows: s The target determination unit 230 determines the suction pressure P so as to satisfy the set conditions such as the temperature set by the user. s The target value P s0 The PI controller 231 determines the target value P s0 and the detected value P of the pressure detector 217 s Deviation ΔP s When the variable speed drive device 218 of the compressor 210 is controlled based on this rotation speed command value, the cycle state of the refrigeration cycle S changes, and the suction pressure P s is the target value P s0 The target value P s0 The method for calculating the rotation speed command value is well known, and therefore the explanation will be omitted.

[0135] As described above, the variable speed drive 218 is used for the compressor 210 of the refrigeration cycle S of the air conditioner 20. When the rotation speed of the compressor 210 is changed by the variable speed drive 218, the temperature of the refrigerant discharged from the compressor 210 responds to the rotation speed without delay. However, due to the heat capacity of the room to be temperature-controlled and the heat capacities of the outdoor heat exchanger 214 and the indoor heat exchanger 221, the room temperature does not respond instantaneously to the change in the compressor rotation speed. It takes at least a few minutes for the room temperature to respond to the change in the compressor rotation speed. The power system stabilization device 10 according to the fourth embodiment utilizes this response delay to provide compensation power P.

[0136] Specifically, the calculation unit 12 extracts the difference between the system frequency f of the power system AC and its reference frequency, i.e., the high-frequency component of f-60 Hz, using the first high-pass filter 121. For example, to extract components with a period shorter than one minute, τ can be set to 2π / 60. The reason for using the first high-pass filter 121 is to limit the provision of compensation power to high-frequency components with a period shorter than one minute, for example, to avoid adversely affecting the room temperature adjustment, which is the original purpose of the air conditioner 20. The calculation unit 12 also calculates a correction amount for the rotation speed command value by performing the same calculation as in the first embodiment on the extracted high-frequency components. The calculation unit 12 adds the calculated correction amount to the rotation speed command value calculated by the PI controller 231 of the control device 23, and outputs the resulting frequency command value to the power converter 13 (the variable speed drive device 218 of the outdoor unit 21).

[0137] Moreover, the compensation power P according to the fourth embodiment is expressed by the following equation (27).

[0138]

number

[0139] In this way, the power system stabilization device 10 according to the fourth embodiment can cause the variable speed drive device 218 of the compressor 210 of the air conditioner 20 to function as a stabilizer for the power system AC. In other words, by incorporating the power system stabilization device 10 into the air conditioner 20, it is possible to add the function of suppressing (stabilizing) frequency fluctuations in the power system AC to the air conditioner 20, which is an existing electrical facility in a home or office.

[0140] 6 shows a configuration example in which the power system stabilization apparatus 10 according to the first embodiment is applied to the air conditioner 20, but the present invention is not limited to this. In other embodiments, the power system stabilization apparatus 10 according to the second or third embodiment may be applied to the air conditioner 20.

[0141] <Fifth embodiment> Next, the fifth embodiment will be described in detail with reference to Fig. 7. Components common to the above-described embodiments will be given the same reference numerals and detailed description will be omitted.

[0142] FIG. 7 is a diagram showing a functional configuration of a power system stabilizing device according to the fifth embodiment. As shown in FIG. 7, in the power system stabilization device 10 according to the fifth embodiment, the calculation unit 12 calculates the target value P s0 is corrected in proportion to the fluctuation of the system frequency f.

[0143] (Actions and effects of power system stabilizers) In the fourth embodiment, a technology was described in which the variable speed drive device of the compressor 210 of the air conditioner 20 functions as a stabilizer for the AC of the power grid. The compressor 210 of the home air conditioner 20 has a limited range of rotational speeds that it can operate in. Therefore, if positive compensation power is sustained, for example, the rotational speed of the compressor 210 will quickly reach its lower limit. The compressor 210 of the home air conditioner 20 also has a small moment of inertia, so the total amount of compensation power that can be provided before reaching the lower limit is also limited. In light of this, in the fifth embodiment, continuous compensation power can be provided by adjusting the heating or cooling capacity in addition to the rotational speed of the compressor 210.

