Power generation system and power generation controller

Abstract

To provide a power generation system and a power generation controller which can cause a hydroelectric generator to function as a primary adjusting force.SOLUTION: A power generation controller 4 executes discharge control of controlling an alkaline storage battery 3 to discharge power in a power net 5 when the power net 5 is running out of power, and starts power increase control of controlling at least a hydroelectric generator of a hydro power plant 2c to increase the power generation while the alkaline storage battery 3 is discharging power to the power net 5.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a power generation system and a power generation control device.

Background Art

[0002] Conventionally, a power generation system including a renewable energy generator, a storage battery, a renewable energy power generation prediction unit that predicts a renewable energy power generation possible value, a power trading information receiving unit that receives power trading information, and a storage battery control calculation unit that calculates command values for power trading power generation, renewable energy power generation, and storage battery charge / discharge from the renewable energy power generation prediction amount predicted by the renewable energy power generation prediction unit and the power trading information, and a power converter that distributes power according to the power trading power generation and the renewable energy power generation has been proposed in Patent Document 1.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the case where a hydraulic generator is applied as the renewable energy generator in the above-described conventional power generation system, the power generated cannot be instantaneously increased, so there is a problem that it cannot function as a primary regulation force with a response time within 10 seconds and a continuous time of 5 minutes or more as an adjustment force for coping with intra-hour fluctuations (ultra-short cycle components) and power source dropout.

[0005] The present invention has been made to solve the above problems, and an object thereof is to provide a power generation system and a power generation control device that can cause a hydraulic generator to function as a primary regulation force.

Means for Solving the Problems

[0006] The power generation system according to the present invention includes a hydraulic generator, a hydroelectric power plant capable of supplying power from the hydraulic generator to the power grid, a power storage device that can be charged from the power grid and discharge the charged power to the power grid, and a power generation control device that controls the hydraulic generator and the power storage device. When the power of the power grid is insufficient, the power generation control device executes discharge control to control the power storage device to discharge power to the power grid, and starts power increase control to control the hydraulic generator to increase the generated power during the period when power is being discharged from the power storage device to the power grid.

Effects of the Invention

[0007] The present invention can provide a power generation system and a power generation control device that can make a hydraulic generator function as a primary regulating force.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0010] [First Embodiment] As shown in FIG. 1, the power generation system 1 includes a plurality of hydroelectric power plants 2a to 2c, an alkaline storage battery 3, and a power generation control device 4. Although three hydroelectric power plants 2a to 2c are shown in FIG. 1, the number of hydroelectric power plants included in the power generation system according to the present invention is not limited.

[0011] Each of the hydroelectric power plants 2a to 2c is provided so as to be able to supply the generated electric power to the power grid 5. The alkaline storage battery 3 constitutes a power storage device and is, for example, a nickel-metal hydride battery. The alkaline storage battery 3 is provided so as to be chargeable from the power grid 5 and to be able to discharge the stored electric power to the power grid 5.

[0012] Each of the hydroelectric power plants 2a to 2c is constituted by a run-of-river power plant without a water storage dam. The hydroelectric power plants 2a to 2c are provided in series so as to form one water flow path 6. In FIG. 1, the water flowing in from the river 7 via the intake weir 8 passes through the hydroelectric power plant 2a, the hydroelectric power plant 2b, and the hydroelectric power plant 2c in sequence and returns to the river 7.

[0013] As shown in FIG. 2, each of the hydroelectric power plants 2a to 2c (hereinafter also collectively referred to as "hydroelectric power plant 2") has a water storage tank 10 and a hydroelectric generator 11. Water is supplied to the water storage tank 10 from the upstream side of the flow path 6. The water storage tank 10 stores water to be supplied to the hydroelectric generator 11.

[0014] The water storage tank 10 is composed of a sedimentation tank that removes impurities such as mud from the water supplied from the flow path 6, an upper water tank that stabilizes the water pressure of the water supplied from the flow path 6, a water conduit that operates at the same water surface as the upper water tank, or other tanks or ponds that store water. The water storage tank 10 is provided with a water level gauge 21 for detecting the water level of the water stored in the water storage tank 10.

[0015] The hydroelectric generator 11 has a water turbine 22 and a generator 23. The water turbine 22 generates a rotational force corresponding to the flow rate of the water supplied from the water storage tank 10. The generator 23 converts the rotational force generated by the water turbine 22 into electric power. The water supplied from the water storage tank 10 to the hydroelectric generator 11 is discharged from the hydroelectric generator 11 to the downstream side of the flow path 6.

[0016] In the present embodiment, the water turbine 22 is constituted by a Francis turbine. The water turbine 22 has a guide vane 31 and an actuator 32. The actuator 32 adjusts the opening degree of the guide vane 31 between the closed state and the open state.

[0017] When the guide vane 31 is in the open state, the flow rate of the water supplied from the water storage tank 10 to the water turbine 22 becomes the largest. For this reason, the rotational force generated by the water turbine 22 becomes the maximum, and the generated electric power of the generator 23 becomes the rated electric power.

[0018] When the guide vane 31 is in the closed state, the flow rate of the water supplied from the water storage tank 10 to the water turbine 22 becomes about 3% as compared with the case where the guide vane 31 is in the open state. As a result, the generated electric power of the generator 23 decreases to the minimum electric power that can be generated.

[0019] Figure 3 shows the relationship between the opening degree of the guide vane 31 and the output power of the hydraulic generator 11. The opening degree A corresponds to the opening degree in the open state. When the opening degree of the guide vane 31 is the opening degree A, the rated power is output from the hydraulic generator 11.

[0020] The opening degree B corresponds to the opening degree during normal power generation when the hydraulic generator 11 generates power according to the flow rate of the water supplied to the water storage tank 10. During normal power generation, the guide vane 31 is controlled by the power generation control device 4 so that the water level of the water storage tank 10 becomes constant (corresponding to "target value 1" shown in Fig. 5).

[0021] Therefore, when the opening degree of the guide vane 31 is the opening degree B, water with the same flow rate as the water supplied to the water storage tank 10 is supplied to the hydraulic generator 11. Therefore, when the opening degree of the guide vane 31 is the opening degree B, the normal power generation power corresponding to the flow rate of the water supplied to the water storage tank 10 is output from the hydraulic generator 11.

[0022] The flow rate of the water supplied to the water storage tank 10 depends on the flow rate of the river 7 and is affected by seasons and rainfall. For this reason, the opening degree B is not a constant value and varies according to the flow rate of the water supplied to the water storage tank 10.

