JP5598896B2 - Frequency stabilization system for power system - Google Patents

Description

  The present invention relates to a frequency stabilization system for an electric power system, and is particularly useful when applied to a large number of power generation facilities with unstable power generation amounts, such as wind power generation facilities whose power generation amounts vary greatly depending on wind conditions. is there.

  In the power system, the amount of power generated by the power plant and the amount of power received by consumers must always be the same. For example, when the power generation amount exceeds the amount of power reception, the frequency of the power system increases from the reference frequency (for example, 50 Hz), and decreases in the opposite case. The frequency of the power system needs to be within a certain reference value (for example, 50 ± 0.2 Hz), and each electric power company adjusts the power generation amount according to the amount of power received that varies from time to time. LFC: Load Frequency Control) capacity is prepared. However, if a large amount of power generation equipment using natural energy such as wind power generation whose power generation varies greatly depending on the wind conditions is introduced into the power system, the current LFC capacity will absorb all fluctuations in the power generation output. This is not possible and the frequency of the system may fluctuate greatly. Therefore, such fluctuations in the amount of power generation are an obstacle to the introduction of wind power generation facilities and the like into the power system.

  Incidentally, the introduction of natural energy has been promoted as a countermeasure to the global warming problem in recent years. In this case, the amount of generated power depends on the natural environment, and the output power fluctuates greatly. When a large number of such unstable power supplies are connected to the power system, it is expected that it is difficult to maintain the frequency quality of the power system. Furthermore, with the spread of inverter-type air conditioners and the like, the number of devices that receive a certain amount of power is increasing regardless of the frequency of the power system, and loads with various characteristics are connected to the power system. System frequency control is becoming increasingly difficult.

  On the other hand, frequency fluctuation countermeasures that have been generally performed in the prior art centered on power plant output adjustment and a system that uses a centrally controlled large-scale energy storage system. There is a limit to the response speed of the equipment, and installation is expensive. In addition, since the energy storage device for adjusting the power supply frequency does not generate energy, the introduction thereof leads to an increase in energy cost and results in a decrease in energy efficiency.

  Controls frequency fluctuations caused by fluctuations in customer load input even in independent power systems where consumers and power generation equipment are connected one-to-one or in independent power systems consisting of a small number of customers and power generation equipment Patent Document 1 is a publicly known document disclosing a frequency adjustment system in a power system that can be used. In a frequency adjustment system connected to an independent power system that supplies power to a single or a plurality of consumers, charging / discharging means connected to the independent power system for charging and discharging power, and charging / discharging means charging and discharging Charge / discharge control means for controlling the amount of charge / discharge to be discharged; consumer power measurement means for measuring the power supplied to the consumer provided at the receiving end of the consumer; and the frequency of the power grid connected to the power grid Frequency measurement means for measuring, and the charge / discharge control means is configured to control the charge / discharge amount using active power and frequency as control target signals and to keep the frequency of the power system within a predetermined range.

JP 2008-178215 A

  The frequency adjustment system disclosed in Patent Document 1 as described above includes a charge / discharge device, and adjusts the frequency of the power system by controlling the charge / discharge amount in the charge / discharge device. As a result, it becomes a cause of economic deterioration. In addition, since a reverse power flow is generated, it is necessary to take another countermeasure. That is, as disclosed in Patent Document 1, in order to stabilize the frequency by charging and discharging, it is necessary to perform intensive control from the system operator, and when a plurality of consumers perform charging and discharging individually, They may interfere with each other and increase the frequency fluctuation.

  An object of the present invention is to provide a frequency stabilization system for a power system capable of performing frequency adjustment using a load widely dispersed in the power system in view of the above-described conventional technology.

The first aspect of the present invention for achieving the above object is as follows:
When the frequency of the AC power received with respect to a predetermined reference frequency in the power system increases, the amount of power received is increased according to the amount of increase in the frequency, and when the frequency decreases, the frequency A power reception amount control load that is controlled so as to decrease the power reception amount according to a decrease amount is connected in parallel to the power system together with other general loads,
Furthermore, the required power generation increase required to maintain the power supply-demand balance in the power system, and the frequency characteristic constant of the received power control load, which is the received power increase per unit frequency of the received power control load, The power system frequency stabilization system is configured to control the power reception amount with respect to the power reception amount control load by adding the frequency shift amount obtained based on the frequency to the AC power frequency.