[0144] As explained in the fourth embodiment, in a heat pump such as the refrigeration cycle S of the air conditioner 20, the heating or cooling capacity is made variable by changing the rotation speed of the compressor 210. The calculation unit 12 of the power system stabilization device 10 according to the fifth embodiment has a second high-pass filter 122 in addition to the configuration of the fourth embodiment, and further adjusts the rotation speed of the compressor 210 based on the output signal of the second high-pass filter 122. For example, the calculation unit 12 adjusts the rotation speed of the compressor 210 based on the target value P of the suction pressure input to the PI controller 231. s0 By correcting the above, the rotation speed of the compressor 210 is adjusted.

[0145] The cutoff angular velocity 1 / τ2 [rad / s] of the second high-pass filter 122 is set to be smaller than the cutoff angular velocity 1 / τ [rad / s] of the first high-pass filter 121 of the fourth embodiment, so that the rotation speed of the compressor 210 responds to fluctuations in the low frequency band of the system frequency f (i.e., continuous fluctuations). Since the power consumption of the compressor 210 is positively correlated with the rotation speed of the compressor 210, an increase in the system frequency f increases the power consumption of the compressor 210, which acts as negative compensating power P for the power system AC.

[0146] In this way, the power system stabilizing device 10 according to the fifth embodiment can continuously generate compensation power.

[0147] Sixth Embodiment Next, the sixth embodiment will be described in detail with reference to Fig. 8. Components common to the above-described embodiments are given the same reference numerals, and detailed description thereof will be omitted.

[0148] In the first to fifth embodiments, a technique has been disclosed in which the power consumed or supplied when the kinetic energy of the rotating machine (flywheel 14B, compressor 210) increases or decreases with a change in its rotation speed is used as compensation power P to stabilize the power system AC. In particular, a technique has been disclosed in which, when the frequency of the power system AC fluctuates, the rotation speed of the rotating machine is made to fluctuate more than fluctuating in synchronization with the frequency of the power system AC using power converter 13, thereby equivalently increasing the moment of inertia.

[0149] In contrast to this, in the sixth embodiment, an example will be described in which the power system stabilization device 10 is applied to electrical equipment that does not have a rotating machine.

[0150] (Functional configuration of electric furnace system) FIG. 8 is a diagram showing the functional configuration of an electric furnace system and a power system stabilizing device according to the sixth embodiment. Here, an example will be described in which the power system stabilization device 10 is applied to an electric furnace system 30. The electric furnace system 30 is one form of electrical equipment that does not have a rotating machine.

[0151] As shown in FIG. 8, the electric furnace system 30 includes a control device 31 and an electric furnace device 32.

[0152] The electric furnace device 32 includes an AC power regulator 320 , an induction winding 321 , an electric furnace 322 , and a temperature detector 323 .

[0153] The AC power regulator 320 supplies AC power to the induction winding 321. The AC power regulator 320 is also used as the power converter 13 of the power system stabilization device 10. Unlike a rotating machine, the electric furnace 322 does not need to adjust the output frequency, so the power converter 13 (AC power regulator 320) according to this embodiment does not need to have a frequency adjustment circuit. Therefore, the AC power regulator 320 is composed of only an AC power adjustment circuit such as a thyristor regulator.

[0154] When AC power is supplied to the induction winding 321, an alternating magnetic field is generated within the electric furnace 322, causing the temperature inside the electric furnace 322 to rise.

[0155] The temperature detector 323 measures the temperature inside the electric furnace 322 .

[0156] The control device 31 includes a target determination unit 310 and a PI controller 311. The target determination unit 310 determines the temperature setting value T SV The PI controller 311 determines the temperature of the electric furnace 322 when the temperature of the electric furnace 322 reaches the temperature setpoint T SV AC power regulator 320 calculates a command value for the power to be supplied to induction winding 321 so that the value approaches

[0157] (Functional configuration of power system stabilization device) The functional configuration of the power system stabilization device 10 according to this embodiment will be described with reference to Fig. 8. Note that Fig. 8 shows an example in which the power system stabilization device 10 is provided inside the control device 31 of the electric furnace system 30, but the present invention is not limited to this. In other embodiments, the power system stabilization device 10 may be provided outside the control device 31.

[0158] The power system stabilizing device 10 includes a frequency detector 11, a calculation unit 12, an active power detector 16, and an active power compensator 17. The functions of the frequency detector 11 and the active power detector 16 are the same as those in the above-described embodiments.