[0023] The opening degree C corresponds to the opening degree during the adjustment force supply when the power generation system 1 supplies the adjustment force to the power grid 5. When the opening degree of the guide vane 31 is the opening degree C, in addition to the water supplied to the water storage tank 10, the water stored in the water storage tank 10 is supplied to the hydraulic generator 11.

[0024] Therefore, when the opening degree of the guide vane 31 is the opening degree C, water with a flow rate larger than the flow rate of the water supplied to the water storage tank 10 is supplied to the hydraulic generator 11. For this reason, when the opening degree of the guide vane 31 is the opening degree C, the power during adjustment force supply, which is the sum of the normal power generation power corresponding to the flow rate of the water supplied to the water storage tank 10 and the adjustment power Pm corresponding to the decrease amount of the water stored in the water storage tank 10, is output from the hydraulic generator 11.

[0025] The power generation system 1 supplies the regulating power to the power grid 5 by the discharge power of the alkaline storage battery 3 and the regulating power Pm of the hydraulic generators 11 of the respective hydroelectric power plants 2a to 2c. When the sum of the normal power generation power and the regulating power Pm becomes the rated power, the opening C becomes equal to the opening A.

[0026] The opening D corresponds to the opening at the time of restoring the water level of the water storage tank 10. The opening D is set to be larger than the opening E corresponding to the closed state opening and smaller than the opening B. When the opening of the guide vane 31 is the opening D, water with a flow rate less than the water supplied to the water storage tank 10 is supplied to the hydraulic generator 11.

[0027] Therefore, if the flow rate of water supplied to the water storage tank 10 is the same during normal power generation and during water level recovery, when the opening of the guide vane 31 is the opening D, during water level recovery, the water level recovery power lower than the normal power generation power is output from the hydraulic generator 11.

[0028] In FIG. 1, the power generation control device 4 is constituted by a computer device including a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory for storing backup data and the like, an input port, and an output port.

[0029] In the ROM of this computer unit, a program for causing the computer unit to function as the power generation control device 4 is stored together with various constants and the like. That is, when the CPU executes the program stored in the ROM using the RAM as a work area, this computer unit functions as the power generation control device 4 in the present embodiment.

[0030] As shown in Fig. 4, various sensors including a water level gauge 21 (hereinafter also referred to as "water level gauge 21a", "water level gauge 21b", and "water level gauge 21c" respectively) provided in the water storage tanks 10 of each of the hydroelectric power plants 2a to 2c, a SOC sensor 41 for detecting the state of charge (hereinafter also referred to as "SOC") of the alkaline storage battery 3, and a frequency sensor 42 for detecting the power grid frequency of the power grid 5 are directly or connected via a communication line to the input port of the power generation control device 4.

[0031] To the output port of the power generation control device 4, various control objects including an actuator 32 (hereinafter also referred to as "actuator 32a", "actuator 32b", and "actuator 32c" respectively) provided in the water turbines 22 of each of the hydroelectric power plants 2a to 2c and an inverter 43 provided on the power grid 5 side of the alkaline storage battery 3 are directly or connected via a communication line. The power generation control device 4 controls various control objects connected to the output port based on the information obtained from the various sensors connected to the input port.

[0032] As shown in Fig. 5, target values 1 to 3 are set for the water levels of the water storage tanks 10 of each of the hydroelectric power plants 2a to 2c in the power generation control device 4. The target value 1 represents the target water level during normal power generation. During normal power generation, the power generation control device 4 controls the opening degree of the guide vane 31 so that the water levels of the water storage tanks 10 of each of the hydroelectric power plants 2a to 2c maintain the target value 1, using the water levels detected by the water level gauges 21a to 21c as feedback values.

[0033] The target value 2 represents the lower limit water level during normal power generation. Therefore, the target value 2 is less than or equal to the target value 1 and becomes the target water level during water level recovery. The target value 3 represents the lower limit water level during adjustment power supply when the adjustment power generation is output from the hydroelectric generator 11. Therefore, the target value 3 is less than the target value 2 and is greater than or equal to the lower limit value for preventing air entrainment in the water supplied to the hydroelectric generator 11, and becomes the target water level during adjustment power supply.

[0034] The operation of the power generation control device 4 in the power generation system 1 configured as described above will be described with reference to Figs. 6 to 7.

[0035] As shown in FIG. 6, the power generation control device 4 controls the alkaline storage battery 3 in three battery control modes: a normal battery mode, a regulating power output mode, and an SOC recovery mode. Normally, the power generation control device 4 controls the alkaline storage battery 3 in the normal battery mode.

[0036] <Normal battery mode> In the normal battery mode, the alkaline storage battery 3 is charged to a predetermined charge rate such that the alkaline storage battery 3 does not become overcharged. In the normal battery mode, the power generation control device 4 controls the inverter 43 so as to prohibit discharging power from the alkaline storage battery 3 to the power grid 5 and charging the alkaline storage battery 3 from the power grid 5.

[0037] In the normal battery mode, when the power of the power grid 5 is insufficient, the power generation control device 4 shifts the battery control mode to the regulating power output mode. The power generation control device 4 determines that the power of the power grid 5 is insufficient when the frequency detected by the frequency sensor 42 drops outside the allowable range.

[0038] <Regulating power output mode> In the regulating power output mode, the power generation control device 4 controls the inverter 43 so that the power corresponding to the regulating power of the power generation system 1 is discharged from the alkaline storage battery 3 to the power grid 5. Thus, in the regulating power output mode, the power generation control device 4 executes discharge control for controlling the alkaline storage battery 3 to discharge power to the power grid 5.

[0039] In the regulating power output mode, when the sum of the regulating powers Pm of the hydraulic generators 11 of the respective hydroelectric power plants 2a to 2c becomes equal to or greater than the regulating power of the power generation system 1, the power generation control device 4 shifts the battery control mode to the SOC recovery mode.

[0040] <SOC recovery mode> In the SOC recovery mode, the power generation control device 4 controls the inverter 43 so that the alkaline storage battery 3 is charged from the power grid 5. When the SOC detected by the SOC sensor 41 becomes equal to or higher than a predetermined charging rate in the SOC recovery mode, the power generation control device 4 shifts the battery control mode to the normal battery mode. The predetermined charging rate is set to such an extent that the power corresponding to the regulating power of the power generation system 1 can be discharged from the alkaline storage battery 3 to the power grid 5 for a certain period of time (for example, 5 minutes) or longer.

[0041] Note that since the SOC of the alkaline storage battery 3 may decrease due to self-discharge, in the normal battery mode, when the SOC detected by the SOC sensor 41 decreases beyond the allowable range from the predetermined charging rate, the power generation control device 4 shifts the battery control mode to the SOC recovery mode.