  According to this aspect, the frequency of the power system is maintained at the reference frequency based on the required increase in power generation required to maintain the power supply-demand balance in the power system and the frequency characteristic constant of the received power control load. Since the amount of power received with respect to the received power control load can be increased or decreased as described above, in addition to the same operations and effects as in the first aspect, the frequency required to maintain the power supply-demand balance in the power system Control can also be performed. That is, by suppressing the fine frequency fluctuation in the unit of several seconds of the power system with the same components as in the first aspect, and at the same time, taking into account the required power generation increase amount and the frequency characteristic constant of the power reception amount control load as described above The power reception amount control load can be substituted for the LFC capacity, and the deviation of the system frequency with respect to the reference frequency remaining in the first embodiment can be suppressed to zero as much as possible.

The second aspect of the present invention is:
When the frequency of the AC power received with respect to a predetermined reference frequency in the power system increases, the amount of power received is increased according to the amount of increase in the frequency, and when the frequency decreases, the frequency A power reception amount control load that is controlled so as to decrease the power reception amount according to a decrease amount is connected in parallel to the power system together with other general loads,
A plan setting received power amount further power receiving amount of the received power amount control load was set to be an amount in line with the plan set in advance, the amount of received power said a received power increment per unit frequency of the power receiving amount control load A frequency shift amount obtained based on a frequency characteristic constant of a control load is added to the frequency of the AC power to control the power reception amount with respect to the power reception amount control load. In the system.

  According to this aspect, the amount of frequency shift obtained based on the planned amount of received power and the frequency characteristic constant is added to the frequency of the AC power to control the amount of power received for the received power control load. For example, an electric power company can freely control the amount of demand in each time zone. That is, it is possible to determine the optimum amount of frequency shift for the power system by optimally allocating the total charge power amount for the received power amount control load for each time zone. For example, it is possible to bottom up the daily load curve by increasing the charging power in the lowest load time zone at midnight. The bottom-up of the daily load curve can increase the operating rate of the base power source with low power generation cost, which can contribute to the improvement of the economy of the power supply source.

The third aspect of the present invention is:
When the frequency of the AC power received with respect to a predetermined reference frequency in the power system increases, the amount of power received is increased according to the amount of increase in the frequency, and when the frequency decreases, the frequency A power reception amount control load that is controlled so as to decrease the power reception amount according to a decrease amount is connected in parallel to the power system together with other general loads,
Furthermore, the plan-set power reception set so that the required power generation increase necessary to maintain the power supply balance in the power system and the power reception amount of the power reception control load are in accordance with the preset plan. The amount of frequency shift obtained based on the amount of power added to the amount of power and the frequency characteristic constant of the received power control load, which is the increase in received power per unit frequency of the received power control load, is added to the frequency of the AC power. The power system frequency stabilization system is configured to control the power reception amount with respect to the power reception amount control load.

  According to this aspect, not only can the deviation of the system frequency with respect to the reference frequency obtained in the second aspect be suppressed to zero as much as possible, but also the bottom of the daily load curve obtained in the third aspect. Economic system management can also be realized by improving the system.

The fourth aspect of the present invention is:
In the frequency stabilization system for a power system according to any one of the first to third aspects,
The power reception amount control load includes power conversion means for converting input power supplied from the power system, and a frequency shift amount obtained by dividing the required power generation increase amount by a frequency characteristic constant of the power reception amount control load. Comparing means for comparing the reference frequency with the frequency obtained by adding to the actual measurement value of the frequency of the power system and outputting a deviation signal representing the deviation between the two,
Control means for controlling the output power of the power conversion means based on the deviation signal;
A power system frequency stabilization system comprising: a variable amount of received power to which the output power is supplied.

  According to this aspect, the frequency adjustment can be performed individually on the load side by adjusting the power supplied to the variable amount of received power by adjusting the output power of the power converter according to the fluctuation of the frequency of the power system. it can. At the same time, a frequency obtained by adding the frequency shift amount to the actual measurement value of the frequency of the power system and the reference frequency can be compared, and each power reception variable load can be controlled based on the deviation between the two. As a result, the deviation of the system frequency with respect to the reference frequency that remains in the first embodiment can be suppressed to zero as much as possible.