[0159] The active power compensator 17 calculates the active power P of the entire facility C in which a plurality of electrical equipment including the electric furnace system 30 is installed. whole The correction amount P~1 is calculated based on the above.

[0160] The calculation unit 12 calculates a frequency command value for AC power supplied from the AC power regulator 320 (power converter 13) to the induction winding 321 of the electric furnace 322, based on the correction amount P~2 corresponding to fluctuations in the system frequency of the power system AC and the correction amount P~1 calculated by the active power compensator 17. The AC power regulator 320 adjusts the AC power to be output to the induction winding 321, based on the frequency command value calculated by the calculation unit 12.

[0161] (Actions and effects of power system stabilizers) The operation and effect of the power system stabilization device 10 will be described with reference to FIG. 8. An AC power regulator 320 supplies AC power to an induction winding 321. The induction winding 321 generates an AC magnetic field in an electric furnace 322. For example, metal pieces for casting are contained in the electric furnace 322, and the metal pieces are heated to a high temperature and melted by Joule heating due to eddy currents induced in the metal pieces by the AC magnetic field and their own electrical resistance. The temperature T PV is measured by a temperature detector 323. The temperature in the electric furnace 322 is set to a set value T SV The AC power regulator 320 is configured such that, for example, the PI controller 311 sets a set value T SV and the temperature T in the electric furnace 322 PV The AC power supplied to the induction winding 321 is adjusted in accordance with a command value calculated based on the deviation of the input voltage Vcc.

[0162] In the first to fifth embodiments, examples have been described in which electrical equipment having a rotating machine is used. When a rotating machine is used, if the rotation speed of the rotating machine is adjusted in proportion to the frequency fluctuation of the power grid AC, the kinetic energy consumed or supplied by the rotating machine becomes the compensation power P in proportion to the time rate of change of the rotation speed of the rotating machine increasing or decreasing. However, for example, the electric furnace 322 does not have anything equivalent to rotational energy, so it consumes power proportional to the time rate of change f· of the frequency of the power grid AC and uses that as a substitute. Specifically, the calculation unit 12 calculates an estimated value of the compensation power P using the compensation power model G in Fig. 8. The value is P~1. The active power compensator 17 calculates the active power P, for example, that the entire facility C exchanges with the power grid AC. whole Enter the active power P whole The active power compensator 17 supplies the compensating power P to the AC power grid in a positive direction, similar to the compensating power P. whole is filtered by a third high-pass filter 171 to obtain P whole Extract the fluctuation component of P whole and outputs a correction amount P~2 based on the deviation between the fluctuation component of the compensation power model G and the compensation power model G. The calculation unit 12 subtracts the sum of the estimated value P~1 of the compensation power and the correction amount P~2 from the output of the PI controller 311 for temperature control to calculate a frequency command value for the AC power regulator 320.

[0163] The second high-pass filter 122 is for generating compensation power for continuous deviations in the system frequency of the power system AC, as in the fifth embodiment.

[0164] In this way, the power system stabilization device 10 according to the sixth embodiment can provide compensation power P according to frequency fluctuations of the power system AC by using electrical equipment that does not have a rotating machine (for example, an electric furnace 322).

[0165] <Modification of the Sixth Embodiment> In the sixth embodiment, an example in which the power system stabilization device 10 is applied to the electric furnace system 30 has been described, but the present invention is not limited to this. As in this modification, the power system stabilization device 10 may be applied to a storage battery system 40. The electric furnace system 30 is a form of electrical equipment that does not have a rotating machine.

[0166] (Functional configuration of the battery storage system) FIG. 9 is a diagram illustrating a functional configuration of a battery system and a power system stabilizing device according to a modification of the sixth embodiment. As shown in FIG. 9, a storage battery system 40 includes a control device 41 and a storage battery device 42.

[0167] The storage battery device 42 includes a converter 420 , a storage battery 421 , and a current detector 422 .

[0168] The rectifier 420 is, for example, a rectifier. The rectifier 420 converts AC power into DC power and supplies it to the storage battery 421. The rectifier 420 is also used as the power converter 13 of the power system stabilization device 10.