[0042] As shown in FIG. 7, the power generation control device 4 individually controls the hydraulic generators 11 of the respective hydroelectric power plants 2a to 2c in three hydraulic control modes: the normal hydraulic mode, the regulating hydraulic mode, and the water level recovery mode. Ordinarily, the power generation control device 4 controls the hydraulic generator 11 in the normal hydraulic mode.

[0043] <Normal Hydraulic Mode> In the normal hydraulic mode, the power generation control device 4 controls the actuator 32 so that the opening degree of the guide vane 31 provided in the hydraulic generator 11 becomes the opening degree B (see FIG. 3) during normal power generation. That is, in the normal hydraulic mode, the power generation control device 4 controls the actuator 32 so that the water level of the water storage tank 10 maintains the target value 1 (see FIG. 5). Therefore, in the normal hydraulic mode, the normal power generation power is supplied from the hydraulic generator 11 to the power grid 5.

[0044] In the normal hydraulic mode, when the battery control mode is the regulating power output mode and the SOC detected by the SOC sensor 41 becomes equal to or lower than the threshold value THc, the power generation control device 4 shifts the hydraulic control mode to the regulating hydraulic mode. The threshold value THc is set to the charging rate at which the discharge power of the alkaline storage battery 3 begins to decrease.

[0045] In this way, the power generation control device 4 in the present embodiment shifts the hydraulic control mode for the hydraulic generators 11 of the hydroelectric power plants 2a to 2c from the normal hydraulic mode to the adjusted hydraulic mode based on the same transition conditions. That is, in the present embodiment, the hydraulic control modes for the hydraulic generators 11 of the hydroelectric power plants 2a to 2c simultaneously shift from the normal hydraulic mode to the adjusted hydraulic mode.

[0046] <Adjusted Hydraulic Mode> In the adjusted hydraulic mode, the power generation control device 4 controls the actuator 32 so that the opening degree of the guide vane 31 provided in the hydraulic generator 11 becomes the opening degree C (see FIG. 3) at the time of supplying the adjustment force. That is, in the adjusted hydraulic mode, the power generation control device 4 controls the actuator 32 so that the water level of the water storage tank 10 becomes the target value 3 (see FIG. 5).

[0047] Therefore, in the adjusted hydraulic mode, when the opening degree of the guide vane 31 provided in the hydraulic generator 11 becomes the opening degree C (see FIG. 3), the power at the time of supplying the adjustment force, which is the sum of the normal generated power and the adjustment power Pm, is supplied from the hydraulic generator 11 to the power grid 5. In this way, in the adjusted hydraulic mode, the power generation control device 4 executes an increased power control for controlling the hydraulic generator 11 so as to increase the generated power from the normal generated power.

[0048] In the adjusted hydraulic mode, when the water level detected by the water level gauge 21 becomes equal to or lower than the target value 3 (see FIG. 5), the power generation control device 4 shifts the hydraulic control mode to the water level recovery mode.

[0049] <Water Level Recovery Mode> In the water level recovery mode, the power generation control device 4 controls the actuator 32 so that the opening degree of the guide vane 31 provided in the hydraulic generator 11 becomes the opening degree D (see FIG. 3) at the time of water level recovery. That is, in the water level recovery mode, the power generation control device 4 controls the actuator 32 so that the water level of the water storage tank 10 becomes the target value 2 (see FIG. 5).

[0050] Therefore, in the water level recovery mode, when the opening degree of the guide vane 31 provided in the hydraulic generator 11 reaches the opening degree D (see FIG. 3), the power during water level recovery is supplied from the hydraulic generator 11 to the power grid 5. In the water level recovery mode, when the water level detected by the water level gauge 21 becomes equal to or higher than the target value 2 (see FIG. 5), the power generation control device 4 shifts the hydraulic control mode to the normal hydraulic mode.

[0051] The regulating power output by the power generation system 1 described above will be described with reference to FIG. 8. FIG. 8 shows the transition of the discharge power Pc of the alkaline storage battery 3 and the regulating power Pm of the hydraulic generators 11 of each of the hydroelectric power plants 2a to 2c (hereinafter also referred to as "regulating power Pm1", "regulating power Pm2", and "regulating power Pm3").

[0052] When it is determined at time 0 by the power generation control device 4 that the power of the power grid 5 is insufficient, the battery control mode shifts from the normal battery mode to the regulating power output mode, and the discharge control is executed by the power generation control device 4.

[0053] Therefore, at time 0, discharging starts from the alkaline storage battery 3 to the power grid 5, and at time t1 (0.1 seconds later in the figure), the regulating power of the power generation system 1 is supplied from the alkaline storage battery 3 to the power grid 5.

[0054] When the SOC detected by the SOC sensor 41 becomes equal to or lower than the threshold value THc at time t2, the hydraulic control mode for the hydraulic generators 11 of each of the hydroelectric power plants 2a to 2c shifts from the normal hydraulic mode to the regulating hydraulic mode.

[0055] For this reason, the power generation control device 4 executes power increase control for the hydraulic generators 11 of each of the hydroelectric power plants 2a to 2c. Therefore, at time t2, the actuators 32a to 32c are controlled so that the opening degree of the guide vane 31 of the hydraulic generators 11 of each of the hydroelectric power plants 2a to 2c changes from the opening degree B to the opening degree C (see FIG. 3), and the regulating powers Pm1 to Pm3 supplied from the hydraulic generators 11 of each of the hydroelectric power plants 2a to 2c to the power grid 5 increase.

[0056] At time t3 (60 seconds later in the figure), when the opening degree of the guide vane 31 of the hydraulic generator 11 of each of the hydroelectric power plants 2a to 2c reaches the opening degree C (see FIG. 3), the sum of the regulating powers Pm1 to Pm3 supplied from the hydraulic generators 11 of the hydroelectric power plants 2a to 2c to the power grid 5 becomes the regulating power of the power generation system 1, and since the battery control mode shifts from the regulating power output mode to the SOC recovery mode, the discharge power Pc of the alkaline storage battery 3 becomes zero.

[0057] At time t4 (6 minutes later in the figure), when the water level detected by the water level gauge 21a provided in the water storage tank 10 of the uppermost upstream hydroelectric power plant 2a in the flow path 6 reaches the target value 3 (see FIG. 5), the hydraulic control mode for the hydraulic generator 11 of the hydroelectric power plant 2a shifts from the regulating water power mode to the water level recovery mode.