According to a fifth aspect of the present invention,
In the frequency stabilization system for a power system according to any one of the first to third aspects,
The power reception amount control load includes power conversion means for converting input power supplied from the power system,
The measured value of the frequency of the power system is compared with the frequency obtained by subtracting the frequency shift amount obtained by dividing the required increase in power generation by the frequency characteristic constant of the received power control load from the reference frequency. A comparison means for outputting a deviation signal representing the deviation of
Control means for controlling the output power of the power conversion means based on the deviation signal;
A power system frequency stabilization system comprising: a variable amount of received power to which the output power is supplied.

  According to this aspect, the frequency adjustment can be performed individually on the load side by adjusting the power supplied to the variable amount of received power by adjusting the output power of the power converter according to the fluctuation of the frequency of the power system. it can. At the same time, the frequency obtained by subtracting the frequency shift amount from the reference frequency and the actually measured frequency of the power system can be compared to control the variable power reception load based on the deviation between the two. As a result, the deviation of the system frequency with respect to the reference frequency that remains in the first embodiment can be suppressed to zero as much as possible.

According to a sixth aspect of the present invention, in the frequency stabilization system for a power system described in the first, third, fourth, or fifth aspect,
The required power generation increase amount is obtained based on a detected power in a tidal current detecting means for detecting a tidal current of an interconnection line connecting a plurality of power systems and a deviation of the frequency of the power system with respect to the reference frequency. In the power system frequency stabilization system.

  According to this aspect, by controlling the supply and demand balance in the power system, it is possible to suppress fluctuations in the interconnected power flow and to satisfactorily suppress frequency fluctuations.

  In addition, the daily load curve can be bottomed up, and economic system management can be realized by this bottom up.

  According to the present invention, it is possible to perform individual frequency adjustment on each load side using a received power control load that does not need to receive power with constant power, and to adjust output at a power plant and large-scale energy. The overall frequency adjustment of the power system can be satisfactorily realized without depending on the adjustment system. Therefore, even if wind power generation facilities with unstable power generation are connected, stable frequency adjustment can be easily achieved by simply connecting a received power control load that matches the power generation capacity of these wind power generation facilities. It can be carried out.

  Furthermore, it is possible to determine the optimal amount of frequency shift for the power system by optimally allocating the total charged power amount per day for the received power control load to each time zone, and to achieve a bottom-up of the daily load curve. Can do.

  As a result, it is possible to contribute to the active introduction of power generation facilities that use natural energy, which generally has unstable power generation, into the power system, and to that extent, a power system that is friendly to the natural environment can be constructed. In particular, it has a remarkable effect when used at night when the LFC capacity decreases.

  Furthermore, it is possible to improve the economy of the power supply source by bottom-up of the daily load curve.

It is a block diagram which shows the frequency stabilization system of the electric power system which concerns on the 1st Embodiment of this invention. It is a block diagram which extracts and shows the part of the electric power reception amount control load of FIG. It is a characteristic view which shows an example of the frequency control which concerns on the 1st Embodiment of this invention. It is a characteristic view which shows the simulation result of the frequency control which concerns on the 1st Embodiment of this invention. It is a block diagram which shows the frequency stabilization system of the electric power grid | system which concerns on the 2nd Embodiment of this invention. FIG. 6 is a block diagram showing an extracted portion of the power reception amount control load in FIG. 5. It is a characteristic view which shows the simulation result of the frequency control which concerns on the 2nd Embodiment of this invention. FIG. 6 is a block diagram showing another example of a portion of the power reception amount control load in FIG. It is a block diagram which shows the frequency stabilization system of the electric power grid | system which concerns on the 3rd Embodiment of this invention. It is a characteristic view which shows an example of the daily load curve of the electric power grid | system of 3rd Embodiment shown in FIG. It is a block diagram which shows the frequency stabilization system of the electric power grid | system which concerns on the 4th Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram showing a frequency stabilization system for a power system according to the first embodiment of the present invention. As shown in FIG. 1, a plurality of power generation facilities 2, a general load 3, and a power reception amount control load 4 are connected to the system power line 1. Here, there are no special restrictions on the power generation equipment, such as thermal power generation equipment, hydroelectric power generation equipment, etc. It can be installed without problems. Therefore, only the wind power generation facility is exemplarily shown in the figure. The power reception amount control load 4 is a load capable of changing the power reception amount. When the frequency of the AC power received with respect to a predetermined reference frequency in the power system increases, the frequency increase is performed. Control is performed to increase the amount of power received according to a large amount and to decrease the amount of power received according to the amount of frequency decrease when the frequency decreases. A plurality of such received power amount control loads 4 are connected in parallel to the system power supply line 1 together with many other general loads 3.