[0169] The storage battery 421 stores the DC power supplied from the rectifier 420 .

[0170] The current detector 422 detects the current I PV Measure.

[0171] (Actions and effects of power system stabilizers) The operation and effect of the power system stabilization device 10 will be described with reference to FIG. 9. FIG. 9 shows a control system in a current control mode in the early stage of charging. In the early stage of charging, the voltage of the storage battery 421 is low, so current control is performed to prevent the storage battery 421 from being damaged by an overcurrent. A target determination unit 410 of the control device 41 determines a current setting value I SV The forward converter 420 (power converter 13) is configured to, for example, calculate a current I detected by a current detector 422 using a set value ISV set by a PI controller 411. PVThe DC current supplied to the storage battery 421 is adjusted in accordance with a command value calculated based on the deviation from the reference value.

[0172] As in the sixth embodiment, the active power compensator 17 of the power system stabilization device 10 calculates the active power P whole and outputs a correction amount P~2 based on the deviation between the fluctuation component of the power system frequency and the compensation power model G. The calculation unit 12 inputs the deviation of the system frequency to the compensation power model G to calculate an estimated value P~1 of the compensation power. The calculation unit 12 also subtracts the sum of the estimated value P~1 of the compensation power and the correction amount P~2 from the output of the PI controller 411 to calculate a current command value to be output to the forward converter 420.

[0173] In this way, the power system stabilizing device 10 according to this modification can use the storage battery 421 to provide compensation power P according to frequency fluctuations in the power system AC.

[0174] <Computer configuration> FIG. 10 is a schematic block diagram illustrating the configuration of a computer according to at least one embodiment. As shown in FIG. 10, a computer 90 includes a processor 91, a main memory 92, a storage 93, and an interface 94.

[0175] The above-described power system stabilization device 10, the control device 23 of the air conditioner 20, the control device 31 of the electric furnace system 30, and the control device 41 of the storage battery system 40 are each implemented in a computer 90. The operations of each of the above-described processing units are stored in the form of a program in a storage 93. The processor 91 reads the program from the storage 93, loads it into a main memory 92, and executes the above-described processing in accordance with the program. The processor 91 also allocates storage areas in the main memory 92 corresponding to each of the above-described storage units in accordance with the program.

[0176] The program may be for realizing some of the functions to be performed by the computer 90. For example, the program may be combined with other programs already stored in storage or other programs implemented in other devices to perform the functions. In other embodiments, the computer may include a custom LSI (Large Scale Integrated Circuit) such as a PLD (Programmable Logic Device) in addition to or instead of the above configuration. Examples of PLDs include PAL (Programmable Array Logic), GAL (Generic Array Logic), CPLD (Complex Programmable Logic Device), and FPGA (Field Programmable Gate Array). In this case, some or all of the functions realized by the processor may be realized by the integrated circuit.

[0177] Examples of storage 93 include a hard disk drive (HDD), a solid state drive (SSD), a magnetic disk, a magneto-optical disk, a compact disc read-only memory (CD-ROM), a digital versatile disc read-only memory (DVD-ROM), and a semiconductor memory. Storage 93 may be an internal medium directly connected to the bus of computer 90, or an external medium connected to computer 90 via interface 94 or a communication line. Furthermore, when this program is distributed to computer 90 via a communication line, computer 90 that receives the program may load the program into main memory 92 and execute the above-described processing. In at least one embodiment, storage 93 is a non-transitory tangible storage medium.

[0178] As described above, several embodiments according to the present disclosure have been described, but all of these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope of the invention and its equivalents as defined in the claims, as well as in the scope and spirit of the invention.

[0179] <Additional Notes> The above-described embodiments can be understood, for example, as follows.

[0180] (1) According to a first aspect of the present disclosure, a power system stabilization device 10 includes a frequency detector 11 that detects a system frequency of an AC power system AC, a calculation unit 12 that calculates a frequency command value that adjusts the rotation speed of a rotating machine 14, 210 based on the system frequency, and a power converter 13 that is provided between the AC power system and the rotating machine 14, 210 and adjusts the rotation speed of the rotating machine 14, 210 based on the frequency command value.

[0181] In this way, the power system stabilizing device 10 can provide compensation power P according to the system frequency.

