JP2003274564A - Method and device for controlling operation of private power generation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize an operation control method for a private power generation system, which enables minimum cost operation by considering the unit cost of the purchased power and the estimated unit cost of generated power. <P>SOLUTION: In this operation control method for a private power generation system which has a plurality of generators 4, when the load becomes two small if the number of generators, for example, is increased from one or the loads is two small for the two units of generators now in operation, the unit cost of the purchased power at that time is compared with the estimated unit cost of the generated power; if the unit cost of the purchased power is lower than the other, the quantity of power to be purchased is increased, and the number of generators in operation is kept to one or the two units in operation area reduced into one (chain 1). Power, the day demand is inputted in advance. And, in the case that to small a load is forecast, the quantity of power to be purchased is increased, and the number of generators is reduced before that. Likewise, when sudden drop in power load is predicted, the quantity of power to be purchased is increased to a quantity not to cause a reverse current, and the number of generators is reduced (chain 3). <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operation control method and an operation control apparatus for a private power generation system, for example, a private private power generation system in which a generator is driven by an axial power generated by burning liquid fuel or gas fuel to generate electric power. The present invention relates to an operation control method and an operation control device for a machine, a cogeneration system that uses exhaust heat, and the like.

[0002]

2. Description of the Related Art A diesel cogeneration system, which is an example of a private power generation system, is shown in FIGS. FIG. 8 is a vertical cross-sectional view of a building front view showing a basic configuration example, FIG. 9 is a vertical cross-sectional view of a building side view showing a basic configuration example, and FIG. 10 is a flow chart showing a basic flow of waste heat, electric power, etc. is there.

The fuel subdivided from the main fuel tank 1 shown in FIG. 8 is temporarily stored in the fuel dispensing tank 2 and supplied to the engine 3 by a fuel supply device (not shown). The shaft power generated by the engine 3 is transmitted to the generator 4 to generate power.

At this time, as shown in FIG. 10, the primary cooling water 5
Turns the engine 3 into hot water. This hot water is sent to the heat exchanger 6, where heat is transferred to generate hot water 7. The hot water 7 is used in the process and also in FIGS.
The steam exhaust gas boiler 8 shown in FIG.
As a result, the exhaust heat emitted from the engine 3 is effectively used.

The exhaust gas passes through the silencer 10 shown in FIG. 9 and is discharged from the chimney 11. When the exhaust heat is not recovered, the exhaust heat is radiated by the cooling tower 13 via the other heat exchanger 12. The above control is performed by the operation control device (see FIG. 1) provided in the control unit 14.

Next, the operation control performed by the operation control device of the private power generation system will be described.

Normally, the power receiving system of the electric power company is always connected to the grid and used for power supply in the office. The power shortage will be received from the power company. If there is a reverse flow contract with an electric power company, surplus power may be reversely transmitted to the electric power company. When there is no reverse power flow, the operation control of the related art can be roughly divided into the following cases 1 to 3. In addition, in FIG. 11, reference numeral 15 indicates a power generation status, and 16 indicates a power reception status.

Case 1. When the power load is almost constant as shown in FIG. 11A, the capacity of the private power generation system is 100.
The size is such that% output operation is performed, and 24-hour operation is performed.

Case 2. In the case of a mountain-shaped power load as shown in FIG. 11 (B), only the top of the mountain is operated (peak cut).

Case 3. When considering the unit price of electricity, see Figure 1.
As shown in 1 (C), the private power generation system is operated at 100% output as much as possible during the day when the power unit price is high, and the private power generation system is stopped at night when the power unit price is low, or the minimum operation for the amount exceeding the contracted power. I do.

Here, in case 1 above and when a contract is made with a power company with reverse power flow, the private power generation system operates at 100% output. However, case 2 above
Alternatively, in case 3, the power generation amount of the private power generation system is controlled according to the current power load condition.

[0012] Specifically, in case 2, the private power generation system is started before the contract power is exceeded, and the private power generation system is used to cover the excess of the contract power to reduce the basic charge and the usage-based charge.

In case 3, when a seasonal contract is carried out and the electric power charge is low at night, the private power generation system is stopped as much as possible, and power is generated only when the contracted power is exceeded.
On the other hand, during the daytime, electricity charges are high, so the private power generation system should be operated as much as possible, and the reduction in basic charges and the reduction in pay-as-you-go charges should bring benefits.