FIG. 2 is a block line showing an extracted portion of the power reception amount control load 4. As shown in the figure, the power reception amount control load 4 includes a power conversion device 5, a comparator 6, a control device 7, and a power reception amount variable load 8. Here, the power converter 5 converts input power supplied from the system power line 1 into appropriate output power. As an AC / DC power converter, a rectifier using a thyristor as a rectifier, AC / DC The AC power conversion device can be suitably configured by a device that once rectifies to direct current using a rectifier using a thyristor and then reconverts it to a predetermined alternating current using an inverter using a thyristor. However, it is needless to say that the power conversion device 5 is not limited to these. The comparator 6 compares a predetermined reference frequency f ₀ with an actual measurement value of the frequency f of the system power line ₁ and outputs a deviation signal Se ₁ representing the deviation between the two. The controller 7 controls the output power of the power converter 5 on the basis of the deviation signal Se _1. Specifically, when the power converter 5 uses a thyristor, the conduction angle is controlled. The power receiving amount variable load 8 is supplied with the output power of the power conversion device 5. Specifically, the power receiving device only needs to be able to store a certain amount of electric power as electric energy, within a range satisfying a predetermined temperature condition. If it exists, it can comprise suitably with a refrigerator, a vending machine, etc. which can control received electric energy. Here, the power storage device is a DC load, and the refrigerator and the vending machine are AC loads. Accordingly, predetermined power is supplied to the former via the rectifier and to the latter via the inverter. Thus, the received power variable load 8 in this embodiment may be a DC load or an AC load. However, it is optimal for the electric power system to use an electric vehicle that travels by consuming electric energy during the day and stores electric energy mainly at night. This is because not only the surplus nighttime electric power can be used, but also a good frequency adjustment can be performed by complementing the decrease in the LFC capacity. Compared to charging with the maximum charging power, charging takes longer time by adjusting the charging power according to the present invention. Especially when the electric vehicle is a plug-in hybrid vehicle, it is charged at night. When an unscheduled situation occurs and the vehicle needs to be used, it can be run as a gasoline car, so it can handle unscheduled situations as a vehicle even during charging. There is also an effect.

When the rated maximum power of the received power variable load 8 in the above embodiment is Pmax, the reference frequency f ₀ (f ₀ = 50 Hz in the Kanto region) is received at 0.5 Pmax at the reference frequency, When the power frequency decreases by ΔHz, the received power is set to zero, and when the power frequency increases, the received power is set to increase to Pmax. Pin in a range exceeding ± ΔHz is constant, and the middle is controlled in proportion to the frequency change width. . The measured power supply frequency is f, the reference frequency is fo, and the received power Pin is expressed by the following equation.

Pin = 0.5 Pmax {1 + (f-f ₀ ) / Δ} [-1 ≤ (f-f ₀ ) / Δ) ≤ 1] (1)
Pin = 0 [(f-f ₀ ) / Δ) <-1] (2)
Pin = Pmax [1 <(f-f ₀ ) / Δ)] (3)

  As an actual control example, Δ = about 0.2 Hz is desired.

  Such control in the present embodiment is performed while actually measuring the frequencies individually without requiring any mutual adjustment between consumers.

In order to specifically confirm the effect of this embodiment, the following simulation was performed. The conditions are as follows.
1) Capacity of power system (electric power demand at reference frequency): 6085 MW
2) LFC capacity of power system: 99MW
Here, LFC is a range of capacity that can change the power generation output of the generator in order to eliminate the excess or deficiency of power generation in the power system, and to simulate the output change characteristics of each generator. The standard model (thermal power plant and hydroelectric power plant) at the Institute of Electrical Engineers of Japan was used.
3) Rated capacity of wind power generation equipment connected to the power grid: 1200 MW
A simulation of the output waveform of wind power generation was input to the frequency simulation model. The maximum output fluctuation range is 40% of the rated output (480 MW).
An electric vehicle storage battery is assumed as the variable amount 8 of received power.