[0182] (2) According to a second aspect of the present disclosure, in the power system stabilizing device 10 according to the first aspect, the rotating machine 14 has a flywheel 14B and an electric motor 14A that functions as an electric motor for driving the flywheel 14B and as a generator driven by kinetic energy accumulated in the flywheel 14B, and the calculation unit 12 calculates a frequency command value so that the angular velocity of the flywheel 14B increases or decreases in proportion to the system frequency.

[0183] In this way, the power system stabilization device 10 can increase the inertia of the flywheel 14B by changing the angular velocity of the flywheel 14B using the power converter 13. Therefore, the power system stabilization device 10 can provide a large compensation power P even if a small flywheel is used. This makes it possible to make the power system stabilization device 10 smaller, and it can be applied to facilities such as homes and offices where there is no space to install a large device.

[0184] (3) According to a third aspect of the present disclosure, the power system stabilizing device 10 according to the second aspect further includes a compensation power limiter 15 that determines an upper or lower limit of the time rate of change of the frequency command value based on the deviation between the frequency command value and the reference frequency of the alternating current power system AC.

[0185] In this way, the power system stabilization device 10 can suppress the power running power when accelerating the flywheel 14B at startup or the regenerative power when decelerating the flywheel 14B at shutdown from becoming a disturbance in the power system AC.

[0186] (4) According to a fourth aspect of the present disclosure, in the power system stabilizing device 10 according to the second or third aspect, the calculation unit 12 calculates the reference angular velocity ω of the flywheel 14B. ref or the control constant k that determines the compensation power f is determined based on the magnitude of the rate of change of the frequency command value.

[0187] In this way, the power system stabilization device 10 can increase the utilization rate of the capacity of the power converter 13. As a result, the power system stabilization device 10 can operate without the capacity of the power converter 13 being excessively over- or under-utilized.

[0188] (5) According to a fifth aspect of the present disclosure, in the power system stabilization device 10 according to the first aspect, the rotating machine is the compressor 210 of the air conditioner 20, and the calculation unit 12 calculates a frequency command value obtained by correcting the rotation speed command value output by the control device 23 of the air conditioner 20 in proportion to fluctuations in the system frequency.

[0189] In this way, the power system stabilization device 10 can cause the variable speed drive device 218 of the compressor 210 of the air conditioner 20 to function as a stabilizer for the power system AC. In other words, by incorporating the power system stabilization device 10 into the air conditioner 20, it is possible to add the function of suppressing (stabilizing) frequency fluctuations in the power system AC to the air conditioner 20, which is an existing electrical facility in a home or office.

[0190] (6) According to a sixth aspect of the present disclosure, in the power system stabilization device 10 according to the fifth aspect, the calculation unit 12 calculates the target value P of the output of the air conditioner 20 used to calculate the rotation speed command value. s0 is further corrected in proportion to the fluctuation of the grid frequency.

[0191] In this way, the power system stabilizing device 10 can continuously provide compensation power.

[0192] (7) According to a seventh aspect of the present disclosure, the power system stabilizing device 10 according to any one of the first to sixth aspects further includes, in a facility C having the power system stabilizing device 10 and the electrical equipment 90, an active power detector 16 that detects active power exchanged between the entire facility C and the AC power system AC, and an active power compensator 17 that calculates a correction amount for a frequency command value based on the active power, and the calculation unit 12 calculates a frequency command value based on the system frequency of the AC power system AC and the correction amount.

[0193] In this way, the power system stabilization device 10 can contribute to the adjustment of supply and demand for the entire facility.

[0194] (8) According to an eighth aspect of the present disclosure, a power system stabilization device 10 is provided between an alternating current power system AC and electrical equipment 30, 40, and includes a power converter 13 that supplies AC power or DC power to the electrical equipment 30, 40, a frequency detector 11 that detects a system frequency of the alternating current power system AC, and a calculation unit 12 that calculates a frequency command value for AC power or a current command value for DC power to be supplied to the electrical equipment 30, 40 based on the system frequency, and outputs the calculated value to the power converter 13.

[0195] In this way, the power system stabilization device 10 can provide compensation power P according to frequency fluctuations of the power system AC by using electrical equipment that does not have a rotating machine (for example, an electric furnace 322, a storage battery 421).

