JP4432938B2 - Power stabilization system using power storage device and control device thereof - Google Patents

Description

  The present invention relates to a power stabilization system using a power storage device.

  In an electric power system, frequency fluctuations occur when the balance between generated power and consumed power is lost. Therefore, the power company adjusts the output increase / decrease of the generator so as to always balance the power consumption and the generated power which change every moment by various frequency control according to the fluctuation period of the load. Minor fluctuations of several minutes or less can be dealt with instantaneously by governor-free control of the generator speed. Short cycle fluctuations of several minutes to several tens of minutes can be dealt with by controlling the generator output with LFC (load frequency control) of the power supply system, but the response speed is slightly slower than governor-free control. For long-period fluctuations of several tens of minutes or more, EDC (Economic Load Allocation Control) performs load distribution considering the economics of the generator, and the fluctuation range that can be handled is large, but the response speed is slow There is.

  On the other hand, in recent years, interconnection to a power system of a distributed power source using natural energy such as wind power and sunlight has increased. However, since the output of a distributed power source that uses natural energy fluctuates from moment to moment depending on natural conditions such as wind speed, system frequency and voltage fluctuations occur especially in weak power systems such as remote areas and remote islands. It may become.

  For example, in a wind power generation facility, when the wind speed exceeds the cutoff wind speed, the rotation is stopped for wind turbine protection, and the output of the wind power generator may change greatly from the maximum output to zero output. When such an excessive and sudden power fluctuation occurs, the EDC cannot keep up with the control (the EDC has a large fluctuation range, but the response speed is slow, so it can only deal with slow fluctuations). The power fluctuation that cannot be done will be handled by LFC and governor-free. However, since LFC and governor-free have a small frequency adjustment capacity, there is a concern that it may be difficult to keep the frequency within the system operation target value.

  Therefore, a system has been developed that compensates for power fluctuations such as output fluctuations, load fluctuations, power fluctuations, etc., by absorbing or discharging power using a power storage device such as a flywheel or a secondary battery. Yes. For example, when compensating for fluctuations in the output of a wind power generator, if the power output of the wind power generator increases, the power output of the power storage device decreases or power absorption increases, and the power output of the wind power generator decreases. In some cases, power fluctuations at the interconnection point between the wind power generator and the power storage device can be compensated by reducing the power absorption of the power storage device or increasing the power release.

  However, the capacity of the power storage device is finite, and there is an allowable operating range. For this reason, deviating from the allowable operating range leads to, for example, a reduction in battery life due to overcharge / overdischarge in a secondary battery, and an operation instability due to an overspeed in a flywheel or an insufficient rotation speed in a flywheel. Further, when the power storage amount reaches the upper limit or the lower limit, no more power compensation can be performed. In view of this, various methods relating to power storage amount management / control of the power storage device have been proposed in order to protect and extend the life of the device.

As an example of using a secondary battery as a power storage device, Patent Document 1 and as an example of using a flywheel include Patent Document 2 and the like.
In Patent Document 1, a secondary battery control device detects a terminal voltage (corresponding to a power storage amount) of a secondary battery, and variably controls a limiter of a compensation command value according to the terminal voltage. As the terminal voltage increases (the amount of stored power increases), the limiter in the discharge direction increases and the limiter in the charge direction decreases. Conversely, the limiter is set as the terminal voltage decreases (the amount of stored power decreases). This realizes prevention of overcharge / overdischarge of the secondary battery.