  Here, the time constant of the storage battery (response speed with respect to the power supply frequency) was 1 second. Incidentally, the time constant in the case of a thermal power plant is about 10 seconds. Further, the frequency response characteristics are those when the rated maximum power Pmax is 1000 W and have the characteristics shown in FIG.

  The simulation result based on such conditions is shown in FIG. In FIG. 4, the thin solid line does not perform the frequency control shown in FIG. 3, and the dotted line performs the frequency control shown in FIG. 3 by using a storage battery of a total of 50 MW electric vehicles (100,000 units) as the power reception variable load 8. In this case, a dark solid line indicates a case where the frequency control shown in FIG. 3 is performed by using a storage battery of a total of 150 MW electric vehicles (300,000 units) as the power reception variable load 8.

  Referring to FIG. 4, when there is no variable power receiving load 8 in this embodiment, the frequency fluctuation reaches 0.4 Hz, whereas 100,000 electric vehicles that are the variable power receiving load 8 are provided. When connected and frequency adjusted with a load capacity of 50 MW, about 0.2 Hz, and when 300,000 electric vehicles are connected and frequency adjusted with a load capacity of 150 MW, up to about 0.1 Hz It can be seen that the frequency fluctuation is suppressed. That is, it can be seen that the electric vehicle in this case functions as an alternative to the LFC capacity.

  As described above, according to the present embodiment, in the power reception on the consumer side, in the power reception of devices such as electric cars, refrigerators, and vending machines that do not need to maintain a constant power reception amount, the power reception amount is set to the frequency of the power system. By adjusting correspondingly, it is possible to absorb frequency fluctuations of the power system. Such frequency control can be performed individually by each customer based on the detected frequency of the power system, and there is no need to centrally manage the received power control load that is a power receiving control device. Has great advantages. In addition, instead of building an energy storage device or the like separately, the energy storage capacity of a device that a customer originally needs for another purpose (for example, traveling in the case of an electric vehicle) can be used for frequency adjustment as it is. Therefore, it is extremely advantageous from the viewpoint of energy efficiency and cost.

  Furthermore, although the case where the frequency characteristic shown in FIG. 3 is fixed to one type has been described in the first embodiment, a plurality of types of output power patterns to be output to the power converter 5 may be prepared. . For example, in a specific time zone in midsummer daytime when the power demand reaches a peak, in the characteristic diagram shown in FIG. 3, a characteristic line is drawn in the left direction in the figure so that the charge power at the reference frequency fo is shifted from 500 W to 400 W. Frequency control is performed using the translated map information. This makes it possible to perform accurate frequency control that reflects the actual situation of power demand that varies depending on the season and time zone. Here, such map information is stored in the control device 7.

  5 and 6 are diagrams showing a frequency stabilization system for an electric power system according to a second embodiment of the present invention. FIG. 5 is a block diagram thereof, and FIG. 6 is a part of the received power control load 14. It is a block diagram extracted and shown.

  The present embodiment has all the components of the frequency stabilization system according to the first embodiment, and further eliminates as much as possible the deviation of the system frequency from the reference frequency that remains in the first embodiment. It can be suppressed. Therefore, in FIG. 5 and FIG. 6, the same parts as those in FIG. 1 and FIG.

As shown in FIG. 5, in this embodiment, the system power line 11 of another power system is connected to the system power supply line 1 via the interconnection line 12. A number of general loads 3 are connected to the system power line 11.

The tidal current detection unit 13 is connected in the middle of the interconnection line 12. The tidal current (power amount) transmitted through the interconnection line 12 and the tidal frequency relative to the reference frequency f ₀ (measurement of the system power line 1). The deviation Δf of the equivalent frequency f) is detected. Thus, the required power generation increase amount AR (W) required for maintaining the power supply / demand balance in the system power line 1 based on the deviation Δf is obtained, and the required power generation increase amount AR and the unit of the received power control load 14 are further obtained. The frequency shift amount f _shift to be supplied to the power reception amount control load 14 is determined based on the frequency characteristic constant K _p (W / Hz) of the power reception amount control load 14 that is the amount of increase in the power reception power per frequency. That is, a shift signal representing the frequency shift amount f _shift obtained by the calculation of the following equation (4) is sent to each power reception amount control load 14.

f _shift = − (AR / K _p ) (4)

Here, the frequency characteristic constant K _p (W / Hz) of the received power control load 14 is determined in advance by the characteristics of the received power control load 14.