However, the actual electric power load fluctuates, and the private power generation system cannot instantaneously react to this fluctuation, which causes a time lag. Also, the minimum operating capacity is determined by the engine performance. Therefore, the actual operation control is performed with a margin.

Now, in a private power generation system with two generators,
A case where the power load increases or the power load decreases from the state where the power load is 0 will be described. An example of the power generation status of each generator is shown in FIG. 12, an example of a processing procedure when the electric power load increases (1) to 4) described below is shown in FIG. 13, and a processing procedure when the electric load decreases (5) to 6) described later). An example is shown in FIG. Figure 1
In 2, 17 increases the power load from 0 to 3000
The power load states when the power load is increased to kW and then decreased, and 18 and 19 respectively show the power generation states of the first and second units when two 1000 kW generators are used as an example.

Specifically, 1) the power load increases (step S101YE in FIG. 13).
S) If the predicted power generation unit price is lower than the power purchase unit price (YES in step S102), the private power generation system is activated.
However, in this case, the power load exceeds 1 from the time when the minimum power receiving constant value exceeds the minimum operating capacity of the engine and the margin.
Power generation for the second stage is started (step S103 YES → step S104).

2) The power load is further increased (step S10).
7YES) When operating a plurality of units, start the operation of the next unit with a margin before the generator currently in operation becomes 100% output operation (step S). Generally, the operation of the next unit is started at about 80% (step S109 YES →
(Step S110) In the case of two-unit operation, 40% low load operation is performed.

3) When the power load further increases (step S
111YES) Increase the amount of power generation until both units operate 100% (step S112 → step S113NO)
→ Step S111 YES → Step S112 is repeated), and thereafter, the power load is covered by increasing the power purchase amount (Step S113 YES → Step S113).
114).

4) When the unit price of power purchase is higher than the estimated unit price of power generation (NO in step S102), the power load exceeds the value obtained by subtracting the minimum constant power reception value, the minimum operating capacity of the engine, and the margin from the contract power amount. Then, the power generation of the first unit is started (YES in step S106 → step S104).

5) The power load is reduced (step S2 in FIG. 14).
01YES-step S205), when stopping the private power generation system, in consideration of the fluctuation of the power load, after the low load state, specifically, when the single-unit power generation amount reaches about 40%, stop the power generation system (step S205 YES → step S206). As a result, if two units are in operation and the second unit is stopped and only one unit is in operation, the operation will be 80%.

6) The power load is further reduced (step S20).
7 to step S210), when stopping the remaining one generator, in consideration of the fluctuation of the electric power load, after the low load state, specifically, stop the generator after the single-unit power generation amount reaches about 40%. (Step S210 YES → Step S21
1).

[0022]

When the above operation control is performed, there are the following problems.

That is, the number of power generations of the private power generation system is determined according to the current power load, but since the fluctuation (increase / decrease) of the power load is not observed, the number of power generations is increased / decreased with a margin. It is necessary, the low load operation,
That is, the operation becomes inefficient.

In addition, when a contract is made with a power company without reverse power flow, even if the equipment with the maximum capacity is stopped, a certain amount of power is set so that the reverse power flow is not received, and that amount is received from the power company. In this case, when the electric power load is less than the generator capacity + constant electric power received, 100% operation cannot be performed, and operation is performed at a low load with poor fuel economy.

Further, when the facilities are stopped all at once such as during lunch break and the electric power load is drastically reduced, the private power generation system may not be able to follow and a reverse flow may occur. Therefore, it is necessary to take a large constant value for minimum power reception, and economical operation cannot be performed.

The present invention has been made in view of the above circumstances, and an object thereof is to solve the above-mentioned drawbacks of the prior art and to enable a cost-minimum operation in consideration of the purchase price of electricity and the estimated electricity generation rate. An object is to provide an operation control method and an operation control device for a power generation system.

It is another object of the present invention to provide an operation control method and an operation control device for a private power generation system that flexibly copes with load fluctuations and enables cost-minimum operation.

Further, it is an object of the present invention to provide an operation control method and an operation control device for a private power generation system that flexibly responds to a sudden load change such as lunch break without causing a reverse power flow, and that enables a cost-minimum operation. is there.

[0029]

In order to achieve the above object, according to the invention of claim 1, in the operation control method of a private power generation system having a plurality of generators, when the number of generators increases, the load becomes low, or at present. When each generator that is generating electricity has a low load, compare the unit power purchase price at that time with the predicted power generation unit price, and if the power purchase unit price is cheaper, increase the amount of power purchased and Either keep the number of generators low or reduce the number of generators.