In Patent Document 2, the flywheel control device has an active power control loop and a speed control loop, and variably controls the gain of each control loop. When the rotational speed of the flywheel (equivalent to the amount of stored power) is within a predetermined stable range, the active power is matched with the target value by increasing the gain of the active power control loop, and the rotational speed of the flywheel is within the predetermined stable range. When the upper limit or lower limit is exceeded, the gain of the speed control loop is increased to prevent overspeed or stall of the flywheel, thereby realizing stable operation.
JP 2001-298772 A JP 2004-260929 A

  In Patent Document 1, when an excessive and rapid power fluctuation occurs, the terminal voltage of the secondary battery increases (or decreases), and finally the compensation amount is limited by the variable limiter. Thus, the deviation of the allowable operating range can be prevented, but there is a problem that compensation for power fluctuation cannot be made while the compensation amount is limited by the variable limiter. From another point of view, if an attempt is made to compensate for excessive and rapid power fluctuations, a large-capacity power storage device is required, resulting in an increase in installation cost and maintenance cost.

  In Patent Document 2, when an excessive and rapid power fluctuation occurs, the rotational speed of the flywheel exceeds the upper limit or lower limit of a predetermined stable range. At this time, the active power control loop gain can be reduced to prevent the deviation from the allowable operating range, but the speed control loop gain can be increased to obtain the power fluctuation compensation amount necessary for power fluctuation. On the contrary, there was a possibility of increasing the power fluctuation. In addition, there is a problem that the power compensation operation is not performed at all when the gain of the active power control loop becomes zero. Similarly to the above, if an attempt is made to compensate for an excessive and rapid power fluctuation, a large-capacity power storage device is required, and there is a problem that the installation cost and the maintenance cost increase.

  Thus, even if the conventional technology can prevent the power storage device from deviating from the allowable operating range, it cannot be said that efficient and effective power fluctuation compensation is realized within the allowable operating range. When compensating for power fluctuations, a large-capacity power storage device is required.

  This is a case where the capacity of the power storage device is not sufficient with respect to the compensation point power fluctuation amount, and the deviation of the allowable operating range becomes a problem, especially ideal for effectively suppressing excessive and rapid power fluctuations. The power compensation operation is as follows.

-Continue stable operation within the allowable operating range of the power storage device.
• Ensure the necessary amount of compensation for short-cycle power fluctuations (especially fluctuations in the governor-free and LFC areas where the frequency adjustment capacity is small).

  • To suppress excessive and sudden power fluctuations, the fluctuations are suppressed to a level that can be handled by system frequency control. That is, power fluctuations that can be handled by frequency control on the system side (especially slow fluctuations in the EDC region where the frequency adjustment capacity is large) are allowed.

  An object of the present invention is to realize the power compensation operation as described above, and to use the power storage device that can efficiently and effectively suppress an excessive and rapid power fluctuation with a small capacity power storage device. It is to provide a stabilization system, its control device and the like.

  A power stabilization system using a power storage device according to the present invention is a power stabilization system that suppresses fluctuations in active power of an AC power system, and stores power and absorbs power of the AC power system or the AC power. A power storage device that discharges power to the grid, and bidirectional power that mutually converts input / output of power accompanying absorption / release of stored power of the power storage device between the AC power system and the power storage device The control device comprises: a converter; and a control device that suppresses the active power fluctuation of the AC power system by controlling the conversion operation of the bidirectional power converter according to the active power fluctuation of the AC power system. Is an active power fluctuation component extraction filter that extracts an active power fluctuation component in a predetermined frequency region according to a set filter time constant from the active power of the AC power system; Power fluctuation compensation amount adjusting means for controlling the conversion operation of the bidirectional power converter according to the power fluctuation compensation amount according to the magnitude of the active power fluctuation component, and the active power fluctuation component are input, and the active power fluctuation component Filter time constant setting means for setting the filter time constant of the active power fluctuation component extraction filter based on the magnitude of the absolute value, the filter time constant setting means having an absolute value of the active power fluctuation component When the frequency is small, the filter time constant is set so that the frequency region in the active power fluctuation component extraction filter is narrowed so that the low frequency region to be cut in the filter is widened, and the absolute value of the active power fluctuation component is When it becomes larger, the filter time constant is set so that the frequency region in the active power fluctuation component extraction filter becomes wider. So that the low frequency range is narrowed to cut in the filter by a constant.