The required power increase amount AR as described above is an amount of power necessary to maintain the supply and demand balance in the area where the system power supply line 1 is provided. Therefore, even if the demand amount is reduced by the same amount as the required power generation increase amount AR. It is possible to maintain a balance between supply and demand in the region. This is a signal in which the shift signal representing the frequency shift amount f _shift calculated by the above equation (4) is transmitted to all the received power control loads 14 at the same time, and the frequency f of the system power line 1 is shifted by the frequency shift amount f _shift. Can be realized by controlling the received power control load 14. This is equivalent to controlling the apparent frequency viewed from the power reception amount control load 14 side.

The shift signal representing the frequency shift amount f _shift is transmitted collectively to each power reception amount control load 14 via a transmitter (not shown) built in the power flow detection unit 13. Here, as shown in FIG. 6, the power reception amount control load 14 in this embodiment has a receiver 16, and the receiver 16 receives the shift signal. The frequency shift amount f _shift based on the shift signal is added to the actually measured frequency f of the system power supply line 1 by the adder 17 and compared with the reference frequency f ₀ set in the reference frequency setter 15 by the comparator 6 as f + f _shift. Is done. Note that f _shift > 0 when AR <0, and f _shift <0 when AR> 0. As a result, the power conversion device 5 that is controlled via the control device 7 based on the deviation signal Se ₂ that is the output signal of the comparator 6 is controlled on the assumption that the frequency f of the system power supply line 1 is apparent (f + f _shift ). Thus, the received power supplied to the received power variable load 8 is adjusted so that the required power generation increase amount AR in the system power supply line 1 becomes zero. If the required power increase amount AR becomes zero, naturally, the balance of supply and demand is maintained in the system power supply line 1, so that the system frequency is maintained at the reference frequency, and fluctuations in the interconnection power flow are eliminated.

In this embodiment, since the frequency shift amount f _shift in consideration of the required power generation increase amount AR is added as a parameter for power reception amount control of each power reception amount control load 14, each power reception amount control load 14 has a frequency f of the system power line 1. Is received (f + f _shift ), and the received power supplied to the received power variable load 8 is adjusted. As a result, the received power supplied to the received power variable load 8 is adjusted so that the required power increase AR in the system power line 1 becomes zero, and the system frequency relative to the reference frequency that remains in the first embodiment is adjusted. The deviation can be suppressed to zero as much as possible.

  FIG. 7 is a characteristic diagram showing a simulation result of frequency control according to the present embodiment. In FIG. 7, when the frequency control according to the first embodiment and the frequency control according to the present embodiment (second embodiment) are not performed, the light gray solid line indicates the dark gray solid line of the first embodiment. When only the frequency control according to the embodiment is performed, the black solid line indicates the case where the frequency control according to the present embodiment is performed together with the frequency control according to the first embodiment.

  Referring to FIG. 7, when there is no power reception amount control load 14 in this embodiment, the frequency fluctuation reaches 0.16 Hz, whereas only the power reception amount control load 4 in the first embodiment. In the case of having the power reception amount control load 14 in the present embodiment, the frequency fluctuation in the case of having only the power reception amount control load 4 is also suppressed and approaches zero as much as possible. I understand that.

In the second embodiment, the tidal current detecting unit 13 detects the telecommunication frequency tidal power transmitted via the telecommunication line 12 and the tidal frequency deviation Δf with respect to the reference frequency f _0. However, the present invention is not limited to this. Of course not a thing. For example, it is naturally possible to perform measurement in a central control room that manages the operation of the system. Moreover, although 2nd Embodiment is the case where the system power line 11 of another power system is connected to the system power supply line 1 via the interconnection line 12, it is not restricted to this. Even a single system can be applied without limitation as long as it is a system that manages the required power generation increase amount AR, and the same effect can be obtained.

As shown in FIG. 8, the shift signal representing the frequency shift amount f _shift that is collectively transmitted from the transmitter (not shown) built in the power flow detector 13 in FIG. Even if it is received by the receiver 26 of the control load 24 and the frequency shift amount f _shift is subtracted from the reference frequency f ₀ by the subtractor 27 and compared with the frequency f by the comparator 6 as f ₀ -f _shift , it is A deviation signal Se ₂ similar to that of the embodiment can be obtained. Therefore, the power reception amount control load 24 may be configured as shown in FIG. Also in this example, f _shift > 0 when AR <0, and f _shift <0 when AR> 0.