[0058] Therefore, the actuator 32a is controlled so that the opening degree of the guide vane 31 of the hydraulic generator 11 of the hydroelectric power plant 2a changes from the opening degree C to the opening degree D (see FIG. 3), and the regulating power Pm1 supplied from the hydraulic generator 11 of the hydroelectric power plant 2a to the power grid 5 decreases.

[0059] At time t5 (8 minutes later in the figure), when the water level detected by the water level gauge 21b provided in the water storage tank 10 of the hydroelectric power plant 2b on the downstream side of the flow path 6 with respect to the hydroelectric power plant 2a reaches the target value 3 (see FIG. 5), the hydraulic control mode for the hydraulic generator 11 of the hydroelectric power plant 2b shifts from the regulating water power mode to the water level recovery mode.

[0060] Therefore, the actuator 32b is controlled so that the opening degree of the guide vane 31 of the hydraulic generator 11 of the hydroelectric power plant 2b changes from the opening degree C to the opening degree D (see FIG. 3), and the regulating power Pm2 supplied from the hydraulic generator 11 of the hydroelectric power plant 2b to the power grid 5 decreases.

[0061] At time t6 (10 minutes later in the figure), when the water level detected by the water level gauge 21c provided in the water storage tank 10 of the hydroelectric power plant 2c on the downstream side of the flow path 6 with respect to the hydroelectric power plant 2b reaches the target value 3 (see FIG. 5), the hydraulic control mode for the hydraulic generator 11 of the hydroelectric power plant 2c shifts from the adjusted hydraulic mode to the water level recovery mode.

[0062] For this reason, the actuator 32c is controlled so that the opening degree of the guide vane 31 of the hydraulic generator 11 of the hydroelectric power plant 2c changes from the opening degree C to the opening degree D (see FIG. 3), and the regulated power Pm3 supplied from the hydraulic generator 11 of the hydroelectric power plant 2c to the power grid 5 decreases.

[0063] During the period when the hydraulic control mode for the hydraulic generator 11 of the hydroelectric power plant 2a is the adjusted hydraulic mode, since the water stored in the water storage tank 10 of the hydroelectric power plant 2a is discharged to the downstream side of the flow path 6, the flow rate of the water supplied to the water storage tank 10 of the hydroelectric power plant 2b increases.

[0064] For this reason, after the hydraulic control mode for the hydraulic generator 11 of the hydroelectric power plant 2a shifts from the adjusted hydraulic mode to the water level recovery mode, the hydraulic control mode for the hydraulic generator 11 of the hydroelectric power plant 2b shifts from the adjusted hydraulic mode to the water level recovery mode.

[0065] Also, during the period when the hydraulic control mode for the hydraulic generator 11 of the hydroelectric power plant 2a is the adjusted hydraulic mode, since the water stored in the water storage tank 10 of the hydroelectric power plant 2a is discharged to the downstream side of the flow path 6, the flow rate of the water supplied to the water storage tank 10 of the hydroelectric power plant 2c increases.

[0066] Furthermore, during the period when the hydraulic control mode for the hydraulic generator 11 of the hydroelectric power plant 2b is the adjusted hydraulic mode, since the water stored in the water storage tank 10 of the hydroelectric power plant 2b is discharged to the downstream side of the flow path 6, the flow rate of the water supplied to the water storage tank 10 of the hydroelectric power plant 2c increases.

[0067] Therefore, after the hydraulic control mode for the hydraulic generator 11 of the hydroelectric power plant 2b shifts from the adjusted hydraulic mode to the water level recovery mode, the hydraulic control mode for the hydraulic generator 11 of the hydroelectric power plant 2c shifts from the adjusted hydraulic mode to the water level recovery mode.

[0068] Thus, during the period from time t1 to time t2, the regulating power of the power generation system 1 is supplied to the power grid 5 by the discharge power Pc of the alkaline storage battery 3. Also, during the period from time t2 to time t3, the regulating power of the power generation system 1 is supplied to the power grid 5 by the sum of the discharge power Pc of the alkaline storage battery 3 and the regulating powers Pm1 to Pm3 of the hydraulic generators 11 of the hydroelectric power plants 2a to 2c. Further, during the period from time t3 to time t4, the regulating power of the power generation system 1 is supplied to the power grid 5 by the sum of the regulating powers Pm1 to Pm3 of the hydraulic generators 11 of the hydroelectric power plants 2a to 2c.

[0069] <Operational Effect> As described above, since the power generation system 1 according to the present embodiment can supply a primary regulating power within a response time of 10 seconds and a duration of 5 minutes or more to the power grid 5, the hydraulic generator 11 can function as a primary regulating power.

[0070] Also, the power generation system 1 according to the present embodiment constitutes a power storage device with an alkaline storage battery 3 having good startup characteristics, and when the power of the power grid 5 is insufficient, it starts discharge control to discharge the power charged in the alkaline storage battery 3 to the power grid 5, so that the responsiveness when the power grid 5 is short of power can be increased.

[0071] Since the alkaline storage battery 3 of the power generation system 1 according to the present embodiment can instantaneously discharge a large current, when the power of the power grid 5 is insufficient, a power shortage of the power grid 5 such as a blackout can be instantaneously eliminated.

[0072] Further, in order to start the power increase control for the hydroelectric power plants 2a to 2c during the period when power is discharged from the alkaline storage battery 3 to the power grid 5, before the power stored in the alkaline storage battery 3 is consumed, power is supplied from the hydroelectric generators 11 of the hydroelectric power plants 2a to 2c to the power grid 5. For this reason, the power generation system 1 according to the present embodiment can continuously supply stable power to the power grid 5 and can eliminate the power shortage in the power grid 5.

[0073] In addition, since the power generation system 1 according to the present embodiment simultaneously increases the generated power by the hydroelectric generators 11 of the hydroelectric power plants 2a to 2c by the power increase control, a large amount of power can be supplied to the power grid 5.

[0074] In addition, in the power generation system 1 according to the present embodiment, a water storage tank 10 is provided in each of the hydroelectric power plants 2a to 2c, and in order to increase the generated power of the hydroelectric generator 11 using the water stored in the water storage tank 10, even if each of the hydroelectric power plants 2a to 2c is a run-of-river power plant without a water storage dam, when the power in the power grid 5 is insufficient, power can be supplied to the power grid 5.

[0075] <Modification Example> In the present embodiment, an example in which the water turbine 22 is configured by a Francis turbine has been described. On the other hand, the water turbine 22 may be configured by a water turbine other than a Francis turbine as long as it can adjust the flow rate of water supplied from the water storage tank 10 to the water turbine 22. For example, the water turbine 22 may be configured by another reaction turbine such as a Kaplan turbine, or may be configured by an impulse turbine such as a Pelton turbine.