  According to the power stabilization system using the power storage device configured as described above, the compensation frequency region should be kept to the minimum necessary (only for short-period power fluctuations) while the absolute value of the active power fluctuation component is small. Thus, it is possible to secure a sufficient compensation margin in preparation for excessive and rapid power fluctuations (particularly excessive and rapid fluctuations that cannot be followed by EDC control and affect the frequency adjustment capacity). And when the absolute value of the active power fluctuation component becomes large, that is, for excessive and sudden power fluctuation, it is secured by expanding the compensation frequency range from short cycle power fluctuation to long cycle power fluctuation. Maximum compensation can be performed using the compensation margin.

In this way, it is possible to efficiently and effectively operate the power storage device that is optimal for suppressing excessive and rapid power fluctuations with a power storage device having a small capacity.
The filter time constant to be set has a lower limit value. This lower limit value is a value that enables extraction of at least short-period power fluctuations in the frequency region. As a result, for short-period power fluctuations (particularly, fluctuations in the governor-free area and LFC area where the frequency adjustment capacity is small), it is always within the compensation frequency area, so that the necessary compensation amount can be ensured.

  According to the power stabilization system using the power storage device of the present invention, its control device, etc., it is possible to efficiently and effectively compensate for power fluctuations to an excessive and rapid power fluctuation with a power storage device having a small capacity. Is possible.

Embodiments of the present invention will be described below with reference to the drawings.
The present invention relates to a power stabilization system that suppresses fluctuations in the active power of an AC power system. In the following description, an AC power system to which a distributed power source using the natural energy is connected is taken as an example. However, it is not limited to this example. The power stabilization system of the present invention can be applied as long as it is intended to suppress fluctuations in the active power of the AC power system, such as load fluctuations and interconnection point power fluctuations during microgrid interconnection operation. In the following description, a wind power generator will be described as an example of the distributed power source using the natural energy. However, the present invention is not limited to this example, and may be solar power generation, for example.

FIG. 1 is a configuration diagram of a power stabilization system using a power storage device according to the present embodiment.
The illustrated power stabilization system includes a power storage device 1, a bidirectional power converter 2, and a control device 10, and is connected to a power system 6 via a transformer 3.

The power storage device 1 is, for example, a flywheel, a secondary battery, a capacitor, or the like.
The bidirectional power converter 2 is connected to the power system 6 based on the power fluctuation compensation signal PO from the control device 10 (here, the direction in which the power is discharged from the power storage device 1 is “positive”). Power is exchanged with the device 1. When the power storage device 1 is a flywheel, the AC power on the flywheel side and the AC power on the power system 6 side are converted bidirectionally, and when the power storage device 1 is a secondary battery, a capacitor, or the like, The DC power on the secondary battery / capacitor side and the AC power on the power system 6 side are converted bidirectionally.

Here, it is assumed that the output fluctuation compensation of the distributed power source using natural energy is performed, and the wind power generator 4 is connected to the power system 6 via the transformer 5. (As described above, by detecting the effective power at the microgrid interconnection point in FIG. 1, it can also be applied to the suppression of fluctuations in the interconnection point power flow, etc.)
The control device 10 includes an operating temperature detector 11, a power storage amount detector 12, a power fluctuation compensation amount adjustment unit 13, an active power detector 14, an active power fluctuation component extraction filter 15, a filter time constant setting unit 16, and a phase adjustment. Part 17 and the like.

  Although not particularly shown, the control device 10 includes a CPU and the like, a storage device such as a memory and various storage media (such as a hard disk), and the like, and includes the power fluctuation compensation amount adjusting unit 13, the active power fluctuation component extraction filter 15, Processing (to be described later) by the filter time constant setting unit 16 and the phase adjustment unit 17 may be realized by hardware, or by a CPU reading and executing a predetermined application program stored in the storage device. May be. Further, when realized by hardware, it may be controlled using a digital control device (programmable controller), or may be realized by an analog control circuit such as an operational amplifier.