Further, in the invention of claim 2, in the operation control method of the private power generation system having a plurality of generators,
If the power daily load is input in advance and a decrease in the power load is predicted by the power load prediction based on the power daily load,
Before the predicted reduction of the electric power load, the amount of power purchased is increased and the number of operating generators is decreased.

According to a third aspect of the invention, in the operation control method of the private power generation system having a plurality of generators,
If the power daily load is input in advance and a sharp decrease in the power load is predicted by the power load prediction based on the power daily load, the power load is calculated before the predicted sharp decrease in the power load. Is increased, the amount of power purchased is increased to the point where the reverse flow does not occur, the operating number of the generators is decreased, and the minimum amount of power received is normally decreased.

According to a fourth aspect of the invention, in the operation control device of the private power generation system having a plurality of generators,
Monitoring means for monitoring the power load and the number of generators in operation, and commercial power at that time when the number of generators increases and the load becomes low, or when each generator currently generating electricity becomes low load Power unit price comparing means for comparing the power purchase unit price of the above with the predicted power generation unit price of the generator, and the result of the comparison,
When the unit price of electric power purchase is cheaper, it is provided with a control means for controlling the number of electric power sources by increasing the amount of electric power purchase and keeping the number of generators small or reducing the number of generators. .

According to the invention of claim 5, in the operation control device of the private power generation system having a plurality of generators,
A predicting unit that predicts a power load based on a previously input power daily load, and, as a result of the prediction, when a decrease in the power load is predicted, an amount to be purchased before the predicted decrease in the power load is set. And a control means for controlling the number of the generators that increases and decreases the number of operating generators.

Further, according to the invention of claim 6, in the operation control device of the private power generation system having a plurality of generators, a prediction means for predicting the power load based on the power daily load inputted in advance, and the prediction result, When the sudden decrease of the power load is predicted, before the predicted sudden decrease of the power load, the amount of power purchase is increased to the point where the reverse flow does not occur due to the sudden decrease of the power load. In addition, a control unit that controls the number of operating generators is provided.

[0035]

1 is a power system diagram including a private power generation system (cogeneration system) used in each embodiment described below.

As shown in the figure, in this system, the commercial power from the commercial grid 50 and the inventive power from the private power generation system (cogeneration system) 51 are optimally combined to reduce the power cost, The electric power is supplied to the load 52 and the important load 53. This system is controlled by the operation controller 54.

The operation control device 54 is provided in the control unit 14, and its functions are to monitor the power load and the number of generators in operation, and when a predetermined condition is satisfied, A power unit price comparison means for comparing the purchased power unit price of commercial power with the predicted power generation unit price of the generator, a prediction means for predicting the power load based on the previously input power daily load, the result of the power unit price comparison, or It is provided with control means for increasing / decreasing the amount of power purchased and controlling the number of operating generators based on the result of the prediction of the power load. The processing procedure in this operation control device 54 will be described in detail in the following first to third embodiments.

<First Embodiment> FIG. 2 is a flowchart showing the processing procedure of the first embodiment executed by the operation control device shown in FIG. This embodiment shows a processing procedure in the case of increasing the power purchase amount and the number of generators in a situation where the power load increases.

The operation of the first embodiment will be described below.
When it is assumed that the power load increases and the number of generators increases, when the power load at that time causes each generator to become a low load due to the increase in the number of generators (step S
1) First, the power purchase unit price is compared with the predicted power generation unit price (step S2). At this time, if the unit price of power purchase is higher (NO in step S2), increasing the amount of power purchase will rather increase the cost. Therefore, in this case, even if the generator has a low load, the state of the windshield is continued (step S2NO → step S1).

On the other hand, when the unit price of power purchase is cheaper (YES in step S2), the cost is lower when the amount of power purchase is increased. Therefore, in this case, the power purchase amount is increased (step S
3). Next, it is confirmed whether or not the amount obtained by adding the power purchase amount and the margin exceeds the contract power (step S4). When it does not exceed (NO in step S4), the power purchase amount can be maintained.

In this case, the number of operating generators remains small even if the electric power load increases (step S6). In this way, if the number of generators to be operated is kept small, the generators maintain high output operation, the efficiency is increased, and the predicted unit price of power generation is decreased. The estimated unit price of power generation will decrease, and the percentage of power purchasers with lower unit prices will increase, as described above, so the total unit price of power generation here will be a minimum.