[0196] (9) According to a ninth aspect of the present disclosure, a power system stabilization method includes the steps of detecting a system frequency of an alternating current power system AC, calculating a frequency command value for adjusting the rotation speed of the rotating machine 14, 210 based on the system frequency, and adjusting the rotation speed of the rotating machine 14, 210 based on the frequency command value.

[0197] (10) According to a tenth aspect of the present disclosure, the program causes the power system stabilization device to perform the steps of detecting a system frequency of an alternating current power system AC, calculating a frequency command value for adjusting the rotation speed of the rotating machine 14, 210 based on the system frequency, and adjusting the rotation speed of the rotating machine based on the frequency command value. [Explanation of symbols]

[0198] 10 Power system stabilizer 11 Frequency Detector 12 Arithmetic section 121 First high-pass filter 122 Second high-pass filter 13 Power Converter 14 Rotating Machinery 14A electric motor 14B flywheel 14C angular velocity meter 15 Compensation Power Limiter 16 Active Power Detector 17 Active Power Compensator 171 Third High-Pass Filter 20 Air conditioner 21 Outdoor unit 210 Compressor (rotating machine) 217 Pressure detector 218 Variable Speed ​​Drive (Power Converter) 22 Indoor unit 23 Control device 230 Goal Setting Department 231 PI Controller 30 Electric furnace system (electrical equipment) 31 Control device 310 Goal Setting Department 311 PI Controller 32 Electric furnace equipment 320 AC power regulator (power converter) 321 Inductive Winding 322 Electric furnace 323 Temperature Sensor 40 Battery storage system (electrical equipment) 41 Control device 410 Goal Setting Department 411 PI Controller 42 Battery equipment 420 Forward converter (power converter) 421 Storage battery 422 Current Detector

Claims

1. a frequency detector for detecting a system frequency of an AC power system; a calculation unit that calculates a frequency command value that adjusts the rotation speed of a rotary machine based on the system frequency; a power converter that is provided between the AC power system and the rotary machine and that adjusts the rotation speed of the rotary machine based on the frequency command value; Equipped with the rotary machine is a compressor of an air conditioner, The calculation unit calculates a frequency command value obtained by correcting a rotation speed command value output by a control device of the air conditioner in proportion to fluctuations in the system frequency. Power system stabilizer.

2. The calculation unit further corrects the target value of the output of the air conditioner used in calculating the rotation speed command value in proportion to fluctuations in the system frequency. The power system stabilization device according to claim 1 .

3. an active power detector in a facility having the power system stabilization device and electrical equipment, which detects active power exchanged between the entire facility and the AC power system; an active power compensator that calculates a correction amount for the frequency command value based on the active power; Furthermore, the calculation unit calculates the frequency command value based on the system frequency of the AC power system and the correction amount. The power system stabilization device according to claim 1 or 2.

4. a power converter provided between an AC power system and an electrical equipment to supply AC power or DC power to the electrical equipment; a frequency detector for detecting a system frequency of the AC power system; a calculation unit that calculates a frequency command value of the AC power or a current command value of the DC power to be supplied to the electrical equipment based on the system frequency, and outputs the calculated value to the power converter; A power system stabilizer comprising:

5. Detecting a system frequency of an AC power system; calculating a frequency command value for adjusting the rotation speed of a rotary machine based on the system frequency; a frequency command value provided between the AC power system and the rotary machine, and adjusting a rotation speed of the rotary machine based on the frequency command value; and the rotary machine is a compressor of an air conditioner, The step of calculating the frequency command value includes calculating the frequency command value by correcting a rotation speed command value output by the control device of the air conditioner in proportion to fluctuations in the system frequency. Power system stabilization method.

6. Detecting a system frequency of an AC power system; calculating a frequency command value for adjusting the rotation speed of a rotary machine based on the system frequency; a frequency command value provided between the AC power system and the rotary machine, and adjusting a rotation speed of the rotary machine based on the frequency command value; A program for causing a power system stabilization device to execute the above, the rotary machine is a compressor of an air conditioner, The step of calculating the frequency command value includes calculating the frequency command value by correcting a rotation speed command value output by the control device of the air conditioner in proportion to fluctuations in the system frequency. program.

Images