The active power detector 14 detects the wind power generator active power PG based on the voltage / current value at the output end of the wind power generator 4.
The active power fluctuation component extraction filter 15 extracts the active power fluctuation component signal ΔPG in the compensation frequency domain from the wind power generator active power PG by a filter that extracts fluctuations such as a high-pass filter (in other words, other than the compensation frequency domain). The frequency domain fluctuation component is removed (cut). The compensation frequency region is determined by a filter time constant such as the high-pass filter, and normally the filter time constant is set so as to extract only a short-cycle power fluctuation, but when there is an excessive and rapid power fluctuation described later, A filter time constant is set so as to extract long-period fluctuations. The setting of the filter time constant is performed by the filter time constant setting unit 16 as needed.

  The active power fluctuation component extraction filter 15 may use any number of high-pass filters or may have a configuration in which several high-pass filters are connected in series as long as the active power fluctuation component extraction filter 15 has a function of extracting an active power fluctuation component. . Alternatively, a filter that removes fluctuations such as a low-pass filter (any number of low-pass filters may be used as long as it has a function of removing active power fluctuation components, or a configuration in which several stages of low-pass filters are connected in series. Or the compensation target value PA is calculated by removing the active power fluctuation component from the wind power generator active power PG by smoothing processing such as moving average, and the compensation target value PA is further calculated from the active power measurement value PG. The compensation power ΔPG may be calculated by subtraction.

  The filter time constant setting unit 16 determines the filter time constant command value TO according to the upper limit value / lower limit value of the predetermined filter time constant and the active power fluctuation component signal ΔPG, and this filter time constant command value The filter time constant of the active power fluctuation component extraction filter 15 is set using TO.

Details of the configuration and principle of the filter time constant setting unit 16 will be described later.
The phase adjustment unit 17 is composed of an advance / delay filter, a gain, etc., adjusts the phase in consideration of the delay of the control system, etc., and sets the gain to -1.0 (to make the discharge direction positive). Is inverted to generate a control signal that is a source of the power fluctuation compensation signal PO.

  The power storage amount detector 12 detects / calculates the power storage amount ES of the power storage device 1 directly or indirectly. For example, when the power storage device 1 is a flywheel, the rotational speed of the flywheel is detected. When the power storage device 1 is a secondary battery, a capacitor, or the like, the terminal voltage is detected, and the power storage amount ES is calculated based on the detection result. To do.

The operating temperature detector 11 detects / calculates the operating temperature TS of the power storage device 1 directly or indirectly.
In addition, when it is simply described as “detect” regarding the power storage amount or the operating temperature, “directly or indirectly detected / calculated” (directly detected or indirectly detected by performing a calculation process) ).

  The power fluctuation compensation amount adjustment unit 13 includes a gain, a variable limiter, and the like, and basically generates a power fluctuation compensation amount PO that is a command value to the bidirectional converter according to the magnitude of the active power fluctuation component. However, if the power storage device is likely to deviate from the allowable operating range (upper and lower limits of the stored power ES and operating temperature TS), the stored power will depend on the detection signal such as the stored power ES or operating temperature TS. The power fluctuation compensation amount PO is adjusted / restricted so that the ES or the operating temperature TS does not exceed the allowable operating range.

  For example, when the power storage amount ES reaches the upper limit value (maximum power storage amount), the lower limit value of the variable limiter is set to zero to prevent the power storage device 1 from absorbing power. On the other hand, when the power storage amount ES reaches the lower limit value (the minimum power storage amount), the upper limit value of the variable limiter is set to zero, thereby preventing the power storage device 1 from discharging power. As for the control of the variable limiter between the upper and lower limits of the power storage amount ES, the compensation signal in the power absorption direction is increased by decreasing the lower limit value of the variable limiter and increasing the upper limit value when the power storage amount ES is large. It is possible to suppress the suppression of the compensation signal in the power discharge direction. Conversely, when the power storage amount ES is small, increasing the lower limit value of the variable limiter and decreasing the upper limit value greatly suppresses the compensation signal in the power discharge direction and reduces the suppression of the compensation signal in the power absorption direction. it can. The control characteristics of the power fluctuation compensation amount adjusting unit 13 are adjusted in consideration of the type and characteristics of the power storage device 1, the control characteristics of the filter time constant setting unit 16, and the like.