In the present embodiment, the frequency shift amount f _shift is transmitted from the power flow detector 13 connected in the middle of the interconnection line 12, but is not limited thereto. Of course, the connection line 12 may not be provided, and it may be sent from a central power supply command station or the like.

  FIG. 9 is a block diagram showing a frequency stabilization system for a power system according to the third embodiment of the present invention.

This embodiment has all the components of the frequency stabilization system for the power system according to the first embodiment, and further, the frequency shift amount f _shift described in the second embodiment is changed to the second The present invention is not applied to the LFC as in the embodiment, but is applied to an economic load distribution control (EDC). Therefore, in FIG. 9, the same parts as those in FIGS.

As shown in FIG. 9, in this embodiment, a shift signal representing the frequency shift amount f _shift is sent from the central power supply command station 23 toward each power reception amount control load 14. Here, the frequency shift amount f _shift in the present embodiment is the planned power reception amount AR ′ (w) set so that the power reception amount of the power reception amount control load 14 is in accordance with a predetermined plan, and the frequency characteristic constant K _p. And based on the following equation (5).

f _shift = − (AR ′ / K _p ) (5)

As shown in the above equation (5), the frequency shift amount f _shift in this embodiment is obtained by substituting the required power generation increase amount AR in equation (4) with the planned power reception amount AR ′.

As a result, the power reception amount of each power reception amount control load 14 is controlled by adding the frequency shift amount f _shift to the frequency f of the AC power supplied from the system power line 1. That is, each received power control load 14 adjusts the received power supplied to the received power variable load 8 assuming that the frequency f of the system power supply line 1 is apparently (f + f _shift ), as in the second embodiment. .

  Here, the planned power reception amount AR ′ is determined based on the daily load curve of the power system. An example of the daily load curve is shown in FIG. As shown in the figure, for example, when optimally allocating the total charge power amount of the received power control load 14 to each time zone, the charge power is increased in the lowest load time zone at midnight to increase the daily load curve. The plan will allow bottom-up. That is, the shaded portion of the daily load curve as originally shown by the solid line in FIG. 10 is lifted and the minimum load time zone (in the case shown in FIG. 10, the time zone from about 1 am to past 6 am) Set the load as indicated by the alternate long and short dash line. FIG. 10 shows a case where nuclear power generation is applied as the base power source, and the shortage is successively covered by LNG power generation and oil power generation. In this case, the power generation cost per unit power increases in the order of nuclear power, LNG, and petroleum.

The nuclear power generation operation rate, which is the base power source with the lowest power generation cost, can be raised as indicated by an arrow A in the figure by bottom-up of the daily load curve as shown by diagonal lines in FIG. That is, the power in the shaded area shown by 10 in the figure is the planned power reception amount, and the central power supply command station 23 allocates each time and sends a shift signal representing the frequency shift amount f _shift based on the planned power reception amount. To do.

  That is, the central power supply command station 23 in the present embodiment is in accordance with a plan in which the amount of power received by the power reception control load 14 is determined in advance along with functions similar to the conventional ones such as control of the amount of power supplied to the power system including the system power line 1 It also has an EDC function based on the planned power reception amount AR ′ (w) set so as to be an amount.

  FIG. 11: is a block diagram which shows the frequency stabilization system of the electric power grid | system which concerns on the 4th Embodiment of this invention.

  This embodiment combines the functions of the second embodiment and the third embodiment. That is, LFC and EDC are realized simultaneously. Therefore, in FIG. 11, the same parts as those in FIGS. 5 and 9 are denoted by the same reference numerals, and redundant description is omitted.

As shown in FIG. 11, in this embodiment, the power amount obtained by adding the required power generation increase AR and the planned power reception amount AR ′ from the central power supply command station 33 connected in the middle of the interconnection line 12, and the frequency characteristic constant a shift signal representing the K _p and the frequency shift amount f _shift determined based on adapted to deliver toward each received power amount control load 14. That is, the frequency shift amount f _shift in this embodiment is expressed by the following equation (6).

f _shift = − (AR + AR ′ / K _p ) (6)

Each power reception amount control load 14 in this embodiment adds the frequency shift amount f _shift to the frequency f of the AC power supplied from the system power supply line 1, and the frequency f of the system power supply line 1 is apparently (f + f _shift ). The received power supplied to the received power variable load 8 is adjusted.

  As a result, according to this embodiment, by controlling the supply and demand balance in the power system, it is possible not only to suppress fluctuations in the interconnection power flow, but also to suppress frequency fluctuations well, as well as the bottom of the daily load curve. It is possible to improve the system, and it is possible to realize economical system operation by bottom-up.

  The present invention can be effectively used in an industrial field in which a power generation system using natural energy is constructed.

DESCRIPTION OF SYMBOLS 1, 11 System power line 2 Power generation equipment 3 General load 4, 14, 24 Power receiving amount control load 5 Power converter 6 Comparator 7 Control device 8 Power receiving amount variable load 12 Interconnection line 13 Power flow detection part 16, 26 Receiver 17 Adders 23, 33 Central power supply command station 27 Subtractor

Claims (6)

When the frequency of the AC power received with respect to a predetermined reference frequency in the power system increases, the amount of power received is increased according to the amount of increase in the frequency, and when the frequency decreases, the frequency A power reception amount control load that is controlled so as to decrease the power reception amount according to a decrease amount is connected in parallel to the power system together with other general loads,
Furthermore, the required power generation increase required to maintain the power supply-demand balance in the power system, and the frequency characteristic constant of the received power control load, which is the received power increase per unit frequency of the received power control load, A frequency stabilization system for an electric power system configured to control the power reception amount with respect to the power reception amount control load by adding the frequency shift amount obtained based on the frequency to the frequency of the AC power. When the frequency of the AC power received with respect to a predetermined reference frequency in the power system increases, the amount of power received is increased according to the amount of increase in the frequency, and when the frequency decreases, the frequency A power reception amount control load that is controlled so as to decrease the power reception amount according to a decrease amount is connected in parallel to the power system together with other general loads,
A plan setting received power amount further power receiving amount of the received power amount control load was set to be an amount in line with the plan set in advance, the amount of received power said a received power increment per unit frequency of the power receiving amount control load A frequency shift amount obtained based on a frequency characteristic constant of a control load is added to the frequency of the AC power to control the power reception amount with respect to the power reception amount control load. System. When the frequency of the AC power received with respect to a predetermined reference frequency in the power system increases, the amount of power received is increased according to the amount of increase in the frequency, and when the frequency decreases, the frequency A power reception amount control load that is controlled so as to decrease the power reception amount according to a decrease amount is connected in parallel to the power system together with other general loads,
Furthermore, the plan-set power reception set so that the required power generation increase necessary to maintain the power supply balance in the power system and the power reception amount of the power reception control load are in accordance with the preset plan. The amount of frequency shift obtained based on the amount of power added to the amount of power and the frequency characteristic constant of the received power control load, which is the increase in received power per unit frequency of the received power control load, is added to the frequency of the AC power. And a power system frequency stabilization system configured to control the power reception amount with respect to the power reception amount control load. In the frequency stabilization system of the electric power system as described in any one of Claims 1 thru | or 3 ,
The power reception amount control load includes power conversion means for converting input power supplied from the power system,
The frequency obtained by dividing the required increase in power generation by the frequency characteristic constant of the received power control load is added to the measured value of the frequency of the power system and the reference frequency to compare both A comparison means for outputting a deviation signal representing the deviation of
Control means for controlling the output power of the power conversion means based on the deviation signal;
A power system frequency stabilization system comprising: a variable amount of received power to which the output power is supplied. In the frequency stabilization system of the electric power system as described in any one of Claims 1 thru | or 3 ,
The power reception amount control load includes power conversion means for converting input power supplied from the power system,
The measured value of the frequency of the power system is compared with the frequency obtained by subtracting the frequency shift amount obtained by dividing the required increase in power generation by the frequency characteristic constant of the received power control load from the reference frequency. A comparison means for outputting a deviation signal representing the deviation of
Control means for controlling the output power of the power conversion means based on the deviation signal;
A power system frequency stabilization system comprising: a variable amount of received power to which the output power is supplied. In the power system frequency stabilization system according to claim 1, claim 3, claim 4 or claim 5 ,
The required power generation increase amount is obtained based on a detected power in a tidal current detecting means for detecting a tidal current of an interconnection line connecting a plurality of power systems and a deviation of the frequency of the power system with respect to the reference frequency. Power system frequency stabilization system.