[0076] In addition, in the present embodiment, an example in which the adjustment power of the power generation system 1 is supplied to the power grid 5 by the sum of the discharge power Pc of the alkaline storage battery 3 and the adjustment powers Pm1 to Pm3 of the hydroelectric generators 11 of the hydroelectric power plants 2a to 2c has been described.

[0077] On the other hand, when the power generation system 1 according to the present embodiment can output the adjustment power of the power generation system 1 by one of the hydraulic generators 11 of the hydraulic power plants 2a to 2c (for example, the hydraulic generator 11 of the hydraulic power plant 2a), the adjustment power of the power generation system 1 may be supplied to the power grid 5 by the sum of the discharge power Pc of the alkaline storage battery 3 and the adjustment power Pm of this one hydraulic generator 11.

[0078] Further, when the power generation system 1 according to the present embodiment can output the adjustment power of the power generation system 1 by two of the hydraulic generators 11 of the hydraulic power plants 2a to 2c (for example, the hydraulic generators 11 of the hydraulic power plants 2a and 2b), the adjustment power of the power generation system 1 may be supplied to the power grid 5 by the sum of the discharge power Pc of the alkaline storage battery 3 and the adjustment power Pm of these two hydraulic generators 11.

[0079] Also, in the present embodiment, as described with reference to FIG. 6, an example in which the power generation control device 4 shifts the battery control mode to the SOC recovery mode when the sum of the adjustment powers Pm of the hydraulic generators 11 of the respective hydraulic power plants 2a to 2c becomes the adjustment power of the power generation system 1 in the adjustment power output mode has been described.

[0080] On the other hand, when the sum of the adjustment powers Pm of the hydraulic generators 11 of the respective hydraulic power plants 2a to 2c becomes the adjustment power of the power generation system 1 in the adjustment power output mode, the power generation control device 4 controls the inverter 43 to prohibit discharging from the alkaline storage battery 3 to the power grid 5, and after a certain period of time (for example, 5 hours) has elapsed, the battery control mode may be shifted to the SOC recovery mode.

[0081] Further, in the regulating power output mode, when the sum of the regulating powers Pm of the hydraulic generators 11 of the respective hydroelectric power plants 2a to 2c becomes the regulating power of the power generation system 1, the power generation control device 4 controls the inverter 43 to prohibit discharging from the alkaline storage battery 3 to the power grid 5. When it is determined that the power of the power grid 5 has become excessive, the battery control mode may be shifted to the SOC recovery mode. In this case, when the frequency detected by the frequency sensor 42 rises outside the allowable range, the power generation control device 4 determines that the power of the power grid 5 has become excessive.

[0082] Further, when the power generation control device 4 determines that the power of the power grid 5 has become excessive, the target value 1 (see FIG. 5) for the water storage tanks 10 of the respective hydroelectric power plants 2a to 2c may be increased to reduce the power supplied from the respective hydroelectric power plants 2a to 2c to the power grid 5.

[0083] Also, in the present embodiment, as described with reference to FIG. 7, in the normal hydraulic mode, when the battery control mode is the regulating power output mode and the SOC detected by the SOC sensor 41 becomes equal to or less than the threshold value THc, the power generation control device 4 shifts the hydraulic control mode for the hydraulic generators 11 of the respective hydroelectric power plants 2a to 2c to the regulating hydraulic mode. An example has been described.

[0084] On the other hand, as long as the battery control mode is the regulating power output mode, the power generation control device 4 may change the transition condition for shifting the hydraulic control mode for the hydraulic generators 11 of the hydroelectric power plants 2a to 2c from the normal hydraulic mode to the regulating hydraulic mode.

[0085] For example, when a certain time (for example, 1 minute) has elapsed since the battery control mode became the regulating power output mode, the power generation control device 4 may shift the hydraulic control mode for the hydraulic generators 11 of the hydroelectric power plants 2a to 2c from the normal hydraulic mode to the regulating hydraulic mode.

[0086] In addition, in the present embodiment, an example in which the hydroelectric power plants 2a to 2c are provided in series so as to form one water flow path 6 has been described. On the other hand, the hydroelectric power plants 2a to 2c in the present embodiment may be provided in parallel so as to form separate flow paths from each other.

[0087] For example, in FIG. 1, the water that has flowed in from the river 7 via the intake weir 8 returns to the river 7 via the hydroelectric power plant 2a, and the water that has flowed in from the river 7 via the first other intake weir returns to the river 7 via the hydroelectric power plant 2b. The water that has flowed in from the river 7 via the second other intake weir may return to the river 7 via the hydroelectric power plant 2c.

[0088] In addition, in the present embodiment, an example in which each of the hydroelectric power plants 2a to 2c is configured by a run-of-river power plant without a storage dam has been described, but each of the hydroelectric power plants 2a to 2c may be configured by a dam-type power plant. When each of the hydroelectric power plants 2a to 2c is configured by a dam-type power plant, the water storage tank 10 is configured by a dam lake.

[0089] [Second Embodiment] Regarding the second embodiment of the present invention described below, the differences from the first embodiment of the present invention will be described.

[0090] Compared with the first embodiment of the present invention, in the present embodiment, for the state transition of the hydraulic control mode described with reference to FIG. 7, the transition conditions for shifting the hydraulic control mode of the hydraulic generators 11 of each of the hydroelectric power plants 2a and 2b, excluding the hydroelectric power plant 2c, which is the most downstream hydroelectric power plant of the flow path 6 among the hydroelectric power plants 2a to 2c, from the normal hydraulic mode to the adjusted hydraulic mode are different.

[0091] Note that the transition conditions for shifting the hydraulic control mode of the hydraulic generator 11 of the hydroelectric power plant 2c from the normal hydraulic mode to the adjusted hydraulic mode are as described with reference to FIG. 7 for the first embodiment of the present invention.

[0092] As shown in FIG. 9, when the hydraulic control mode for the hydraulic generator 11 of the hydroelectric power plant 2b is the normal hydraulic mode in this embodiment, if the water level detected by the water level gauge 21a provided in the water storage tank 10 of the hydroelectric power plant 2c on the downstream side of the flow path 6 with respect to the hydroelectric power plant 2b becomes equal to or lower than the target value 3 (see FIG. 5, corresponding to the "predetermined value" in the present invention), the hydraulic control mode for the hydraulic generator 11 of the hydroelectric power plant 2b is shifted to the adjusted hydraulic mode.