By keeping the number of operating units small, the operating time can be reduced and the maintenance cost can be reduced. This point is also reflected in the predicted unit price of power generation.

However, as a result of increasing the power purchase amount, if the power purchase amount plus the margin exceeds the contracted power (step S4 YES), the power purchase amount cannot be further increased. In this case, the number of generators is increased in preparation for a further increase in power load (step S5).

FIG. 3 shows a comparative example. This comparative example is 1,
In a private power generation system with two 000kW generators,
In the scene where the electric power load increases, it shows the difference in power generation status between when the conventional method is applied (left side in the figure) and when the method of the first embodiment is applied (right side in the figure). Is.

Specifically, as shown in the figure, when the minimum received power amount is 500 kW, in the conventional case, when the power load increases and two units are operated from one unit, the power generation amount of two units of 400 kW is summed. In contrast to 1300 kW, in the case of the first embodiment, even when the power load is 1300 kW, one unit is in operation, and thereafter, the power purchase amount is increased and one unit is continuously operated (see an example of 1600 kW). Load is 1900
It is possible to reduce the total unit price of electric power by operating two units only after reaching kW.

The same processing is performed when the power load is decreasing. Explaining with reference to the same comparative example of FIG. 3, when the power load becomes less than 1900 kW,
The power purchase amount is increased, and the operation that used to operate two units until then is changed to one device operation. For example, even in the case of a power load of 1600 kW, the increase in the power purchase amount can be dealt with.

<Second Embodiment> Next, a second embodiment will be described. Since the overall system configuration is the same as in FIG. 1, the illustration is omitted and only the processing procedure will be described.
FIG. 4 is a flowchart showing a processing procedure of the second embodiment executed by the operation control device described above.

In the second embodiment, the daily load is input in advance, and future prediction is performed based on the input daily load. At this time, if a decrease in the power load is predicted, the number of operating vehicles is reduced in advance by increasing the power purchase. By doing so, low-load operation is avoided, and the operating state is at a minimum cost.

The operation of the second embodiment will be described below.
First, the future of the electric power load is predicted based on the electric power daily load input in advance (step S11). Here, when the decrease of the power load is not predicted (NO in step S12), it is not necessary to perform new processing. It returns to step S11. On the other hand, when a decrease in power load is predicted (step S12)
YES), the power purchase amount is increased on condition that the power purchase unit price is lower than the expected power generation unit price (YES in step S13 → step S14). Next, it is confirmed whether or not the amount obtained by adding the power purchase amount and the surplus does not exceed the contracted power (step S1).
5). When it does not exceed (NO in step S15), the power purchase amount can be maintained. In this case, the number of operating generators is reduced (step S17).

By thus reducing the number of generators in operation in advance, even if the electric power load subsequently decreases, the generators maintain high output operation, the efficiency increases, and the predicted power generation unit price decreases. By reducing the number of operating units, the operating time can be reduced and the maintenance cost can be reduced. This point is also reflected in the predicted unit price of power generation.

However, as a result of increasing the power purchase amount, if the amount obtained by adding the power purchase amount and the surplus exceeds the contracted power (step S15 YES), the power purchase amount cannot be further increased. In this case, the number of generators is maintained (step S1
6).

FIG. 5 shows a comparative example. This comparative example is 1,
When a conventional method is applied (on the left side of the figure) and a method of the second embodiment is applied (a figure on the same figure) in a scene where a decrease in power load is predicted in a private power generation system with two 000 kW generators. The right side) shows the difference in power generation status. Specifically, as shown in FIG.
When a decrease in the electric power load is predicted in the state of the electric power load of 0 kW, the amount of power purchased is increased and the number of operating generators is reduced in advance. By doing this, for example, even when the power load is reduced to 1600 kW, in the conventional case, the amount of power generation is 550 kW for the constant received power of 500 kW, whereas
According to this embodiment, power purchase is 600 kW and power generation is 100
A high efficiency of 0 kW and a low unit price of power generation are maintained.

<Third Embodiment> Next, a third embodiment will be described. Since the overall system configuration is the same as in FIG. 1, the illustration is omitted and only the processing procedure will be described.
FIG. 6 is a flowchart showing a processing procedure of the third embodiment executed by the operation control device described above. In this embodiment, the daily load is input in advance, and future prediction is performed based on this input. If it is predicted that the power load will suddenly decrease, the amount of power received is increased in advance to avoid reverse power flow,
Normally, the minimum amount of power received should be lowered to avoid low load operation, and the operating state should be at the cost minimum.