  The characteristic of the control device 10 configured as described above is the filter time constant setting unit 16. In FIG. 1, the configuration other than the filter time constant setting unit 16 is substantially the same as that of the conventional technique. That is, for example, in Patent Document 2, the active power fluctuation component extraction filter 15 corresponds to a collection of “active power target value calculation (32a)” and “subtracter (32b)”. Similarly, the phase adjustment unit 17 corresponds to a “phase compensation circuit (32d)”. The power fluctuation compensation amount adjustment unit 13 includes a “gain (32c)”, an “active power limiter (32f)”, a “speed control loop (34)” that generates a correction signal, and a “subtracter (32e)”. It corresponds to the summarized part, and it generates power fluctuation compensation amount that is a command value to bidirectional converter according to the size of active power fluctuation component, and power fluctuation so that power storage amount does not exceed allowable operating range It can be said that this is the part that controls the magnitude of the compensation signal.

Therefore, the configuration other than the filter time constant setting unit 16 is basically only described above, and will not be described in further detail.
Hereinafter, the configuration and operation of the filter time constant setting unit 16 will be described in detail.

A configuration example of the active power fluctuation component extraction filter 15 and the filter time constant setting unit 16 is shown in FIG. In this example, a configuration example of the filter time constant setting unit 16 corresponding to the case where the active power fluctuation component extraction filter 15 (high-pass filter) has the illustrated configuration (sT0 / (1 + sT0)) is shown. This is merely an example, and other configurations may be used. That is, any configuration that satisfies the following conditions is acceptable.
-Input signal absolute value | X | is large ⇒ Filter time constant command value TO is large
⇒ The compensation frequency region becomes wider (the low frequency region to be cut becomes narrower).
-Input signal absolute value | X | is small ⇒ Filter time constant command value TO is small
⇒ The compensation frequency region becomes narrower (the low frequency region to be cut becomes wider).

<Meaning / operation / setting method of each block>
The active power fluctuation component signal ΔPG, which is an input signal, enters the absolute value calculator 21 and the absolute value | ΔPG | of the active power fluctuation component signal ΔPG is calculated. The active power fluctuation component signal absolute value | ΔPG | enters the control gain unit 22, is adjusted in magnitude by the control gain K (K> 0), and becomes a filter control signal. Then, the filter time constant command value TO is generated and output by limiting the lower limit value Tmin of the filter control signal by the filter time constant lower limiter 24. Based on the filter time constant command value TO that is the output of the filter time constant setting unit 16, the filter time constant TO of the active power fluctuation component extraction filter 15 is set. This basically sets the command value TO as a new filter time constant TO.

In FIG. 2, it may seem that only the denominator TO shown in the active power fluctuation component extraction filter 15 is set, but naturally both TO of the numerator and denominator are set.
Thereby, when the absolute value | ΔPG | of the active power fluctuation component signal ΔPG is small, the filter time constant command value TO becomes the lower limit value Tmin in the filter time constant lower limiter 24, and in this state, only the short cycle fluctuation component is present. Within the compensation frequency region.

  Note that the lower limit value Tmin in the filter time constant lower limiter 24 is determined so that the compensation frequency region becomes a necessary minimum. This is determined by the grid interconnection discussion and the specifications of the power stabilization system, and if the fluctuation period of a short period (for example, 20 minutes or less (0.0008 Hz or more)) is necessarily compensated, the lower limit in the filter time constant lower limiter 24 The value Tmin is about 191 seconds.

  When the absolute value | ΔPG | of the active power fluctuation component signal ΔPG increases and the filter control signal output from the control gain unit 22 becomes greater than the lower limit value Tmin in the filter time constant lower limiter 24, the filter time constant command value TO increases, and the high-pass filter time constant of the active power fluctuation component extraction filter 15 (time constant TO of the high-pass filter) increases. As a result, the low frequency region to be cut in the active power fluctuation component extraction filter 15 is narrowed (that is, the lower frequency component is extracted), and the compensation frequency region is from the short cycle fluctuation component to the long cycle fluctuation component. Inside.

  The control gain K (K> 0) in the control gain unit 22 is an adjustment term that determines the control sensitivity of the filter time constant setting unit 16 with respect to the active power fluctuation component signal absolute value | ΔPG |. When the control gain K is increased, the compensation frequency region is easily expanded with respect to the increase in the active power fluctuation component signal absolute value | ΔPG |, and the compensation amount is increased. On the other hand, when the control gain K is decreased, the compensation frequency region is not easily expanded with respect to the increase in the active power fluctuation component signal absolute value | ΔPG |, so that the compensation amount is suppressed. In actual devices, for each short-term power fluctuation, the actual equipment is adjusted appropriately to ensure a sufficient amount of compensation in preparation for excessive and sudden power fluctuations while securing the necessary compensation amount. .

  With the configuration of FIG. 2, the smaller the active power fluctuation component signal absolute value | ΔPG | is, the smaller the high-pass filter time constant in the active power fluctuation component extraction filter 15 is. Becomes wider (ie, only higher frequency components are extracted).

  Conversely, as the active power fluctuation component signal absolute value | ΔPG | increases, the high-pass filter time constant in the active power fluctuation component extraction filter 15 increases, and the low frequency region to be cut in the active power fluctuation component extraction filter 15 becomes narrower ( That is, even lower frequency components are extracted).

<Effect>
As described above, the active power fluctuation is controlled by feedback control of the filter time constant of the active power fluctuation component extraction filter so that the compensation frequency region is expanded to a lower frequency as the active power fluctuation component signal absolute value | ΔPG | increases. While the component signal absolute value | ΔPG | is small, excessive and rapid power fluctuations (especially EDC control cannot follow up) by limiting the compensation frequency region to the necessary minimum (only for short-period power fluctuations). It is possible to secure a sufficient compensation margin in preparation for an excessive and sudden fluctuation that affects the adjustment capacity (the reason will be described in <Verification Result> described later). When the active power fluctuation component signal absolute value | ΔPG | becomes large, that is, for excessive and sudden power fluctuations, the compensation frequency region is expanded from short cycle power fluctuations to long cycle power fluctuations. Thus, the maximum compensation can be performed using the secured compensation margin.

  Note that the lower limit value Tmin ensures that a necessary amount of compensation can be ensured because power fluctuations in a short cycle (particularly fluctuations in the governor-free region and LFC region where the frequency adjustment capacity is small) are always within the compensation frequency region.

  Since EDC has a slow response speed, control may not be able to catch up with excessive and rapid load fluctuations, but the fluctuation range that can cope with slow fluctuations is large. Therefore, if only excessive and rapid power fluctuations are suppressed in the present method, even if a slow long-period fluctuation component is removed from the compensation region, it can be handled by EDC and does not cause a problem.

  Further, as a method of suppressing the capacity of the power storage amount against power fluctuation, a method of variably controlling the gain can be considered. However, when the gain is controlled, the size is uniformly limited regardless of the fluctuation period, and a necessary amount of compensation for short-period fluctuation cannot be obtained, which is not appropriate.

  Here, the configuration of the active power fluctuation component extraction filter 15 is not limited to the example illustrated in FIG. 2, and may be configured as illustrated in FIG. 3, for example. In the example shown in FIG. 3, the same characteristics as the high-pass filter are realized as a whole by the configuration using the low-pass filter. By extracting the component in the low-frequency region by the low-pass filter and subtracting it from the original signal, A component in a high frequency region, that is, a fluctuation component can be extracted. When the filter time constant command value TO increases, the time constant of the low-pass filter increases, so the pass region in the low-pass filter, that is, the low-frequency region to be cut becomes narrower, and even lower frequency components are extracted.

<Verification results>
About the effect of the electric power stabilization system using the electric power storage apparatus demonstrated above, the verification result by this inventor is shown below.

  Here, the measured waveform of the stabilized output (the total value of the wind power generator output and the power stabilization system output) when the control of the filter time constant setting unit 16 is validated is shown in FIG. FIG. 5 shows a simulation result of the output after stabilization when the control is invalidated. For comparison, FIGS. 4 and 5 also show the actual measured waveforms of the wind power generator output (the waveforms before compensation).

  Since it is difficult to invalidate the control of the filter time constant setting unit 16 in an actual machine, even if the filter time constant control is invalidated, the output of the wind power generation to be compensated cannot be reproduced due to wind. Modeling a power stabilization system using a power storage device with time constant control disabled, and inputting the wind power output data measured in the actual machine (control enabled) (that is, inputting the same data), the above simulation I'm getting results.

  Further, the filter time constant when the control of the filter time constant setting unit 16 is validated is variable between 20 minutes and 250 minutes. Further, the filter time constant when the control of the filter time constant setting unit 16 is disabled is fixed at 120 minutes.

  4 and 5, it can be seen that the wind power generator output changes rapidly from 1500 kW to 0 kW and 1500 kW from 12:30 to 13:00. In contrast, it can be seen that the power stabilization system satisfactorily suppresses power fluctuations regardless of whether the control of the filter time constant setting unit 16 is valid or invalid. The power fluctuation reduction rate at this time (which indicates how much the maximum power fluctuation for 20 minutes has been reduced before and after compensation) is about 88% regardless of whether the control of the filter time constant setting unit 16 is valid or invalid. When the control of the filter time constant setting unit 16 is enabled, the filter time constant during this period is about 250 minutes.

  By the way, as shown in FIG. 4, when the control of the filter time constant setting unit 16 is enabled, the power fluctuation remains slightly from 1:00 to nearly 8:00, but the power fluctuation is followed while following the wind power generator output without delay. It turns out that it suppresses favorably. The reason why the output of the wind power generator is followed without delay is that the active power fluctuation component signal absolute value | ΔPG | during this period is small and the filter time constant is set small by the filter time constant setting unit.

  On the other hand, as shown in FIG. 5, when the control of the filter time constant setting unit 16 is disabled, the power fluctuation is suppressed well from 1:00 to nearly 8:00, but follows the wind power generator output with a slight delay. You can see that The reason for following the wind power generator with a delay is that the time constant is set to a large value of 120 minutes in order to compensate for excessive and rapid power fluctuations.

  Here, since the difference between the wind power generator output and the stabilized output is the amount of power that the power stabilization system compensates for, the less the tracking characteristics with respect to the wind power generator output, the less the power required by the power stabilization system. Increase. As a result of calculating the capacity required for the power storage device in FIGS. 4 and 5, when the control of the filter time constant setting unit 16 is enabled, the capacity required for the power storage device is 26000 kWh, whereas the filter time constant is When the control of the setting unit 16 is disabled, the capacity required for the power storage device is 39000 kWh.

  That is, in order to obtain an equivalent suppression effect against excessive and rapid power fluctuations, a power storage device having a larger capacity is required when the control of the filter time constant setting unit 16 is disabled. On the contrary, when the control of the filter time constant setting unit 16 is enabled, the compensation frequency region is kept to the minimum necessary as long as the absolute value of the active power fluctuation component is small, thereby preparing for excessive and rapid power fluctuation. When sufficient compensation capacity is secured and the absolute value of the active power fluctuation component increases, that is, for excessive and rapid power fluctuations, the compensation frequency range is changed from short-period power fluctuations to long-period power fluctuations. By performing the maximum compensation using the expanded and secured compensation margin, it is possible to obtain the same suppression effect against excessive and rapid power fluctuations with a power storage device having a smaller capacity.