[0093] Further, in this embodiment, when the hydraulic control mode for the hydraulic generator 11 of the hydroelectric power plant 2a is the normal hydraulic mode, if the water level detected by the water level gauge 21b provided in the water storage tank 10 of the hydroelectric power plant 2b on the downstream side of the flow path 6 with respect to the hydroelectric power plant 2a becomes equal to or lower than the target value 3 (see FIG. 5, corresponding to the "predetermined value" in the present invention), the hydraulic control mode for the hydraulic generator 11 of the hydroelectric power plant 2a is shifted to the adjusted hydraulic mode.

[0094] Regarding the regulating force output by the power generation system 1 described above, it will be described with reference to FIG. 10. FIG. 10 shows the transitions of the discharge power Pc of the alkaline storage battery 3 and the regulating powers Pm1 to Pm3 of the hydraulic generators 11 of the respective hydroelectric power plants 2a to 2c.

[0095] When it is determined at time 0 by the power generation control device 4 that the power of the power grid 5 is insufficient, the battery control mode shifts from the normal battery mode to the regulating force output mode, and the discharge control is executed by the power generation control device 4.

[0096] Therefore, at time 0, discharging starts from the alkaline storage battery 3 to the power grid 5, and at time t11 (0.1 second later in the figure), the regulating force of the power generation system 1 is supplied from the alkaline storage battery 3 to the power grid 5.

[0097] When the SOC detected by the SOC sensor 41 becomes equal to or lower than the threshold value THc at time t12, the hydraulic control mode for the hydraulic generator 11 of the hydroelectric power plant 2c shifts from the normal hydraulic mode to the adjusted hydraulic mode.

[0098] Therefore, the power increase control for the hydraulic generator 11 of the hydroelectric power plant 2c is executed by the power generation control device 4. Accordingly, at time t12, the actuator 32c is controlled so that the opening degree of the guide vane 31 of the hydraulic generator 11 of the hydroelectric power plant 2c changes from the opening degree B to the opening degree C (see FIG. 3), and the regulated power Pm3 supplied from the hydraulic generator 11 of the hydroelectric power plant 2c to the power grid 5 increases.

[0099] At time t13, when the opening degree of the guide vane 31 of the hydraulic generator 11 of the hydroelectric power plant 2c reaches the opening degree C (see FIG. 3), the regulated power Pm3 supplied from the hydraulic generator 11 of the hydroelectric power plant 2c to the power grid 5 becomes the regulating power of the power generation system 1, and since the battery control mode shifts from the regulating power output mode to the SOC recovery mode, the discharge power Pc of the alkaline storage battery 3 becomes zero.

[0100] At time t14 (10 minutes later in the figure), when the water level detected by the water level gauge 21c provided in the water storage tank 10 of the hydroelectric power plant 2c reaches the target value 3 (see FIG. 5), the hydraulic control mode for the hydraulic generator 11 of the hydroelectric power plant 2c shifts from the regulating water power mode to the water level recovery mode, and the hydraulic control mode for the hydraulic generator 11 of the hydroelectric power plant 2b shifts from the normal water power mode to the regulating water power mode.

[0101] Therefore, the actuator 32c is controlled so that the opening degree of the guide vane 31 of the hydraulic generator 11 of the hydroelectric power plant 2c changes from the opening degree C to the opening degree D (see FIG. 3), and the regulated power Pm3 supplied from the hydraulic generator 11 of the hydroelectric power plant 2c to the power grid 5 decreases.

[0102] On the other hand, at time t14, the power increase control for the hydraulic generator 11 of the hydroelectric power plant 2b is executed by the power generation control device 4. Accordingly, the actuator 32b is controlled so that the opening degree of the guide vane 31 of the hydraulic generator 11 of the hydroelectric power plant 2b changes from the opening degree B to the opening degree C (see FIG. 3), and the regulated power Pm2 supplied from the hydraulic generator 11 of the hydroelectric power plant 2b to the power grid 5 increases.

[0103] At time t15, when the opening degree of the guide vane 31 of the hydraulic generator 11 in the hydroelectric power plant 2b reaches the opening degree D (see Fig. 3), the regulating power Pm3 supplied from the hydraulic generator 11 in the hydroelectric power plant 2c to the power grid 5 becomes 0. When the opening degree of the guide vane 31 of the hydraulic generator 11 in the hydroelectric power plant 2b reaches the opening degree C (see Fig. 3), the regulating power Pm2 supplied from the hydraulic generator 11 in the hydroelectric power plant 2b to the power grid 5 becomes the regulating force of the power generation system 1.

[0104] At time t16 (20 minutes later in the figure), when the water level detected by the water level gauge 21b provided in the water storage tank 10 of the hydroelectric power plant 2b reaches the target value 3 (see Fig. 5), the hydraulic control mode for the hydraulic generator 11 in the hydroelectric power plant 2b shifts from the regulating hydraulic mode to the water level recovery mode, and the hydraulic control mode for the hydraulic generator 11 in the hydroelectric power plant 2c shifts from the normal hydraulic mode to the regulating hydraulic mode.

[0105] Therefore, the actuator 32b is controlled so that the opening degree of the guide vane 31 of the hydraulic generator 11 in the hydroelectric power plant 2b changes from the opening degree C to the opening degree D (see Fig. 3), and the regulating power Pm2 supplied from the hydraulic generator 11 in the hydroelectric power plant 2b to the power grid 5 decreases.

[0106] On the other hand, at time t16, power increase control for the hydraulic generator 11 in the hydroelectric power plant 2c is executed by the power generation control device 4. Therefore, the actuator 32a is controlled so that the opening degree of the guide vane 31 of the hydraulic generator 11 in the hydroelectric power plant 2a changes from the opening degree B to the opening degree C (see Fig. 3), and the regulating power Pm1 supplied from the hydraulic generator 11 in the hydroelectric power plant 2c to the power grid 5 increases.

[0107] At time t17, when the opening degree of the guide vane 31 of the hydraulic generator 11 in the hydroelectric power plant 2b reaches the opening degree D (see Fig. 3), the regulating power Pm2 supplied from the hydraulic generator 11 in the hydroelectric power plant 2b to the power grid 5 becomes 0. When the opening degree of the guide vane 31 of the hydraulic generator 11 in the hydroelectric power plant 2a reaches the opening degree C (see Fig. 3), the regulating power Pm1 supplied from the hydraulic generator 11 in the hydroelectric power plant 2a to the power grid 5 becomes the regulating force of the power generation system 1.

[0108] When the water level detected by the water level gauge 21a provided in the water storage tank 10 of the hydroelectric power plant 2a reaches the target value 3 (see Fig. 5) at time t18 (30 minutes later in the figure), the hydraulic control mode for the hydraulic generator 11 of the hydroelectric power plant 2a shifts from the adjusted hydraulic mode to the water level recovery mode.

[0109] For this reason, the actuator 32c is controlled so that the opening degree of the guide vane 31 of the hydraulic generator 11 of the hydroelectric power plant 2a changes from the opening degree C to the opening degree D (see Fig. 3), and the regulated power Pm3 supplied from the hydraulic generator 11 of the hydroelectric power plant 2c to the power grid 5 decreases.

[0110] In this way, during the period from time t11 to time t12, the regulating power of the power generation system 1 is supplied to the power grid 5 by the discharge power Pc of the alkaline storage battery 3. Also, during the period from time t12 to time t13, the regulating power of the power generation system 1 is supplied to the power grid 5 by the sum of the discharge power Pc of the alkaline storage battery 3 and the regulating power Pm3 of the hydraulic generator 11 of the hydroelectric power plant 2c. Further, during the period from time t13 to time t14, the regulating power of the power generation system 1 is supplied to the power grid 5 by the regulating power Pm3 of the hydraulic generator 11 of the hydroelectric power plant 2c.

[0111] Also, during the period from time t14 to time t15, the regulating power of the power generation system 1 is supplied to the power grid 5 by the sum of the regulating powers Pm3 and Pm2 of the hydraulic generators 11 of the hydroelectric power plants 2c and 2b. Moreover, during the period from time t15 to time t16, the regulating power of the power generation system 1 is supplied to the power grid 5 by the regulating power Pm2 of the hydraulic generator 11 of the hydroelectric power plant 2b.

[0112] Also, during the period from time t16 to time t17, the regulating power of the power generation system 1 is supplied to the power grid 5 by the sum of the regulating powers Pm2 and Pm1 of the hydraulic generators 11 of the hydroelectric power plants 2b and 2a. Further, during the period from time t17 to time t18, the regulating power of the power generation system 1 is supplied to the power grid 5 by the regulating power Pm1 of the hydraulic generator 11 of the hydroelectric power plant 2a.

[0113] <Advantages and effects> As described above, since the power generation system 1 according to the present embodiment can supply a primary regulation power with a response time within 10 seconds and a duration of 5 minutes or more to the power grid 5, the hydraulic generator 11 of the hydroelectric power plant 2a can function as the primary regulation power.

[0114] Further, the power generation system 1 according to the present embodiment can extend the duration by sequentially shifting the hydraulic control modes of the hydraulic generators 11 of the hydroelectric power plants 2a to 2c to the regulated hydraulic mode.

[0115] Therefore, since the power generation system 1 according to the present embodiment can supply a secondary regulation power with a response time within 5 minutes and a duration of 30 minutes or more to the power grid 5, the hydraulic generators 11 of the hydroelectric power plants 2a to 2c can function as the secondary regulation power.

[0116] Also, in the power generation system 1 according to the present embodiment, during the period when the hydraulic control mode for the hydraulic generator 11 of the hydroelectric power plant 2b is the regulated hydraulic mode, the water stored in the water storage tank 10 of the hydroelectric power plant 2b is discharged to the downstream side of the flow path 6, so that the water level of the water storage tank 10 of the hydroelectric power plant 2c can be restored early.

[0117] Furthermore, in the power generation system 1 according to the present embodiment, during the period when the hydraulic control mode for the hydraulic generator 11 of the hydroelectric power plant 2a is the regulated hydraulic mode, the water stored in the water storage tank 10 of the hydroelectric power plant 2a is discharged to the downstream side of the flow path 6, so that the water level of the water storage tank 10 of the hydroelectric power plant 2b can be restored early.

[0118] <Modification Example> Note that, similar to the first embodiment of the present invention, the power generation control device 4 may change the transition condition for shifting the hydraulic control mode for the hydraulic generator 11 of the hydroelectric power plant 2c from the normal hydraulic mode to the regulated hydraulic mode as long as the battery control mode is the regulation power output mode.

[0119] For example, when a certain period (e.g., 1 minute) has elapsed since the power generation control device 4 enters the adjustment power output mode, the water power control mode for the water turbine generator 11 of the hydroelectric power plant 2c may be shifted from the normal water power mode to the adjusted water power mode.

[0120] In the present embodiment, an example in which the power generation control device 4 sequentially shifts the water power control mode for the water turbine generator 11 of the hydroelectric power plant 2c, the water power control mode for the water turbine generator 11 of the hydroelectric power plant 2b, and the water power control mode for the water turbine generator 11 of the hydroelectric power plant 2a to the adjusted water power mode has been described.

[0121] As described above, in the power generation system 1 according to the present embodiment, during the period when the water power control mode for the water turbine generator 11 of the hydroelectric power plant 2b is the adjusted water power mode, the water stored in the water storage tank 10 of the hydroelectric power plant 2b is discharged to the downstream side of the flow path 6, so that the water level of the water storage tank 10 of the hydroelectric power plant 2c can be restored early.

[0122] Further, in the power generation system 1 according to the present embodiment, during the period when the water power control mode for the water turbine generator 11 of the hydroelectric power plant 2a is the adjusted water power mode, the water stored in the water storage tank 10 of the hydroelectric power plant 2a is discharged to the downstream side of the flow path 6, so that the water level of the water storage tank 10 of the hydroelectric power plant 2b can be restored early.

[0123] Therefore, when the water power control mode for the water turbine generator 11 of the hydroelectric power plant 2b shifts from the adjusted water power mode to the water level recovery mode, the water power control mode for the water turbine generator 11 of the hydroelectric power plant 2c can be shifted to the adjusted water power mode.

[0124] Similarly, when the water power control mode for the water turbine generator 11 of the hydroelectric power plant 2a shifts from the adjusted water power mode to the water level recovery mode, the water power control mode for the water turbine generator 11 of the hydroelectric power plant 2b can be shifted to the adjusted water power mode.

[0125] Therefore, as shown in FIG. 9, after sequentially shifting the hydraulic control modes for the hydraulic generators 11 of the hydroelectric power plants 2c, 2b, and 2a to the adjusted hydraulic mode, the power generation control device 4 may further sequentially shift the hydraulic control modes for the hydraulic generators 11 of the hydroelectric power plants 2c and 2b to the adjusted hydraulic mode as shown in FIG. 11.

[0126] In FIG. 11, when the water level detected by the water level gauge 21a provided in the water storage tank 10 of the hydroelectric power plant 2a reaches the target value 3 (see FIG. 5) at time t18 (30 minutes later in the figure), the power generation control device 4 shifts the hydraulic control mode for the hydraulic generator 11 of the hydroelectric power plant 2a to the water level recovery mode and shifts the hydraulic control mode for the hydraulic generator 11 of the hydroelectric power plant 2c to the adjusted hydraulic mode.

[0127] As a result, at time t19, the regulated power Pm1 supplied from the hydraulic generator 11 of the hydroelectric power plant 2a to the power grid 5 becomes 0, and the regulated power Pm3 supplied from the hydraulic generator 11 of the hydroelectric power plant 2c to the power grid 5 becomes the regulating power of the power generation system 1.

[0128] At time t20 (40 minutes later in the figure), when the water level detected by the water level gauge 21c provided in the water storage tank 10 of the hydroelectric power plant 2c reaches the target value 3 (see FIG. 5), the power generation control device 4 shifts the hydraulic control mode for the hydraulic generator 11 of the hydroelectric power plant 2c to the water level recovery mode and shifts the hydraulic control mode for the hydraulic generator 11 of the hydroelectric power plant 2b to the adjusted hydraulic mode.

[0129] As a result, at time t21, the regulated power Pm3 supplied from the hydraulic generator 11 of the hydroelectric power plant 2c to the power grid 5 becomes 0, and the regulated power Pm2 supplied from the hydraulic generator 11 of the hydroelectric power plant 2b to the power grid 5 becomes the regulating power of the power generation system 1.

[0130] When the water level detected by the water level gauge 21b provided in the water storage tank 10 of the hydroelectric power plant 2b reaches the target value 3 (see Fig. 5) at time t22 (50 minutes later in the figure), the power generation control device 4 shifts the hydraulic control mode for the hydraulic generator 11 of the hydroelectric power plant 2b to the water level recovery mode and shifts the hydraulic control mode for the hydraulic generator 11 of the hydroelectric power plant 2c to the adjusted hydraulic mode.

[0131] As a result, at time t23, the adjusted power Pm2 supplied from the hydraulic generator 11 of the hydroelectric power plant 2b to the power grid 5 becomes 0, and the adjusted power Pm3 supplied from the hydraulic generator 11 of the hydroelectric power plant 2c to the power grid 5 becomes the adjustment power of the power generation system 1.

[0132] When the water level detected by the water level gauge 21c provided in the water storage tank 10 of the hydroelectric power plant 2c reaches the target value 3 (see Fig. 5) at time t24 (60 minutes later in the figure), the power generation control device 4 shifts the hydraulic control mode for the hydraulic generator 11 of the hydroelectric power plant 2c to the water level recovery mode.

[0133] By configuring as described above, the power generation system 1 according to the present embodiment can further extend the duration.

[0134] Although the embodiments of the present invention have been disclosed above, it is obvious that the embodiments of the present invention can be modified without departing from the scope of the present invention. The embodiments of the present invention are disclosed on the premise that equivalents to which such modifications are made are included in the invention described in the claims.

Explanation of Reference Numerals

[0135] 1 Power generation system 2, 2a, 2b, 2c Hydroelectric power plants 3 Alkaline storage battery (power storage device) 4 Power generation control device 5 Power grid 6 Flow path 10 Water storage tank 11 Hydraulic generator

Claims

1. A hydroelectric power plant having a hydroelectric generator and capable of supplying power from the hydroelectric generator to a power grid, A power storage device that can be charged from the power grid and can discharge the stored power to the power grid, A power generation control device that controls the hydroelectric generator and the power storage device, and When the power of the power grid is insufficient, the power generation control device executes discharge control to control the power storage device to discharge power to the power grid, and during the period when power is being discharged from the power storage device to the power grid, starts power increase control to control the hydroelectric generator to increase the generated power. A power generation system characterized by this.

2. In the state where the power generation control device is executing the discharge control due to insufficient power of the power grid, when the charge rate of the power storage device becomes equal to or lower than a threshold value, the power increase control is started. The power generation system according to claim 1, characterized by this.

3. In the state where the power generation control device is executing the discharge control due to insufficient power of the power grid, when a predetermined time has elapsed since the start of the discharge control, the power increase control is started. The power generation system according to claim 1, characterized by this.

4. A plurality of hydroelectric power plants having hydroelectric generators and capable of supplying power from the hydroelectric generators to a power grid, A power storage device that can be charged from the power grid and can discharge the stored power to the power grid, A power generation control device that controls the hydroelectric generator and the power storage device, and When the power of the power grid is insufficient, the power generation control device executes discharge control to control the power storage device to discharge power to the power grid, and during the period when power is being discharged from the power storage device to the power grid, starts power increase control to control the hydroelectric generator of at least one of the plurality of hydroelectric power plants to increase the generated power. A power generation system characterized by this.

5. When the power generation control device executes the power increase control due to insufficient power of the power grid, the power increase control is started simultaneously for the hydroelectric generators of the plurality of hydroelectric power plants. The power generation system according to claim 3, characterized by this.

6. The hydroelectric power plant has a water storage tank for storing water supplied to the hydroelectric generator, The power generation control device executes the power increase control by increasing the flow rate of water supplied from the water storage tank to the hydraulic generator. The power generation system according to claim 3, characterized in that.

7. The plurality of small hydropower plants are provided in series so as to form one water flow path. Water is supplied to the water storage tank from the upstream side of the flow path. The water supplied from the water storage tank to the hydraulic generator is discharged from the hydraulic generator to the downstream side of the flow path. In a state where the power generation control device is executing the discharge control due to a shortage of power in the power grid. For the hydraulic generator of the lowermost small hydropower plant, which is the most downstream of the flow path among the plurality of small hydropower plants, when the charge rate of the power storage device becomes equal to or lower than a threshold value, the power increase control is started. For the hydraulic generators of the small hydropower plants other than the lowermost small hydropower plant among the plurality of small hydropower plants, when the water level of the water storage tank of the small hydropower plant on the downstream side of the flow path becomes equal to or lower than a predetermined value, the power increase control is started. The power generation system according to claim 5, characterized in that.

8. A small hydropower plant having a hydraulic generator and capable of supplying power from the hydraulic generator to a power grid. A power generation control device that controls a power storage device that can be charged from the power grid and can discharge the charged power to the power grid. When the power in the power grid is insufficient, it executes a discharge control that controls the power storage device to discharge power to the power grid, and during the period when power is being discharged from the power storage device to the power grid, it starts a power increase control that controls the hydraulic generator to increase the generated power. A power generation control device.

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