The operation of the third embodiment will be described below.
First, the future of the power load is predicted based on the power daily load that has been input in advance (step S21). Here, when the decrease in the power load is not predicted (NO in step S22), it is not necessary to perform new processing. It returns to step S21. On the other hand, when a sharp decrease in the power load is predicted (step S22 YES), the power purchase amount is increased (step S2).
3). Next, it is confirmed whether or not the sum of the power purchase amount and the surplus exceeds the contract power (step S24). When it does not exceed (NO in step S24), the power purchase amount can be maintained. In this case, the number of operating generators is reduced (step S26).

By thus reducing the number of generators in operation in advance, even if the power load sharply decreases thereafter, reverse power flow does not occur, and the generators maintain high output operation. The efficiency will be higher and the forecasted power generation cost will be lower. By reducing the number of operating units, the operating time can be reduced and the maintenance cost can be reduced. This point is also reflected in the predicted unit price of power generation.

However, as a result of increasing the power purchase amount, if the power purchase amount plus the margin exceeds the contracted power (step S24 YES), the power purchase amount cannot be increased any more. In this case, the number of generators is maintained (step S2
5).

FIG. 7 shows a comparative example. This comparative example is 1,
In a private power generation system with two 000kW generators,
Differences in power generation status between when the conventional method is applied (on the left side of the figure) and when the method of the third embodiment is applied (on the right side of the figure) in a scene where a rapid decrease in the power load is predicted. Is shown.

Specifically, in the conventional case, for example, a constant power reception value of 500 kW, a power generation amount of 700 kW, and a power load 19
If the equipment is shut down all at once such as during lunch break from the state of 00 kW and the power load is drastically reduced, it will not be possible to reduce the power generation in a timely manner and it will be a reverse power flow (symbol 2 in the same figure).
0), the protective relay causes the private power generation system to stop.

On the other hand, in the case of the present embodiment, since the daily load is input in advance, if a drastic decrease in the power load is predicted in the same lunch break, the power reception amount is increased in advance before lunch (reference numeral 2).
1) It is possible to prevent reverse power flow even after entering the lunch break and after the power is sharply reduced (reference numeral 22. Note that the lunch break is indicated as daytime in the figure).
In the mornings and afternoons other than this time, by reducing the constant power received (reference numerals 23 and 24), it is possible to reduce the number of power generators and operate with high efficiency, thereby lowering the total power unit price. Can be done.

Although the number of generators in each embodiment was two, the present invention can be similarly applied to the case where the number of generators is three or more.

[0061]

As described above, according to the first and fourth aspects of the invention, when the power load increases or decreases, the difference between the power purchase unit price and the predicted power generation unit price at that time is reflected. The amount of power purchased is increased and the number of operating vehicles is maintained or reduced. As a result, it is possible to realize the minimum operating condition of the total power unit price.

According to the second and fifth aspects of the present invention, when it is found in the future that the power load will decrease, the power purchase amount is increased in advance while the operating number is decreased. As a result, low load operation can be avoided, and the operation state of the minimum unit price of total power can be realized.

Further, according to the inventions of claims 3 and 6, when a future prediction is made and it is predicted that the power load sharply decreases, the amount of received power is increased to avoid reverse power flow, and normally the minimum received power is received. The quantity is lowered. As a result, it is possible to realize the operation state of the minimum total power unit price.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a flowchart showing a processing procedure of the first embodiment of the present invention.

FIG. 3 is a case where the operation control method of the first embodiment of the present invention is applied to a private power generation system with two 1,000 kW generators (right side) and a case where a conventional operation control method is applied (left side). FIG. 3 is an explanatory diagram showing the respective power generation states of FIG.

FIG. 4 is a flowchart showing a processing procedure according to a second embodiment of the present invention.

FIG. 5 shows a case where the operation control method according to the second embodiment of the present invention is applied to a private power generation system with two 1,000 kW generators (right side) and a case where a conventional operation control method is applied (left side). FIG. 3 is an explanatory diagram showing the respective power generation states of FIG.

FIG. 6 is a flowchart showing a processing procedure of a third embodiment of the present invention.