  As a result of the above, it is possible to provide a power fluctuation compensation system using a power storage apparatus that can efficiently and effectively compensate for power fluctuations until an excessive and rapid power fluctuation with a power storage device having a small capacity.

It is a lineblock diagram of a power stabilization system using a power storage device. It is the structural example (the 1) of an active power fluctuation component extraction filter, and the structural example (the 1) of a filter time constant setting part. It is a structural example (the 2) of an active power fluctuation component extraction filter. It is a figure (the 1) which shows a verification result. It is a figure (the 2) which shows a verification result.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Power storage device 2 Bidirectional power converter 3 Transformer 4 Wind generator 5 Transformer 6 Electric power system 10 Control apparatus 11 Operation temperature detector 12 Power storage amount detector 13 Power fluctuation compensation amount adjustment part 14 Active power detector 15 Active power fluctuation component extraction filter 16 Filter time constant setting unit 17 Phase adjustment unit 21 Absolute value calculation unit 22 Control gain unit 24 Filter time constant lower limit limiter

Claims (2)

A power stabilization system that suppresses fluctuations in the active power of an AC power system,
A power storage device for storing power and absorbing power of the AC power system or discharging power to the AC power system;
A bi-directional power converter that mutually converts power input / output accompanying absorption / release of stored power of the power storage device between the AC power system and the power storage device;
By controlling the conversion operation of the bidirectional power converter according to the active power fluctuation of the AC power system, the control device suppresses the active power fluctuation of the AC power system,
The controller is
An active power fluctuation component extraction filter that extracts an active power fluctuation component in a predetermined frequency region according to a set filter time constant from the active power of the AC power system;
A power fluctuation compensation amount adjusting means for controlling a conversion operation of the bidirectional power converter by a power fluctuation compensation amount according to the magnitude of the active power fluctuation component;
Filter time constant setting means for inputting the active power fluctuation component and setting the filter time constant of the active power fluctuation component extraction filter based on the magnitude of the absolute value of the active power fluctuation component;
The filter time constant setting means sets the filter time constant so that the frequency region in the active power fluctuation component extraction filter becomes narrow when the absolute value of the active power fluctuation component is small. When the absolute value of the active power fluctuation component is increased, the filter time constant is set so that the frequency domain becomes wider when the absolute value of the active power fluctuation component is increased. A power stabilization system using a power storage device, characterized in that a low frequency region to be narrowed. A power stabilization system for suppressing fluctuations in active power of an AC power system, the power storage device storing power and absorbing power in the AC power system or discharging power to the AC power system, and the power storage Bidirectional power converter that mutually converts power input / output accompanying absorption / release of stored power of the device between the AC power system and the power storage device, and according to active power fluctuation of the AC power system In the control device in the power stabilization system comprising the control device that suppresses the active power fluctuation of the AC power system by controlling the conversion operation of the bidirectional power converter,
An active power fluctuation component extraction filter that extracts an active power fluctuation component in a predetermined frequency region according to a set filter time constant from the active power of the AC power system;
A power fluctuation compensation amount adjusting means for controlling a conversion operation of the bidirectional power converter by a power fluctuation compensation amount according to the magnitude of the active power fluctuation component;
Filter time constant setting means for inputting the active power fluctuation component and setting the filter time constant of the active power fluctuation component extraction filter based on the magnitude of the absolute value of the active power fluctuation component;
The filter time constant setting means sets the filter time constant so that the frequency region in the active power fluctuation component extraction filter becomes narrow when the absolute value of the active power fluctuation component is small. The frequency range is widened, and when the absolute value of the active power fluctuation component becomes large, the filter time constant is set so that the frequency area in the active power fluctuation component extraction filter is widened, thereby cutting the filter. A control device in a power stabilization system, characterized in that a low frequency region to be narrowed.