FIG. 7 shows a case where the operation control method of the third embodiment of the present invention is applied (right side) and a case where a conventional operation control method is applied (left side) to a private power generation system with two 1,000 kW generators. FIG. 3 is an explanatory diagram showing the respective power generation states of FIG.

FIG. 8 is a building front vertical cross-sectional view showing a basic configuration example of a diesel cogeneration system.

FIG. 9 is a side elevational sectional view of a building showing a basic configuration example of a diesel cogeneration system.

FIG. 10 is a flowchart showing a basic flow of exhaust heat, electric power, etc. of the diesel cogeneration system.

[Fig. 11] Basic power generation of a conventional private power generation system
An example of the power purchase situation is shown, (A) shows the case where the power load is constant,
FIG. 7B is an explanatory diagram showing an example of the power generation / power purchase status in the case of a Yamagata power load, and FIG.

FIG. 12 is an explanatory diagram showing an example of a power generation state of each generator in a conventional operation control method for a private power generation system.

FIG. 13 is a flowchart showing a processing procedure when the conventional power generation system for electric power generation rises.

FIG. 14 is a flowchart showing a processing procedure when the power purchase for the conventional private power generation system is reduced.

[Explanation of symbols]

1 Main fuel tank 2 small fuel tank 3 engine 4 generator 5 Primary cooling water 6 heat exchanger 7 hot water 8 Steam exhaust gas boiler 9 steam 10 silencer 11 chimney 12 Other heat exchangers 13 Cooling tower 14 Operation control unit 15 Power generation status 16 Power Purchase Status 17 Power load 18 1st unit operation status 19 Operation status of the second unit 20 Example of conventional power generation during lunch break 21 Example of power generation status before noon in the third embodiment 22 Example of power generation status during lunch break in the third embodiment 23 Example of power generation status in the morning in the third embodiment 24 Example of afternoon power generation status in the third embodiment 54 Operation control device

Claims (6)

[Claims] 1. An operation control method for an in-house power generation system having a plurality of generators, wherein increasing the number of generators results in a low load, or when each generator currently generating electricity becomes a low load. Compare the unit electricity purchase price at that time with the estimated electricity generation unit price, and if the electricity purchase unit price is cheaper, increase the amount of electricity purchased and either keep the number of generators small or reduce the number of generators. An operation control method for a private power generation system, which is characterized by: 2. An operation control method for a private power generation system having a plurality of generators, wherein a daily power load is input in advance, and a decrease in the power load is predicted by a power load prediction based on the daily power load. In addition, the operation control method of the private power generation system, comprising increasing the amount of power purchased before the predicted reduction of the electric power load and decreasing the number of operating generators. 3. An operation control method for a private power generation system having a plurality of generators, wherein an electric power daily load is input in advance, and a sudden decrease of the electric power load is predicted by an electric power load prediction based on the electric power daily load. In the case of the above, the amount of electric power to be purchased is increased and the number of operating generators is decreased before the predicted abrupt decrease of the electric power load even if the reverse power flow does not occur due to the abrupt decrease of the electric power load. And, usually, the minimum amount of power received is lowered, and the operation control method of the private power generation system is characterized. 4. An operation control device for a private power generation system having a plurality of generators, a monitoring means for monitoring an electric power load and the number of generators operating, and a case where the number of generators is reduced to a low load or present power generation. When the load on each generator is low, the unit price comparison means for comparing the unit purchase price of commercial power and the predicted unit price of the generator at that time, and the comparison result shows that If it is cheaper, it is equipped with a control means for controlling the number of generators, either by increasing the power purchase amount and keeping the number of generators small or reducing the number of generators. Operation control device for private power generation system. 5. In an operation control device of a private power generation system having a plurality of generators, a prediction means for predicting an electric power load based on a previously input daily electric power load, and a result of the prediction that a decrease in the electric power load is predicted. Control unit that controls the number of electric generators that increase the amount of power purchased before the predicted decrease in the electric power load and decreases the number of operating generators when the electric power generation is predicted. System operation control device. 6. An operation control device for a private power generation system having a plurality of generators, a predicting means for predicting an electric power load based on a pre-input daily electric power load, and a result of the prediction, a rapid decrease in the electric power load. When the predicted power load is decreased, the amount of power purchased is increased to the point where a reverse power flow does not occur due to the sudden decrease in the power load, and the number of operating generators is increased. An operation control device for an in-house power generation system, comprising: